Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)

2014-05-07T07:02:32Z

Egbert Casper: /* gml:Solid */

__TOC__

== Document History ==

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0.1.0
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01.10.2010
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Coors
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nicht öffentlich
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Erstfassung
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0.2.0
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14.10.2010
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Coors
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nicht öffentlich
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Solid ergänzt
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0.3.0
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23.10.2010
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Gröger
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nicht öffentlich
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Verschmelzung mit Paper Gröger
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0.4.0
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23.11.2010
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Coors
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nicht öffentlich
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Redaktionelle Änderungen und Ergänzungen zu Planarität von Polygonen
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0.5.0
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24.11.2010
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Gröger
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nicht öffentlich
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Einarbeitung der Änderungen, die im CityGML-Forum von K.-H. Häfele vorgeschlagen wurden
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0.6.0
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15.12.2010
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Gröger
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öffentlich
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Einarbeitung der Anregungen von G. Juen
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0.7.0
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20.01.2012
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Karl-Heinz Häfele
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Konvertierung in Html, Verschiebung des Kapitel Planarität von Polygonen, Neues Kapitel CompositeSolid
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0.7.0 EN
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November 2013
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Egbert Casper, Karl-Heinz Häfele
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public
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English Version </td>
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== References ==
* Cox, S., Daisey, P., Lake, R., Portele, C., Whiteside, A. (2004): OpenGIS Geography Markup Language (GML) Implementation Specification. Version: 3.1.1, OGC 03-105r1,
* Herring J. (2001): The OpenGIS Abstract Specification, Topic 1: Feature Geometry (ISO 19107 Spatial Schema), Open Geospatial Consortium, OGC Document Number 01-101. OGC.
* Gröger, G., Kolbe, T., Czerwinski, A., and Nagel, C. (2008) (Eds.): OpenGIS City Geography Markup Language (CityGML) Encoding Standard, OGC reference number OGC 08-007r1 version 1.0.0, 2008
* Gröger, G., Plümer, L. (2011): How to Achieve Consistency for 3D City Models. Geoinformatica, 15(1):137-165, DOI: 10.1007/s10707-009-0091-6.

== Preliminaries ==
* The rules refer to GML Version 3.1.
* The rules are based on the validity of the data with regard to the XML-Schema of GML 3.1.
* The rules are restricted to the elements of GML that are used in CityGML (Profile of GML, c.f. Figure 1 and Figure 2).
* If a condition applies to CityGML only (not to GML in general), it is stated explicitly.

<table border="0" cellspacing="0">
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[[image:GML-Profil-CityGML-1.png|Profil von GML]]
</td>
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'''Figure 1:''' Profile of GML that is used in CityGML (Primitives and Composites)
</td>
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</table>

<table border="0" cellspacing="0">
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<td>
[[image:GML-Profil-CityGML-2.png|Profilvon]]
</td>
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<td>
'''Figure 2:''' Profile of GML that is used in CityGML (Complexes and Aggregates)
</td>
</tr>
</table>

== <span id="Spatial-Reference-Systems">Spatial Reference Systems (SRS)</span> ==
* Each geometry element (including pos, posList and coordinates) must
** either have a srsName attribute with proper value, or
** inherit the value of the srsName attribute from
*** its parent geometries (even it its obtained recursively from the parents of the parents, etc.), or
*** the gml:Envelope (or gml:Box) which is the value of the gml:boundedBy property of the parent feature or the parent feature collection (even if it is obtained recursively).
* A local value of a srsName attribute precedes the inherited value of a srsName attribute.
* If in geometries (pos, posList) the dimension of a SRS can not be derived from the SRS without a doubt, the attribute srsDimension must contain the dimension of the SRS.

== Definitions ==

=== Geometric Tolerances ===

=== <span id="PlanarityOfPolygons">Planarity of Polygons</span> ===
„Surfaces in CityGML are represented by polygons, which define a planar geometry, i.e. the boundary and all interior points are required to be located in one single plane.” (Gröger et al., 2008). The boundary of a Polygon is defined by one or more planar Linear Rings (see gml:Polygon). From practical point of view, Linear Rings that are not exactly planar should be accepted as a valid as well.
Intuitively, a Linear Ring R would be defined as planar if there is a plane E with distance less than a given threshold  for all points Pi of R. However, this is true for Linear Rings with small bends and folds as shown in Figure 3 as well.

<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="50%">
[[image:Teil1-ABB6a.png|450px]]
</td>
<td width="50%">
[[image:Teil1-ABB6b.png|450px]]
</td>
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<tr align="left" valign="top">
<td colspan="2">
'''Figure 3:''' : Bends and folds should not appear in planar Linear Rings
</td>
</tr>
</table>

In order to avoid such situations, a slightly different definition of planarity of Linear Rings is introduced:

'''Definition 1:'''
A Linear Ring <math>R</math> is '''planar''', if it is a valid Linear Ring and the distance of all points to any plane <math>E_{ijk}</math>, that is defined by three co-linear points <math>P_i</math>, <math>P_j</math> and <math>P_k</math>, is less than a given threshold <math>\epsilon</math> :

<math>\forall E_{ijk} \forall P_a = dist (P_a,E_{ijk})\le \epsilon</math>



== <span id="posList">[http://www.schemacentral.com/sc/niem21/e-gml32_posList.html gml:posList]</span> ==
* The number of items in the list should correlate with the product of the SRS dimension (usually in CityGML 3) and the number of positions.

== <span id="Curve"><span id="LineString">[http://www.schemacentral.com/sc/niem21/e-gml32_Curve.html gml:_Curve], [http://www.schemacentral.com/sc/niem21/e-gml32_LineString.html gml:LineString]</span></span> ==
* Only gml:LineStrings are allowed as subtypes of _Curves (rule applies to CityGML only)
* A gml:LineString has linear interpolation.
* For the child elements of a gml:LineString (control points) the following statements must hold true:
** They form a sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that belong to this curve only. "pointProperty" elements contain points that may be referenced from other geometries or that reference other points (via XLinks) which are defined in other geometries.
** Alternatively, a gml:LineString can be composed of a "posList" element, providing a compact way of representing coordinates. In that case all control points must belong to the same Curve and must be given in the same SRS. The number of points (Direct Position) must be at least two.
* Each control point in a gml:LineString occurs only once, beside the first and the last one which may both be identical.
* Line segments of a gml:LineString are defined by pairs of two subsequent control points. Those line segments must not intersect mutually and must not have any identical points. Exceptions of that rule are the pairs which consist of an endpoint of one line segment and the start point of the next line segment in the sequence.

== <span id="LinearRing">[http://www.schemacentral.com/sc/niem21/e-gml32_LinearRing.html gml:LinearRing]</span> ==

The Linear Ring is the fundamental element to describe 3D geometry in CityGML. Every single polygon of a building geometry is defined by its boundary – the Linear Ring.

A sequence is an ordered list of elements. Unlike a set, order matters, and the exact same elements can appear multiple times at different positions in the sequence. A finite sequence <math>a</math> with <math>n+1</math> elements is denoted as <math>a=(a_0,a_1,...,a_n)</math>. The empty sequence <math>a=()</math> has no elements..

A finite sequence of points <math>R=(P_0,P_1,...,P_n),n\ge3,P_i=(x_i,y_i,z_i)</math> is a Linear Ring if:

(i) the first and last point <math>P_0</math> and <math>P_n</math> represent the same point: <math>P_0 =P_n </math> '''(closeness)'''

(ii) All points of the sequence besides start and end point are different:
<math>\underset{\underset {i \ne k}{\underset{k=0...n-1}{i=0...n-1}}}{\forall} P_i\ne P_k</math>

(iii) Two edges <math>(P_i , P_{i+1})</math> and <math>(P_k , P_{k+1})</math> <math>i = 0 ... (n-1), k= 0 ... (n-1), i \not= k</math> do only intersect in one start-/ endpoint. No other intersection is allowed (no self intersection).

If all points of the sequence are co-planar, the Linear Ring is planar.

'''Examples:'''

<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="33%">
<math>R=(P_0,P_1,P_2,P_3,P_0)</math>

with

<math>P_0 =(1,1,1)</math>

<math>P_1 =(3,1,1)</math>

<math>P_2 =(3,3,1)</math>

<math>P_3 =(1,3,1)</math>
</td>
<td width="33%">
<gml:LinearRing>

<gml:pos> 1 1 1 </gml:pos>

<gml:pos> 3 1 1 </gml:pos>

<gml:pos> 3 3 1 </gml:pos>

<gml:pos> 1 3 1 </gml:pos>

<gml:pos> 1 1 1 </gml:pos>

</gml:LinearRing>
</td>
<td>
[[image:Teil1-ABB3.png]]
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<td colspan="3">
'''Figure 4:''' Planar Linear Ring: definition, GML and graphic representation
</td>
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</table>

'''Please note:'''
The two Linear Rings <math>R_1 = (P_0,P_1,P_2,P_3,P_0)</math> and <math>R_2 = (P_0,P_3,P_2,P_1,P_0)</math> are not identical.

<table width="900px" border="0" cellspacing="0" cellpadding="5">
<tr align="left" valign="top">
<td width="33%">
[[image:Teil1-ABB4a.png]]</td>
<td width="33%">
[[image:Teil1-ABB4b.png]]</td>
<td>
[[image:Teil1-ABB4c.png]]
</td>
</tr>
<tr align="left" valign="top">
<td width="33%">
<math>R=(P_0,P_1,P_2,P_3)</math>
</td>
<td width="33%">
<math>R=(P_0,P_1,P_3,P_2,P_0)</math>
</td>
<td>
<math>R=(P_0,P_1,P_4,P_3,P_2,P_4,P_0)</math>
</td>
</tr>
<tr align="left" valign="top">
<td width="33%">
No Linear Ring: not closed (see (i) closeness)

</td>
<td width="33%">
No Linear Ring:self intersection (see (iii) self-intersection)

</td>
<td>
No Linear Ring: <math>P_4</math> appears twice in the sequence (see (ii), <math>P_4=(2,2,1)</math>)
</td>
</tr>

<tr align="left" valign="top">
<td colspan="3">
'''Figure 5:''' Examples of non-valid Linear Rings</td>
</tr>
</table>

<table width="600px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="33%">
[[image:Teil1-ABB5a.png|250px]]</td>
<td width="33%">
[[image:Teil1-ABB5b.png]]</td>

</tr>
<tr align="left" valign="top">
<td width="33%">
<math>R=(P_0,P_1,P_2,P_4,P_3,P_0)</math>
</td>
<td width="33%">
<math>R=(P_0,P_1,P_2,P_0)</math>
</td>

</tr>
<tr align="left" valign="top">
<td width="33%">
Linear Ring, but not planar <math>P_4=(2,4,0)</math></td>
<td width="33%">
No Linear Ring: all 3 points are co-linear; self-intersection (see (iii))
</td>

</tr>

<tr align="left" valign="top">
<td colspan="3">
'''Figure 6:''' Special cases: non-planar and co-linear Linear Ring Elements.</td>
</tr>
</table>

== <span id="Polygon">[http://www.schemacentral.com/sc/niem21/e-gml32_Polygon.html gml:Polygon]</span> ==
* A Polygon <math>S</math> is defined by a planar Linear Ring <math>R_s</math> (exterior ring).
* A polygon has exactly one exterior ring. In addition, a polygon can have <math>n\ge0</math> interior rings. These interior rings a planar Linear Rings as well. All interior rings and the exterior ring must be on the same plane (within the given tolerance).
* As interior rings define holes in the polygon, they have to be completely included in the area defined by the exterior ring.
<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:InnerLoops-02-2.png|500px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 7:''' Polygon mit <span style="color:#008000">korrektem interior Ring (links)</span> und <span style="color:#FF0000">nicht korrektem inneren Ring (rechts)</span> </td>
</tr>
</table>
* Interior rings must not overlap other Linear Rings or be included in another Linear Ring (except the exterior Linear Ring).
<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:InnerLoops-04-2.png|500px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 8:''' Polygon with <span style="color:#008000">two correct interior Rings (left)</span> and two interlaced, <span style="color:#FF0000">not correct interior Rings (right)</span> </td>
</tr>
</table>
* Interior rings and the exterior ring may touch each other in a finite number of points. The inner area of the polygon has to be connected.
<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:InnerLoops-05-2.png|500px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 9:''' Polygon with <span style="color:#008000">correct, interior Ring, der den außeren Ring an einem Punkt berührt (left)</span> and <span style="color:#FF0000">not correct interior Ring, der den äußeren Ring an zwei Punkten berührt und damit dass Polygon spaltet (rechts)</span> </td>
</tr>
</table>
* • The order of points of the exterior ring defines the orientation of the polygon. The non co-linear points <math>P_i</math>, <math>P_j</math> und <math>P_k</math>define the plane <math>E(P_i,P_j,P_k)</math>. The normal vector <math>\vec n</math> is given by the cross product of the two vectors <math>\vec{P_iP_j}</math> and <math>\vec{P_jP_k}</math>:

<math>\vec n = \frac {\vec{P_iP_j}\times\vec{P_jP_k}}{\| {\vec{P_iP_j}\times\vec{P_jP_k}}\|}</math>

'''Please note:''' that due to the tolerance of planar Linear Rings, the normal vector can be ambiguous.

'''Remark:'''
The two Linear Rings <math>R_1=(P_0,P_1,P_2,P_3,P_0)</math> and <math>R_2=(P_0,P_3,P_2,P_1,P_0)</math> define polygons with the same geometric extend but different orientation.

<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:Teil1-ABB7.png|300px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 10:''' Polygon with normal vector n</td>
</tr>
</table>

== <span id="OrientableSurface">[http://www.schemacentral.com/sc/niem21/e-gml32_OrientableSurface.html gml:OrientableSurface]</span> ==
* If the value of the attribute “orientation” of an OrientableSurface is "+", the orientation of the OrientableSurface is identical to the one of the baseSurface. If the value of “orientation is " ", the normal of the OrientableSurface has a direction which is opposite to the normal of the baseSurface. The default value of “orientation” is "+".
* Either the element “baseSurface” references the base surface via a XLink attribute or the element “baseSurface” contains the base surface as child element. The base surface has positive orientation.

== <span id="MultiSurface">[http://www.schemacentral.com/sc/niem21/e-gml32_MultiSurface.html gml:MultiSurface]</span> ==
A MultiSurface is an unstructured set <math>M=\lbrace S_1,S_2,...S_n\rbrace</math> of polygons. No further constraints are defined for a MultiSurface element. It is not necessary that <math>M</math> is a connected surface. Orientation of the polygons is arbitrary. By a MultiSurface any existing polygonal boundary representation of a rigid body can be described. Unfortunately, also objects that do not exist in real space can be modeled.

Due to the missing constraints it is recommended that MultiSurface elements should only be used to model non-volumetric parts of the building model as shown in Figure 11. Volumetric parts should be modeled as solids (see gml:Solid)

<table width="700px" border="0" cellspacing="0">

<tr align="left" valign="top">
<td width="50%">
[[image:MultiSurface-01a.png|300px]]
</td>
<td width="50%">
[[image:MultiSurface-01a.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td width="50%">
[[image:MultiSurface-Explode-01a.png|300px]]
</td>
<td width="50%">
[[image:MultiSurface-Explode-01b.png|300px]]
</td>
</tr>

<tr align="left" valign="top">
<td colspan="2">
'''Figure 11:''' Modeling overlapping roof parts ('''above:''' complete models, polygons outlined; '''below:''' roof polygons exploded)

'''Please note:''' the left model in Figure 11 is created with a MultiSurface element containing 7 polygons. However, the polygons do not represent a valid boundary of a rigid body. Calculating a volume is not possible. The right model is the same building geometry but modeled with 1 Solid element (7 polygons) and 1 MultiSurface element (2 polygons F6 and F8) as recommended (see CityGML Standard v1.0,p.61)

</td>
</tr>
</table>

== <span id="CompositeSurface"> [http://www.schemacentral.com/sc/niem21/e-gml32_CompositeSurface.html gml:CompositeSurface]</span>==

Eine CompositeSurface ist eine Menge <math>C=\lbrace S_1,S_2,...,S_n \rbrace</math> von Polygonen, für die
folgendes gilt:

# Die Schnittmenge zweier Polygone <math>S_k</math> und <math>S_l</math> aus <math>C</math> ist entweder leer oder besteht nur aus Punkten und/oder Kanten, die auch in den beiden linearen Ringen vorkommen. Bezeichne <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math> den planaren linearen Ring, der das Polygon <math>S</math> definiert. Dann gilt:<br><math>S_i \cap S_k= \begin{cases}\emptyset\\ \lbrace Q_0,Q_1,...,Q_m\rbrace,Q_j=P_k^i\\ \lbrace e_0,e_1,...,e_m\rbrace,e_j=\overline{P_i^kP_{i+1}^k} \end{cases}</math>
# Jede Kante <math>e_k=\overline{P_i^kP_{i+1}^k}</math> eines linearen Rings <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math> , der ein Polygon <math>S_k \in C</math> definiert, wird höchstens einmal als Kante <math>e_l=\overline{P_j^lP_{j+1}^l}</math> in einem linearen Ring <math>R_l=(P_0^l,P_1^l,...,P_m^l)</math> genutzt, der ein anderes Polygon <math>S_l \in C</math> definiert.<br>Es gilt <math>P_i^k=P_{j+1}^l</math> und <math>P_{i+1}=P_j^l</math>.
# Die Polygone aus <math>C</math> sind so orientiert, dass die Flächennormale benachbarte Polygone in dieselbe Richtung zeigen.
# Die Vereinigung aller Polygone aus <math>C</math> ohne die Kanten oder Punkte, in denen sich die Polygone berühren, ist isomorph zu einem Polygon.

Aus (1) und (2) ergibt sich, dass die Oberfläche, die durch <math>C</math> beschrieben wird, keine sich gegenseitig überlappenden oder durchdringenden Polygone enthalten darf (Polygone berühren sich höchstens in Punkten oder Kanten).

== <span id="Solid"> [http://www.schemacentral.com/sc/niem21/e-gml32_Solid.html gml:Solid]</span>==

A solid geometry represents a rigid body. The surface of the solid is defined by a set of polygons with the following properties.
The set <math>C=\lbrace S_1,S_2,...,S_n \rbrace</math> of polygons bounds a solid if:

# The intersection of two polygons <math>S_k</math> and <math>S_l</math> of <math>C</math> is either empty or contains only points <math>P</math> and edges <math>e</math> that are part of both Linear Rings. The polygon <math>S</math> is defined by the Linear Ring <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math>. The intersection of <math>S_k</math> and <math>S_l</math> equals: <br><math>S_i \cap S_k= \begin{cases}\emptyset\\ \lbrace Q_0,Q_1,...,Q_m\rbrace,Q_j=P_k^i\\ \lbrace e_0,e_1,...,e_m\rbrace,e_j=\overline{P_i^kP_{i+1}^k} \end{cases}</math>
# Every Edge <math>e_k=\overline{P_i^kP_{i+1}^k}</math> of a Linear Ring <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math> , defining a polygon <math>S_k \in C</math>, is used exactly once as an edge <math>e_l=\overline{P_j^lP_{j+1}^l}</math> in a Linear Ring <math>R_l=(P_0^l,P_1^l,...,P_m^l)</math>, defining another polygon <math>S_l \in C</math> with <math>P_i^k=P_{j+1}^l</math> and <math>P_{i+1}=P_j^l</math>.
# All polygons in <math>C</math> are oriented such that the normal vector of each polygon points to the outside of the solid.
# All polygons in <math>C</math> are connected, that is the dual graph of <math>C</math> has a path containing all nodes. The dual graph G<sub>C</sub> =(V<sub>C</sub>, E<sub>C</sub>) of <math>C</math> consists of a set V<sub>C</sub> of nodes and a set E<sub>C</sub> of edges. Every node v of V<sub>C</sub> represents exactly one polygon of <math>C</math>. An edge shared by two polygons <math>S_k</math> and <math>S_l</math> of <math>C</math> is represented by an edge <math>e=(v_{s_k},v_{s_l})</math> in E<sub>C</sub>.
# For every point <math>P</math> of a Linear Ring of a polygon of <math>C </math> applies: The graph <math>G_P =(V_P, E_P)</math>, that is only build by polygons and edges that touch<math>P</math> is connected. Each node <math>v</math> of <math>V_P</math> represents a polygon which Linear Ring contains <math>P</math>. Two nodes are connected by an edge <math>e</math> of <math>E_P</math> if the two polygons represented by the nodes have a common edge that touches <math>P</math>.

It follows from (i) and (ii) that the surface defined by <math>C</math> has no holes. Together with conditions (4) and (5) it follows that the inner of the solid defined by <math>C</math> is connected
<math>S</math> is denoted as closed [http://www.schemacentral.com/sc/niem21/e-gml32_CompositeSurface.html '''CompositeSurface'''].

'''Examples:'''

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:Solid-Fall-01.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-02.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-03.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-04.png|200px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="top">
correct: 6 surfaces, closed, correct surface orientation
</td>
<td width="300px" valign="top">
correct: 11 surfaces, closed, correct surface orientation
</td>
<td width="300px" valign="top">
correct: 10 surfaces, closed, correct surface orientation
</td>
<td width="300px" valign="top">
correct: 30 surfaces, closed, correct surface orientation
</td>
</tr>
</table>

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:Solid-Fall-05.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-06.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-07.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-08.png|200px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="top">
incorrect: 5 surfaces, not closed, correct surface orientation
</td>
<td width="300px" valign="top">
incorrect: 6 surfaces, closed, incorrect surface orientation
</td>
<td width="300px" valign="top">
incorrect: 12 surfaces, no closed (zwei Außenhüllen), correct surface orientation
</td>
<td width="300px" valign="top">
incorrect: 12 surfaces, not closed (innere und äußere Hülle), correct surface orientation
</td>
</tr>
</table>

== <span id="CompositeSolid">[http://www.schemacentral.com/sc/niem21/e-gml32_CompositeSolid.html gml:CompositeSolid]</span>==
Ein CompositeSolid wird durch eine nichtleere Menge <math>C = \{S_1,..., S_n\}</math> von '''[[#Solid|Solids]]''' (vgl. 12.) beschrieben, für die gilt:

# Der Schnitt der Inneren zweier Solids <math>S_i</math>, <math>S_j</math>, 1 ≤ i ≤ n, 1 ≤ j ≤ n, i ≠ j, ist leer, d.h. entweder sind beide Solids <math>S_i</math>, <math>S_j</math> disjunkt oder beide berühren sich nur in Flächen, Linien oder Punkten
# Sei <math>C'</math> die Vereinigung aller Solids aus <math>C</math>. Dann ist die Begrenzung von <math>C'</math> (die Oberfläche von <math>C'</math> ohne die Flächen oder Punkte, in denen sich die Solids berühren) die Begrenzung eines Solid.

In CityGML werden bei CompositeSolids ebenso wie bei Solids innere Einschlüsse (Hohlräume) nicht betrachtet.

'''Examples:'''

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:CompositeSolid-01-Fall01.png|300px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall02.png|220px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall03.png|240px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall04.png|260px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="bottom">
correct; surface contact
</td>
<td width="300px" valign="bottom">
correct; surface contact
</td>
<td width="300px" valign="bottom">
correct; surface contact
</td>
<td width="300px" valign="bottom">
correct; surface contact
</td>

</tr>

</table>

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:CompositeSolid-01-Fall05.png|260px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall06.png|260px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall07.png|280px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall08.png|180px]]
</td>

</tr>

<tr align="middle">

<td width="300px" valign="bottom">
not correct; line contact
</td>
<td width="300px" valign="bottom">
not correct; point contact
</td>
<td width="300px" valign="bottom">
not correct; no contact at all
</td>
<td width="300px" valign="bottom">
not correct; intersection
</td>

</tr>

</table>

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:CompositeSolid-01-Fall14.png|220px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall14a.png|220px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall14b.png|220px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="bottom">
not correct; 26 boxes with surface contact
</td>
<td width="300px" valign="bottom">
but with internal hollow space
</td>
<td width="300px" valign="bottom">
not correct; interior boundaries
</td>

</tr>

</table>

== <span id="Triangle">[http://www.schemacentral.com/sc/niem21/e-gml32_Triangle.html gml:Triangle]</span> ==
* A Triangle is a special case of a polygon that is bounded by one outer Linear Ring with four points.
* There are no interior rings (no element "interior").

== <span id="TriangulatedSurface">[http://www.schemacentral.com/sc/niem21/e-gml32_TriangulatedSurface.html gml:TriangulatedSurface]</span> ==
A triangulated surface is a [[#CompositeSurface|CompositeSurface]] that consists of triangles only, but is not closed (it may have boundaries). There is no restriction on how the triangulation is derived.

== <span id="TIN">[http://www.schemacentral.com/sc/niem21/e-gml32_Tin.html gml:Tin] </span>==
In contrast to a gml:TriangulatedSurface, the triangles of a gml:TIN are not represented explicitly, but by its three vertices (called control points). In addition, breaklines, stop lines and the maximal length of a side of a triangle can be represented in a gml:TIN.

# A TIN is a triangulated surface that is the result of the application of a Delaunay Algorithm or of a similar algorithm (extended by breaklines, stop lines and the maximal length of a side of a triangle). The surface satisfies the Delaunay criterion:
## For each triangle in the network, the circle passing through its vertices does not contain, in its interior, the vertex of any other triangle.
# Stoplines are lines where the local continuity or regularity of the surface is questionable. In the area of these pathologies, triangles intersecting a stopline shall be removed from the TIN surface, leaving holes in the surface. If triangles incident to the boundary of the surfaces are removed, the boundary of the surfaces changes.
# Breaklines are lines that are critical for the shape of the surface, representing local ridges, or depressions (such as drainage lines) in the surface. As such their constituent segments must be included in the TIN even if doing so violates the Delaunay criterion.
# Areas of the surface where the data is not sufficiently dense to assure reasonable calculations shall be removed by adding a retention criterion for triangles based on the length of their sides. For any triangle sides exceeding maximum length, the adjacent triangles to that triangle side shall be removed from the surface. # The number of control points is at least three.
# The surface is not affected by the order in which the control points are given. Application schemas may add information based on the ordering of the control points to facilitate the reconstruction of the TIN from the control points.

Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)

2014-05-07T06:47:27Z

Egbert Casper: /* Planarity of Polygons */

__TOC__

== Document History ==

<table border="1" cellspacing="0">
<tr align="left" valign="top">
<th width="220">
Version
</th>
<th width="220">
Date
</th>
<th width="220">
Author/s
</th>
<th width="220">
Status
</th>
<th width="220">
Remarks
</th>
</tr>

<tr align="left" valign="top">
<td>
0.1.0
</td>
<td width="220">
01.10.2010
</td>
<td>
Coors
</td>
<td>
nicht öffentlich
</td>
<td>
Erstfassung
</td>
</tr>
<tr align="left" valign="top">
<td>
0.2.0
</td>
<td width="220">
14.10.2010
</td>
<td>
Coors
</td>
<td>
nicht öffentlich
</td>
<td>
Solid ergänzt
</td>
</tr>

<tr align="left" valign="top">
<td>
0.3.0
</td>
<td width="220">
23.10.2010
</td>
<td>
Gröger
</td>
<td>
nicht öffentlich
</td>
<td>
Verschmelzung mit Paper Gröger
</td>
</tr>

<tr align="left" valign="top">
<td>
0.4.0
</td>
<td width="220">
23.11.2010
</td>
<td>
Coors
</td>
<td>
nicht öffentlich
</td>
<td>
Redaktionelle Änderungen und Ergänzungen zu Planarität von Polygonen
</td>
</tr>

<tr align="left" valign="top">
<td>
0.5.0
</td>
<td width="220">
24.11.2010
</td>
<td>
Gröger
</td>
<td>
nicht öffentlich
</td>
<td>
Einarbeitung der Änderungen, die im CityGML-Forum von K.-H. Häfele vorgeschlagen wurden
</td>
</tr>

<tr align="left" valign="top" bgcolor="green">
<td>
0.6.0
</td>
<td width="220">
15.12.2010
</td>
<td>
Gröger
</td>
<td>
öffentlich
</td>
<td>
Einarbeitung der Anregungen von G. Juen
</td>
</tr>

<tr align="left" valign="top">
<td>
0.7.0
</td>
<td width="220">
20.01.2012
</td>
<td>
Karl-Heinz Häfele
</td>
<td>
nicht öffentlich
</td>
<td>
Konvertierung in Html, Verschiebung des Kapitel Planarität von Polygonen, Neues Kapitel CompositeSolid
</td>
</tr>
<tr align="left" valign="top">
<td>
0.7.0 EN
</td>
<td width="220">
November 2013
</td>
<td>
Egbert Casper, Karl-Heinz Häfele
</td>
<td>
public
</td>
<td>
English Version </td>
</tr>

</table>

== References ==
* Cox, S., Daisey, P., Lake, R., Portele, C., Whiteside, A. (2004): OpenGIS Geography Markup Language (GML) Implementation Specification. Version: 3.1.1, OGC 03-105r1,
* Herring J. (2001): The OpenGIS Abstract Specification, Topic 1: Feature Geometry (ISO 19107 Spatial Schema), Open Geospatial Consortium, OGC Document Number 01-101. OGC.
* Gröger, G., Kolbe, T., Czerwinski, A., and Nagel, C. (2008) (Eds.): OpenGIS City Geography Markup Language (CityGML) Encoding Standard, OGC reference number OGC 08-007r1 version 1.0.0, 2008
* Gröger, G., Plümer, L. (2011): How to Achieve Consistency for 3D City Models. Geoinformatica, 15(1):137-165, DOI: 10.1007/s10707-009-0091-6.

== Preliminaries ==
* The rules refer to GML Version 3.1.
* The rules are based on the validity of the data with regard to the XML-Schema of GML 3.1.
* The rules are restricted to the elements of GML that are used in CityGML (Profile of GML, c.f. Figure 1 and Figure 2).
* If a condition applies to CityGML only (not to GML in general), it is stated explicitly.

<table border="0" cellspacing="0">
<tr align="left" valign="top">
<td>
[[image:GML-Profil-CityGML-1.png|Profil von GML]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Figure 1:''' Profile of GML that is used in CityGML (Primitives and Composites)
</td>
</tr>
</table>

<table border="0" cellspacing="0">
<tr align="left" valign="top">
<td>
[[image:GML-Profil-CityGML-2.png|Profilvon]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Figure 2:''' Profile of GML that is used in CityGML (Complexes and Aggregates)
</td>
</tr>
</table>

== <span id="Spatial-Reference-Systems">Spatial Reference Systems (SRS)</span> ==
* Each geometry element (including pos, posList and coordinates) must
** either have a srsName attribute with proper value, or
** inherit the value of the srsName attribute from
*** its parent geometries (even it its obtained recursively from the parents of the parents, etc.), or
*** the gml:Envelope (or gml:Box) which is the value of the gml:boundedBy property of the parent feature or the parent feature collection (even if it is obtained recursively).
* A local value of a srsName attribute precedes the inherited value of a srsName attribute.
* If in geometries (pos, posList) the dimension of a SRS can not be derived from the SRS without a doubt, the attribute srsDimension must contain the dimension of the SRS.

== Definitions ==

=== Geometric Tolerances ===

=== <span id="PlanarityOfPolygons">Planarity of Polygons</span> ===
„Surfaces in CityGML are represented by polygons, which define a planar geometry, i.e. the boundary and all interior points are required to be located in one single plane.” (Gröger et al., 2008). The boundary of a Polygon is defined by one or more planar Linear Rings (see gml:Polygon). From practical point of view, Linear Rings that are not exactly planar should be accepted as a valid as well.
Intuitively, a Linear Ring R would be defined as planar if there is a plane E with distance less than a given threshold  for all points Pi of R. However, this is true for Linear Rings with small bends and folds as shown in Figure 3 as well.

<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="50%">
[[image:Teil1-ABB6a.png|450px]]
</td>
<td width="50%">
[[image:Teil1-ABB6b.png|450px]]
</td>
</tr>
<tr align="left" valign="top">
<td colspan="2">
'''Figure 3:''' : Bends and folds should not appear in planar Linear Rings
</td>
</tr>
</table>

In order to avoid such situations, a slightly different definition of planarity of Linear Rings is introduced:

'''Definition 1:'''
A Linear Ring <math>R</math> is '''planar''', if it is a valid Linear Ring and the distance of all points to any plane <math>E_{ijk}</math>, that is defined by three co-linear points <math>P_i</math>, <math>P_j</math> and <math>P_k</math>, is less than a given threshold <math>\epsilon</math> :

<math>\forall E_{ijk} \forall P_a = dist (P_a,E_{ijk})\le \epsilon</math>



== <span id="posList">[http://www.schemacentral.com/sc/niem21/e-gml32_posList.html gml:posList]</span> ==
* The number of items in the list should correlate with the product of the SRS dimension (usually in CityGML 3) and the number of positions.

== <span id="Curve"><span id="LineString">[http://www.schemacentral.com/sc/niem21/e-gml32_Curve.html gml:_Curve], [http://www.schemacentral.com/sc/niem21/e-gml32_LineString.html gml:LineString]</span></span> ==
* Only gml:LineStrings are allowed as subtypes of _Curves (rule applies to CityGML only)
* A gml:LineString has linear interpolation.
* For the child elements of a gml:LineString (control points) the following statements must hold true:
** They form a sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that belong to this curve only. "pointProperty" elements contain points that may be referenced from other geometries or that reference other points (via XLinks) which are defined in other geometries.
** Alternatively, a gml:LineString can be composed of a "posList" element, providing a compact way of representing coordinates. In that case all control points must belong to the same Curve and must be given in the same SRS. The number of points (Direct Position) must be at least two.
* Each control point in a gml:LineString occurs only once, beside the first and the last one which may both be identical.
* Line segments of a gml:LineString are defined by pairs of two subsequent control points. Those line segments must not intersect mutually and must not have any identical points. Exceptions of that rule are the pairs which consist of an endpoint of one line segment and the start point of the next line segment in the sequence.

== <span id="LinearRing">[http://www.schemacentral.com/sc/niem21/e-gml32_LinearRing.html gml:LinearRing]</span> ==

The Linear Ring is the fundamental element to describe 3D geometry in CityGML. Every single polygon of a building geometry is defined by its boundary – the Linear Ring.

A sequence is an ordered list of elements. Unlike a set, order matters, and the exact same elements can appear multiple times at different positions in the sequence. A finite sequence <math>a</math> with <math>n+1</math> elements is denoted as <math>a=(a_0,a_1,...,a_n)</math>. The empty sequence <math>a=()</math> has no elements..

A finite sequence of points <math>R=(P_0,P_1,...,P_n),n\ge3,P_i=(x_i,y_i,z_i)</math> is a Linear Ring if:

(i) the first and last point <math>P_0</math> and <math>P_n</math> represent the same point: <math>P_0 =P_n </math> '''(closeness)'''

(ii) All points of the sequence besides start and end point are different:
<math>\underset{\underset {i \ne k}{\underset{k=0...n-1}{i=0...n-1}}}{\forall} P_i\ne P_k</math>

(iii) Two edges <math>(P_i , P_{i+1})</math> and <math>(P_k , P_{k+1})</math> <math>i = 0 ... (n-1), k= 0 ... (n-1), i \not= k</math> do only intersect in one start-/ endpoint. No other intersection is allowed (no self intersection).

If all points of the sequence are co-planar, the Linear Ring is planar.

'''Examples:'''

<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="33%">
<math>R=(P_0,P_1,P_2,P_3,P_0)</math>

with

<math>P_0 =(1,1,1)</math>

<math>P_1 =(3,1,1)</math>

<math>P_2 =(3,3,1)</math>

<math>P_3 =(1,3,1)</math>
</td>
<td width="33%">
<gml:LinearRing>

<gml:pos> 1 1 1 </gml:pos>

<gml:pos> 3 1 1 </gml:pos>

<gml:pos> 3 3 1 </gml:pos>

<gml:pos> 1 3 1 </gml:pos>

<gml:pos> 1 1 1 </gml:pos>

</gml:LinearRing>
</td>
<td>
[[image:Teil1-ABB3.png]]
</td>
</tr>
<tr align="left" valign="top">
<td colspan="3">
'''Figure 4:''' Planar Linear Ring: definition, GML and graphic representation
</td>
</tr>
</table>

'''Please note:'''
The two Linear Rings <math>R_1 = (P_0,P_1,P_2,P_3,P_0)</math> and <math>R_2 = (P_0,P_3,P_2,P_1,P_0)</math> are not identical.

<table width="900px" border="0" cellspacing="0" cellpadding="5">
<tr align="left" valign="top">
<td width="33%">
[[image:Teil1-ABB4a.png]]</td>
<td width="33%">
[[image:Teil1-ABB4b.png]]</td>
<td>
[[image:Teil1-ABB4c.png]]
</td>
</tr>
<tr align="left" valign="top">
<td width="33%">
<math>R=(P_0,P_1,P_2,P_3)</math>
</td>
<td width="33%">
<math>R=(P_0,P_1,P_3,P_2,P_0)</math>
</td>
<td>
<math>R=(P_0,P_1,P_4,P_3,P_2,P_4,P_0)</math>
</td>
</tr>
<tr align="left" valign="top">
<td width="33%">
No Linear Ring: not closed (see (i) closeness)

</td>
<td width="33%">
No Linear Ring:self intersection (see (iii) self-intersection)

</td>
<td>
No Linear Ring: <math>P_4</math> appears twice in the sequence (see (ii), <math>P_4=(2,2,1)</math>)
</td>
</tr>

<tr align="left" valign="top">
<td colspan="3">
'''Figure 5:''' Examples of non-valid Linear Rings</td>
</tr>
</table>

<table width="600px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="33%">
[[image:Teil1-ABB5a.png|250px]]</td>
<td width="33%">
[[image:Teil1-ABB5b.png]]</td>

</tr>
<tr align="left" valign="top">
<td width="33%">
<math>R=(P_0,P_1,P_2,P_4,P_3,P_0)</math>
</td>
<td width="33%">
<math>R=(P_0,P_1,P_2,P_0)</math>
</td>

</tr>
<tr align="left" valign="top">
<td width="33%">
Linear Ring, but not planar <math>P_4=(2,4,0)</math></td>
<td width="33%">
No Linear Ring: all 3 points are co-linear; self-intersection (see (iii))
</td>

</tr>

<tr align="left" valign="top">
<td colspan="3">
'''Figure 6:''' Special cases: non-planar and co-linear Linear Ring Elements.</td>
</tr>
</table>

== <span id="Polygon">[http://www.schemacentral.com/sc/niem21/e-gml32_Polygon.html gml:Polygon]</span> ==
* A Polygon <math>S</math> is defined by a planar Linear Ring <math>R_s</math> (exterior ring).
* A polygon has exactly one exterior ring. In addition, a polygon can have <math>n\ge0</math> interior rings. These interior rings a planar Linear Rings as well. All interior rings and the exterior ring must be on the same plane (within the given tolerance).
* As interior rings define holes in the polygon, they have to be completely included in the area defined by the exterior ring.
<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:InnerLoops-02-2.png|500px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 7:''' Polygon mit <span style="color:#008000">korrektem interior Ring (links)</span> und <span style="color:#FF0000">nicht korrektem inneren Ring (rechts)</span> </td>
</tr>
</table>
* Interior rings must not overlap other Linear Rings or be included in another Linear Ring (except the exterior Linear Ring).
<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:InnerLoops-04-2.png|500px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 8:''' Polygon with <span style="color:#008000">two correct interior Rings (left)</span> and two interlaced, <span style="color:#FF0000">not correct interior Rings (right)</span> </td>
</tr>
</table>
* Interior rings and the exterior ring may touch each other in a finite number of points. The inner area of the polygon has to be connected.
<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:InnerLoops-05-2.png|500px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 9:''' Polygon with <span style="color:#008000">correct, interior Ring, der den außeren Ring an einem Punkt berührt (left)</span> and <span style="color:#FF0000">not correct interior Ring, der den äußeren Ring an zwei Punkten berührt und damit dass Polygon spaltet (rechts)</span> </td>
</tr>
</table>
* • The order of points of the exterior ring defines the orientation of the polygon. The non co-linear points <math>P_i</math>, <math>P_j</math> und <math>P_k</math>define the plane <math>E(P_i,P_j,P_k)</math>. The normal vector <math>\vec n</math> is given by the cross product of the two vectors <math>\vec{P_iP_j}</math> and <math>\vec{P_jP_k}</math>:

<math>\vec n = \frac {\vec{P_iP_j}\times\vec{P_jP_k}}{\| {\vec{P_iP_j}\times\vec{P_jP_k}}\|}</math>

'''Please note:''' that due to the tolerance of planar Linear Rings, the normal vector can be ambiguous.

'''Remark:'''
The two Linear Rings <math>R_1=(P_0,P_1,P_2,P_3,P_0)</math> and <math>R_2=(P_0,P_3,P_2,P_1,P_0)</math> define polygons with the same geometric extend but different orientation.

<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:Teil1-ABB7.png|300px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 10:''' Polygon with normal vector n</td>
</tr>
</table>

== <span id="OrientableSurface">[http://www.schemacentral.com/sc/niem21/e-gml32_OrientableSurface.html gml:OrientableSurface]</span> ==
* If the value of the attribute “orientation” of an OrientableSurface is "+", the orientation of the OrientableSurface is identical to the one of the baseSurface. If the value of “orientation is " ", the normal of the OrientableSurface has a direction which is opposite to the normal of the baseSurface. The default value of “orientation” is "+".
* Either the element “baseSurface” references the base surface via a XLink attribute or the element “baseSurface” contains the base surface as child element. The base surface has positive orientation.

== <span id="MultiSurface">[http://www.schemacentral.com/sc/niem21/e-gml32_MultiSurface.html gml:MultiSurface]</span> ==
A MultiSurface is an unstructured set <math>M=\lbrace S_1,S_2,...S_n\rbrace</math> of polygons. No further constraints are defined for a MultiSurface element. It is not necessary that <math>M</math> is a connected surface. Orientation of the polygons is arbitrary. By a MultiSurface any existing polygonal boundary representation of a rigid body can be described. Unfortunately, also objects that do not exist in real space can be modeled.

Due to the missing constraints it is recommended that MultiSurface elements should only be used to model non-volumetric parts of the building model as shown in Figure 11. Volumetric parts should be modeled as solids (see gml:Solid)

<table width="700px" border="0" cellspacing="0">

<tr align="left" valign="top">
<td width="50%">
[[image:MultiSurface-01a.png|300px]]
</td>
<td width="50%">
[[image:MultiSurface-01a.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td width="50%">
[[image:MultiSurface-Explode-01a.png|300px]]
</td>
<td width="50%">
[[image:MultiSurface-Explode-01b.png|300px]]
</td>
</tr>

<tr align="left" valign="top">
<td colspan="2">
'''Figure 11:''' Modeling overlapping roof parts ('''above:''' complete models, polygons outlined; '''below:''' roof polygons exploded)

'''Please note:''' the left model in Figure 11 is created with a MultiSurface element containing 7 polygons. However, the polygons do not represent a valid boundary of a rigid body. Calculating a volume is not possible. The right model is the same building geometry but modeled with 1 Solid element (7 polygons) and 1 MultiSurface element (2 polygons F6 and F8) as recommended (see CityGML Standard v1.0,p.61)

</td>
</tr>
</table>

== <span id="CompositeSurface"> [http://www.schemacentral.com/sc/niem21/e-gml32_CompositeSurface.html gml:CompositeSurface]</span>==

Eine CompositeSurface ist eine Menge <math>C=\lbrace S_1,S_2,...,S_n \rbrace</math> von Polygonen, für die
folgendes gilt:

# Die Schnittmenge zweier Polygone <math>S_k</math> und <math>S_l</math> aus <math>C</math> ist entweder leer oder besteht nur aus Punkten und/oder Kanten, die auch in den beiden linearen Ringen vorkommen. Bezeichne <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math> den planaren linearen Ring, der das Polygon <math>S</math> definiert. Dann gilt:<br><math>S_i \cap S_k= \begin{cases}\emptyset\\ \lbrace Q_0,Q_1,...,Q_m\rbrace,Q_j=P_k^i\\ \lbrace e_0,e_1,...,e_m\rbrace,e_j=\overline{P_i^kP_{i+1}^k} \end{cases}</math>
# Jede Kante <math>e_k=\overline{P_i^kP_{i+1}^k}</math> eines linearen Rings <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math> , der ein Polygon <math>S_k \in C</math> definiert, wird höchstens einmal als Kante <math>e_l=\overline{P_j^lP_{j+1}^l}</math> in einem linearen Ring <math>R_l=(P_0^l,P_1^l,...,P_m^l)</math> genutzt, der ein anderes Polygon <math>S_l \in C</math> definiert.<br>Es gilt <math>P_i^k=P_{j+1}^l</math> und <math>P_{i+1}=P_j^l</math>.
# Die Polygone aus <math>C</math> sind so orientiert, dass die Flächennormale benachbarte Polygone in dieselbe Richtung zeigen.
# Die Vereinigung aller Polygone aus <math>C</math> ohne die Kanten oder Punkte, in denen sich die Polygone berühren, ist isomorph zu einem Polygon.

Aus (1) und (2) ergibt sich, dass die Oberfläche, die durch <math>C</math> beschrieben wird, keine sich gegenseitig überlappenden oder durchdringenden Polygone enthalten darf (Polygone berühren sich höchstens in Punkten oder Kanten).

== <span id="Solid"> [http://www.schemacentral.com/sc/niem21/e-gml32_Solid.html gml:Solid]</span>==

A solid geometry represents a rigid body. The surface of the solid is defined by a set of polygons with the following properties.
The set <math>C=\lbrace S_1,S_2,...,S_n \rbrace</math> of polygons bounds a solid if:

# The intersection of two polygons <math>S_k</math> and <math>S_l</math> of <math>C</math> is either empty or contains only points <math>P</math> and edges <math>e</math> that are part of both Linear Rings. The polygon <math>S</math> is defined by the Linear Ring <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math>. The intersection of <math>S_k</math> and <math>S_l</math> equals: <br><math>S_i \cap S_k= \begin{cases}\emptyset\\ \lbrace Q_0,Q_1,...,Q_m\rbrace,Q_j=P_k^i\\ \lbrace e_0,e_1,...,e_m\rbrace,e_j=\overline{P_i^kP_{i+1}^k} \end{cases}</math>
# Every Edge <math>e_k=\overline{P_i^kP_{i+1}^k}</math> of a Linear Ring <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math> , defining a polygon <math>S_k \in C</math>, is used exactly once as an edge <math>e_l=\overline{P_j^lP_{j+1}^l}</math> in a Linear Ring <math>R_l=(P_0^l,P_1^l,...,P_m^l)</math>, defining another polygon <math>S_l \in C</math> with <math>P_i^k=P_{j+1}^l</math> and <math>P_{i+1}=P_j^l</math>.
# All polygons in <math>C</math> are oriented such that the normal vector of each polygon points to the outside of the solid.
# All polygons in <math>C</math> are connected, that is the dual graph of <math>C</math> has a path containing all nodes. The dual graph G<sub>C</sub> =(V<sub>C</sub>, E<sub>C</sub>) of <math>C</math> consists of a set V<sub>C</sub> of nodes and a set E<sub>C</sub> of edges. Every node v of V<sub>C</sub> represents exactly one polygon of <math>C</math>. An edge shared by two polygons <math>S_k</math> and <math>S_l</math> of <math>C</math> is represented by an edge <math>e=(v_{s_k},v_{s_l})</math> in E<sub>C</sub>.
# For every point <math>P</math> of a Linear Ring of a polygon of <math>C </math> applies: The graph <math>G_P =(V_P, E_P)</math>, that is only build by polygons and edges that touch<math>P</math> is connected. Each node <math>v</math> of <math>V_P</math> represents a polygon which Linear Ring contains <math>P</math>. Two nodes are connected by an edge <math>e</math> of <math>E_P</math> if the two polygons represented by the nodes have a common edge that touches <math>P</math>.

It follows from (i) and (ii) that the surface defined by <math>C</math> has no holes. Together with conditions (4) and (5) it follows that the inner of the solid defined by <math>C</math> is connected
<math>S</math> is denoted as closed [http://www.schemacentral.com/sc/niem21/e-gml32_CompositeSurface.html '''CompositeSurface'''].

'''Beispiele:'''

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:Solid-Fall-01.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-02.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-03.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-04.png|200px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="top">
Korrekt: 6 Flächen, geschlossen, Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Korrekt: 11 Flächen, geschlossen, Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Korrekt: 10 Flächen, geschlossen, Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Korrekt: 30 Flächen, geschlossen, Flächenorientierung korrekt
</td>
</tr>
</table>

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:Solid-Fall-05.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-06.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-07.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-08.png|200px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="top">
Nicht Korrekt: 5 Flächen, nicht geschlossen, Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Nicht Korrekt: 6 Flächen, geschlossen, Flächenorientierung nicht korrekt
</td>
<td width="300px" valign="top">
Nicht Korrekt: 12 Flächen, nicht geschlossen (zwei Außenhüllen), Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Nicht Korrekt: 12 Flächen, nicht geschlossen (innere und äußere Hülle), Flächenorientierung korrekt
</td>
</tr>
</table>

== <span id="CompositeSolid">[http://www.schemacentral.com/sc/niem21/e-gml32_CompositeSolid.html gml:CompositeSolid]</span>==
Ein CompositeSolid wird durch eine nichtleere Menge <math>C = \{S_1,..., S_n\}</math> von '''[[#Solid|Solids]]''' (vgl. 12.) beschrieben, für die gilt:

# Der Schnitt der Inneren zweier Solids <math>S_i</math>, <math>S_j</math>, 1 ≤ i ≤ n, 1 ≤ j ≤ n, i ≠ j, ist leer, d.h. entweder sind beide Solids <math>S_i</math>, <math>S_j</math> disjunkt oder beide berühren sich nur in Flächen, Linien oder Punkten
# Sei <math>C'</math> die Vereinigung aller Solids aus <math>C</math>. Dann ist die Begrenzung von <math>C'</math> (die Oberfläche von <math>C'</math> ohne die Flächen oder Punkte, in denen sich die Solids berühren) die Begrenzung eines Solid.

In CityGML werden bei CompositeSolids ebenso wie bei Solids innere Einschlüsse (Hohlräume) nicht betrachtet.

'''Examples:'''

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:CompositeSolid-01-Fall01.png|300px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall02.png|220px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall03.png|240px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall04.png|260px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="bottom">
correct; surface contact
</td>
<td width="300px" valign="bottom">
correct; surface contact
</td>
<td width="300px" valign="bottom">
correct; surface contact
</td>
<td width="300px" valign="bottom">
correct; surface contact
</td>

</tr>

</table>

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:CompositeSolid-01-Fall05.png|260px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall06.png|260px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall07.png|280px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall08.png|180px]]
</td>

</tr>

<tr align="middle">

<td width="300px" valign="bottom">
not correct; line contact
</td>
<td width="300px" valign="bottom">
not correct; point contact
</td>
<td width="300px" valign="bottom">
not correct; no contact at all
</td>
<td width="300px" valign="bottom">
not correct; intersection
</td>

</tr>

</table>

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:CompositeSolid-01-Fall14.png|220px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall14a.png|220px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall14b.png|220px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="bottom">
not correct; 26 boxes with surface contact
</td>
<td width="300px" valign="bottom">
but with internal hollow space
</td>
<td width="300px" valign="bottom">
not correct; interior boundaries
</td>

</tr>

</table>

== <span id="Triangle">[http://www.schemacentral.com/sc/niem21/e-gml32_Triangle.html gml:Triangle]</span> ==
* A Triangle is a special case of a polygon that is bounded by one outer Linear Ring with four points.
* There are no interior rings (no element "interior").

== <span id="TriangulatedSurface">[http://www.schemacentral.com/sc/niem21/e-gml32_TriangulatedSurface.html gml:TriangulatedSurface]</span> ==
A triangulated surface is a [[#CompositeSurface|CompositeSurface]] that consists of triangles only, but is not closed (it may have boundaries). There is no restriction on how the triangulation is derived.

== <span id="TIN">[http://www.schemacentral.com/sc/niem21/e-gml32_Tin.html gml:Tin] </span>==
In contrast to a gml:TriangulatedSurface, the triangles of a gml:TIN are not represented explicitly, but by its three vertices (called control points). In addition, breaklines, stop lines and the maximal length of a side of a triangle can be represented in a gml:TIN.

# A TIN is a triangulated surface that is the result of the application of a Delaunay Algorithm or of a similar algorithm (extended by breaklines, stop lines and the maximal length of a side of a triangle). The surface satisfies the Delaunay criterion:
## For each triangle in the network, the circle passing through its vertices does not contain, in its interior, the vertex of any other triangle.
# Stoplines are lines where the local continuity or regularity of the surface is questionable. In the area of these pathologies, triangles intersecting a stopline shall be removed from the TIN surface, leaving holes in the surface. If triangles incident to the boundary of the surfaces are removed, the boundary of the surfaces changes.
# Breaklines are lines that are critical for the shape of the surface, representing local ridges, or depressions (such as drainage lines) in the surface. As such their constituent segments must be included in the TIN even if doing so violates the Delaunay criterion.
# Areas of the surface where the data is not sufficiently dense to assure reasonable calculations shall be removed by adding a retention criterion for triangles based on the length of their sides. For any triangle sides exceeding maximum length, the adjacent triangles to that triangle side shall be removed from the surface. # The number of control points is at least three.
# The surface is not affected by the order in which the control points are given. Application schemas may add information based on the ordering of the control points to facilitate the reconstruction of the TIN from the control points.

Modeling Guide for 3D Objects - Part 2: Modeling of Buildings (LoD1, LoD2, LoD3)

2014-05-07T06:45:17Z

Egbert Casper: /* Document History */

{{TOC limit|4}}
== Document History ==

<table border="1" cellspacing="0">
<tr align="left" valign="top">
<th width="220">
Version
</th>
<th width="220">
Datum
</th>
<th width="220">
Autor/en
</th>
<th width="220">
Status
</th>
<th width="220">
Bemerkungen
</th>
</tr>
<tr align="left" valign="top">
<td>
0.8.0
</td>
<td width="220">
Januar 2012
</td>
<td>
</td>
<td bgcolor="#ff7777">
nicht öffentlich
</td>
<td>
Erste Versuche
</td>
</tr>
<tr align="left" valign="top">
<td>
0.9.0
</td>
<td width="220">
April 2012
</td>
<td>
</td>
<td bgcolor="#ff7777">
nicht öffentlich
</td>
<td>
Fertigstellung von Kapitel 1-4.1; 4.2 wird später bearbeitet
</td>
</tr>
<tr align="left" valign="top">
<td>
1.0.0
</td>
<td width="220">
Mai 2012
</td>
<td>
SIG 3D / AG Qualität
</td>
<td bgcolor="#73ff73">
öffentlich
</td>
<td>
Erste öffentliche Version von Kapitel 1-4.1;
</td>
</tr>
<tr align="left" valign="top">
<td>
1.1.0
</td>
<td width="220">
Januar/Februar 2013
</td>
<td>
SIG 3D / AG Qualität
</td>
<td bgcolor="#ff7777">
nicht öffentlich
</td>

<td>
Vorbereitung Version 2.0.0 mit Erweiterter Modellierung;
</td>
</tr>
<tr align="left" valign="top">
<td>
2.0.0
</td>
<td width="220">
März 2013
</td>
<td>
SIG 3D / AG Qualität
(c) 2013 Copyright Special Interest Group 3D (SIG3D) of the Spatial Data Infrastructure Germany (GDI-DE) http://www.sig3d.org
</td>
<td bgcolor="#73ff73">
öffentlich
</td>

<td>
Erste öffentliche Version mit Erweiterter Modellierung;
</td>
</tr>
<tr align="left" valign="top">
<td>
2.0.0 EN
</td>
<td width="220">
November 2013
</td>
<td>
SIG 3D / Quality Working Group
(c) 2013-2014 Copyright Special Interest Group 3D (SIG3D) of the Spatial Data Infrastructure Germany (GDI-DE) http://www.sig3d.org /EC, KHH
</td>
<td bgcolor="#73ff73">
public </td>

<td>
English version;
</td>
</tr>

</table>
-----
-----

== Introduction ==

=== Scope ===
* The modeling recommendations are usually independent from the recording method. That means that this document is '''not''' a recording manual.
* This document describes the modeling of 3D objects on the basis of '''existing information'''. In case of lacking information, in particular in case of missing height information, objects must '''explicitly not''' be modeled. For example, if all relevant information on balconies is available, this document provides recommendations for a standardized modeling. Otherwise balconies must not be modeled.
* Recommendations are related to the Open Geospatial Consortium (OGC) standard '''CityGML version 1.0 and 2.0'''.
* This document refers to '''national (German) and European standards''' (AdV, INSPIRE) and can only be partially generalized.
* This document is restricted to the '''outer shell''' of buildings, i.e. building modeling up to LoD3
-----
-----

=== Target Group===
* Modeler
* Data holder
* Developer
-----
-----

=== Prior Knowledge Required ===
* GML: Geography Markup Language
* CityGML: Application schema for GML for the representation, storage, and exchange of virtual 3D city and landscape models
* [[ALKIS]]: Official German Land Registry Information System
-----
-----

=== Further References ===
* [https://portal.opengeospatial.org/modules/admin/license_agreement.php?suppressHeaders=0&access_license_id=3&target=http://portal.opengeospatial.org/files/%3fartifact_id=28802 CityGML 1.0 Specification]

* [https://portal.opengeospatial.org/modules/admin/license_agreement.php?suppressHeaders=0&access_license_id=3&target=http://portal.opengeospatial.org/files/%3fartifact_id=47842 CityGML 2.0 Specification]

* [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)]]

* [http://www.adv-online.de/icc/extdeu/binarywriterservlet?imgUid=42b23fd2-1153-911a-3b21-718a438ad1b2&uBasVariant=11111111-1111-1111-1111-111111111111&isDownload=true GeoInfoDok V 6.0 - Modeling of the geoinformation of the official surveying and mapping of Germany (Main Document, in German only)]

* [http://www.adv-online.de/AAA-Modell/Dokumente-der-GeoInfoDok/binarywriterservlet?imgUid=c9e63fd2-1153-911a-3b21-718a438ad1b2&uBasVariant=11111111-1111-1111-1111-111111111111&isDownload=true ALKIS feature catalogue with building information ( in German only)]
-----
-----

=== Document Conventions ===
* '''Features''' are written in ''italic characters'' with the corresponding name space in ''' ''bold characters'' '''.
* '''Examples''' are written in <tt>fixed width</tt>.
* '''Online references''' to other internal or external pages and documents are written in <span style="color:blue;">blue</span>.
* A statement which is not valid for all '''Levels of Detail''' (LoD) is noted as (LoD[1234][+]), e.g. a notation with (LoD1) is only valid for LoD1, a notation (LoD2+) is valid for all LoDs from LoD2 and above.
-----
-----

== Definitions und Determinations ==

=== Level of Detail (Building, BuildingPart)===

'''Definitions of SIG 3D:'''
* LoD0
** For every building or building part the footprint or roof outline is represented by a horizontal polygon with a well defined absolute and constant height.
* LoD1
** For every building or building part the generalized outer shell is represented by exactly one prismatic extrusion solid. Ground, floor and roof surfaces must be horizontal, lateral boundary surfaces must be vertical.
* LoD2
** For every building or building part the geometrically simplified outer shell is represented by horizontal resp. vertical outer surfaces and simplified roof shapes. All kind of surfaces ( e.g. ground surfaces, wall surfaces, roof surfaces, outer ceiling surfaces, outer floor surfaces, virtual closure surfaces ) and additional building elements ( e.g. building installations like balkonies, dormers and chimneys ) may be represented as semantic objects.
* LoD3
** For every building or building part the geometrically detailed outer shell is represented by detailed outer surfaces and detailed roof shapes. All kind of surfaces ( e.g. ground surfaces, wall surfaces, roof surfaces, outer ceiling surfaces, outer floor surfaces, virtual closure surfaces ) and additional building elements ( e.g. building installations like balkonies, dormers and chimneys ) may be more detailly represented as semantic objects. In respect to LoD2 doors and windows can be modeled as planar thematic objects.
* LoD4
** For every building or building part the geometrically detailed outer shell and interior is represented by detailed outer and inner surfaces and detailed roof shapes. All kind of surfaces ( e.g. ground surfaces, inner and outer wall surfaces, inner and outer roof surfaces, outer ceiling surfaces, outer floor surfaces, virtual closure surfaces ) and additional movable and non movable building elements ( e.g. building installations like balconies, dormers, chimneys, interior and furniture ) may be represented with greater detail as semantic objects.
-----

=== Reference Coordinate System ===
CityGML 2.0 strongly recommends the specification of a reference coordinate system. For a meaningful use of data a valid reference coordinate system is imperative, therefore a valid reference coordinate system must be defined for each instance file:

* A reference coordinate system must be defined as '''three dimensional''' (usually position and height reference system --> [[Definitionen#CCRS|see Compound Coordinate Reference System]]).
* A reference coordinate system should '''not''' be changed within an instance file.
* A reference coordinate system should be defined once within <tt><gml:Envelope></tt>.

'''Recommendations for Germany:''' ''ETRS89 / UTM / Reference ellipsoid GRS80 + DHHN92''

'''CityGML Example:'''

<tt>
<gml:boundedBy>
<gml:Envelope srsDimension="3" srsName="'''urn:adv:crs:ETRS89_UTM32*DE_DHHN92_NH'''">
'''--> [[Definitionen#CCRS|see Compound Coordinate Reference System]]'''
<gml:lowerCorner srsDimension="3">458868.0 5438343.0 112.0 </gml:lowerCorner>
<gml:upperCorner srsDimension="3">458892.0 5438362.0 117.0 </gml:upperCorner>
</gml:Envelope>
</gml:boundedBy>
</tt>

'''ALKIS Example:'''

<tt>
<gml:boundedBy>
<gml:Envelope srsName="'''urn:adv:crs:ETRS89_UTM32'''">
<gml:pos>367456.554 5718128.391</gml:pos>
<gml:pos>367505.094 5718091.143</gml:pos>
</gml:Envelope>
</gml:boundedBy>
</tt>

see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#Spatial-Reference-System|Modeling Guide for 3D Objects - Part 1]]
-----
-----

=== <span id="ModelStructure">Model Structure</span> ===

The use of ''core:CityModel'' is not regulated explicitly in the specification and in the schema. The multiple use of ''core:CityModel'' is compliant to the schema and will be validated.
In order to avoid conflicts while importing CityGML models, it is recommended to use '''exactly one''' instance of ''core:CityModel'' as '''root element'''.

-----
-----

=== <span id="Heights">Heights</span> ===
The ''measuredHeight'' is the '''measured''' or '''computed''' difference between the lowest terrain intersection point and the highest roof point with the following properties:

* the ''measuredHeight'' is a '''simple''' attribute and so can not be specified and/or qualified any further;
* the ''measuredHeight'' is '''always''' related to the '''real''' building;
* the ''measuredHeight'' is '''independent of the LoD''' of the building;
* the '''computation''' of the ''measuredHeight'' should always base on the terrain model with the '''highest available resolution'''.

The following heights are valid for flat roofs, outshot roofs, gable roofs, hip roofs, jerkinhead roofs, mansard roofs, pyramid roof, shed roof, shells and domes:

[[image:Höhenangaben-01.png|800px]]

The following heights are valid for all kind of shed roofs:

[[image:Höhenangaben-02.png|800px]]

The following heights are valid for different roof overhangs:

[[image:Höhenangaben-03.png|800px]]

If absolute heights for the noted values are needed, they have to be defined as generic attributes (dimensioned ''gen:measureAttribute''):
* ''<gen:measureAttribute name="min height surface"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
* ''<gen:measureAttribute name="min height eaves"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
* ''<gen:measureAttribute name="max height eaves"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
* ''<gen:measureAttribute name="max height ridge"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
-----
-----

=== <span id="TerrainIntersectionLine">Terrain Intersection Line</span> ===
In CityGML the terrain intersection line is an attribute of a building or building part. It is generated by intersection of the building or building part with the terrain and has the following properties:

* a terrain intersection line can be '''measured''' or '''calculated''' ;
* if a terrain intersection line is calculated, the terrain model with the '''highest resolution available''' should be used;
* a terrain intersection line is an '''attribute''' of the '''building or building part''';
* outer building installations (''bldg:BuildingInstallation'') are '''taken into account''' from a terrain intersection line (see '''Figure A''');
* a terrain intersection line is a result of the intersection of buildings in the respective LoD and the most accurate available terrain. In CityGML it has no relation to the terrain used in a visualization and its resolution and accuracy.
* a terrain intersection line may consist of '''several independent parts''';
* a terrain intersection line '''need not be closed''';
* a terrain intersection line which does not exist in reality will '''not be taken into account''' (e.g. in the case of building parts ).
<table width="800px" border="0" cellspacing="6">
<tr align="middle">
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall a.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall b.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall c.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall d.png|200px]]
</td>
<tr align="middle" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
<td>
Figure C
</td>
<td>
Figure D
</td>
</tr>

</table>
-----
-----

=== <span id="AuskragendeBauelemente">Overhanging Building Elements</span> ===
Overhanging or projecting building elements are defined as '''parts''' of roofs, walls etc, which should '''not be considered in the volume calculation of the building'''. Overhanging or projecting building elements are modeled as follows:
* always as from the volume-forming building element separated surface element(s) (see '''Figure A''')
* always as a surface element, if the thickness of the building element is less than 0.5 m (see '''Figure B''')
* always as a solid element, if the thickness of the building element is greater than 0.5 m (see '''Figure B''')
* in LoD2 always as a surface element, if the thickness of the building element is less than 0.5 m
* in LoD2 always as a solid element, if the thickness of the building element is greater than 0.5 m
* in LoD3 always in the best accuracy based on available information.


<table border="0" cellspacing="0">
<tr align="left" valign="center">
<td width="800">
[[image:AuskragendeBauelemente-1.png|800px]]
</td>
</tr>
<tr align="middle" valign="top">
<td width="500">
Figure A
</td>
</tr>
</table>

<table border="0" cellspacing="0">
<tr align="middle" valign="top">
<td width="500">
[[image:AuskragendeBauelemente-2.png|500px]]
</td>
</tr>
<tr align="middle" valign="top">
<td>
Figure B
</td>
</tr>
</table>

-----
-----

=== <span id="ClosedCoverageType"> Closed Coverage Type</span> ===
Buildings as parts of closed coverage type (applies to semi-detached and terrace houses also) can be modeled as follows:
* Buildings that are '''separated within the land register''' should be modeled as '''separate buildings'''.
<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="400">[[image:GeschlosseneBauweise-01-V01.png|400px]]</td><td width="400">[[image:GeschlosseneBauweise-04-V01.png|400px]]</td></tr><tr align="left" valign="center"><td width="400">Separate buildings of closed coverage type</td><td width="400">Terrace houses as separate buildings</td></tr></table>
* Buildings that are '''united within the land register''' should be modeled as '''one single building''' which can be subdivided into building parts (e.g. row of buildings, semi-detached or terrace houses).
<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="400">[[image:GeschlosseneBauweise-02-V01.png|400px]]</td><td width="400">[[image:GeschlosseneBauweise-03-V01.png|400px]]</td></tr><tr align="left" valign="center"><td width="400">Terrace houses as one single building</td><td width="400">Terrace houses as building parts</td></tr></table>
* Buildings '''without any land register information''' and for which the building detection provides '''no usable structures''' (e.g. based on flights) should be modeled as '''one single building'''.<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="400">[[image:GeschlosseneBauweise-02-V01.png|400px]]</td></tr><tr align="left" valign="center"><td width="400">Terrace houses as one single building</td></tr></table>

The modeling of '''boundary surfaces''' between buildings must satisfy the following geometric resp. semantic conditions:
* Common boundary surfaces may only '''be referenced within a building via Xlink''' (building-building part resp. building part - building part).

-----
-----

=== <span id="Addresses">Addresses</span> ===
* The CityGML specification allows to assign an address both to a building (''bldg:Building'', ''bldg:BuildingPart'') as well as to a door (''bldg:Door''). It is recommended '''always to assign an address to a building''' (in any LoD) because doors are not available in LoD1 and LoD2.

* It is recommended to use the complete '''postal address'''.

* '''Multiple addresses''' can be assigned to one building.

* '''Umlauts''' are allowed in addresses (z.B. <span style="color:#008000">Würzburg☺</span>, <span style="color:#008000"> Wuerzburg☺</span>, <span style="color:#FF0000">Würzburg and Wuerzburg mixed ☹</span>).

'''General example:'''

Street: Hermann-von-Helmholtz-Platz
Number: 1
Zip Code: 76344
City: Eggenstein-Leopoldshafen

'''CityGML example:'''

<core:Address>
<core:xalAddress>
<xAL:AddressDetails>
<xAL:Locality Type="Town">
<xAL:LocalityName>'''Eggenstein-Leopoldshafen'''</xAL:LocalityName>
<xAL:Thoroughfare Type="Street">
<xAL:ThoroughfareNumber>'''1'''</xAL:ThoroughfareNumber>
<xAL:ThoroughfareName>'''Hermann-von-Helmholtz-Platz'''</xAL:ThoroughfareName>
</xAL:Thoroughfare>
<xAL:PostalCode>
<xAL:PostalCodeNumber>'''76344'''</xAL:PostalCodeNumber>
</xAL:PostalCode>
</xAL:Locality>
</xAL:AddressDetails>
</core:xalAddress>
</core:Address>
-----
-----

=== Codelists ===
Codelists for the CityGML 2.0 standard are available at "http://www.sig3d.org/codelists/standard".

The recommendations for codelists in this modeling guide refer to the proposal of the SIG3D. These codelists are availabe (in German only) at "http://www.sig3d.org/codelists/Handbuch-SIG3D" and relate to ALKIS.

This modeling guide refers to the following codelists:

*Building resp. building part (''bldg:Building / bldg:BuildingPart'')
**class http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_class.xml
**function http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_function.xml
**usage http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_usage.xml
**roofType http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_roofType.xml

*Building installations (''bldg:BuildingInstallation'')
**function http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml

-----
-----

=== Generic Attributes ===
Generic (user defined) attributes may be used to represent attributes which are '''not covered explicitly by the CityGML schema'''. Generic attributes must be used with care; they shall only be used if there is no appropriate attribute available in the overall CityGML schema. Otherwise, problems concerning semantic interoperability may arise. Interoperability of generic attributes is '''reduced to attribute values''' which can only be interpreted semantically by additional information.
The following attribute types are defined:

* ''stringAttribute'' - for arbitrary strings
* ''intAttribute'' - for dimensionless integer numbers
* ''doubleAttribute'' - for dimensionless floating point numbers
* ''dateAttribute'' - for dates with integer-valued year, month and day representation in the format YYYY-MM-DD (e.g. 2013-03-08)
* ''uriAttribute'' - represents a Uniform Resource Identifier Reference (URI) (e.g. a link to a document or a web site)
* ''measureAttribute'' - for dimensioned values (CityGML 2.0)

Attributes can be combined in CityGML 2.0 by generic attribute sets '''''genericAttributeSet''''' with an optional '''''codeSpace'''''. If the '''''codeSpace''''' attribute is present, then its value should identify an authority for the set, such as the organisation or community who defined its content. The generic attribute set may contain arbitrary generic attributes.

'''CityGML Examples'''

<gen:stringAttribute name="'''construction'''"><gen:value>'''concrete'''</gen:value></gen:stringAttribute>
<gen:intAttribute name="'''entries'''"><gen:value>'''3'''</gen:value></gen:intAttribute>
<gen:doubleAttribute name="'''floor area ratio FAR'''"><gen:value>'''0.33'''</gen:value></gen:doubleAttribute>
<gen:dateAttribute name="'''approval date'''"><gen:value>'''2012-03-09'''</gen:value></gen:dateAttribute>
<gen:uriAttribute name="'''website '''"><gen:value>'''http://www.sig3d.org'''</gen:value></gen:uriAttribute>
<gen:measureAttribute name="'''building width'''"><gen:value uom="#'''m'''">'''10.00'''</gen:value>/gen:measureAttribute>

<gen:genericAttributeSet name="'''Base Quantities'''">
<gen:measureAttribute name="Height"><gen:value uom="#m">9.00</gen:value></gen:measureAttribute>
<gen:measureAttribute name="Area"><gen:value uom="#m2">80.00</gen:value></gen:measureAttribute>
<gen:measureAttribute name="Volume"><gen:value uom="#m3">720.00</gen:value></gen:measureAttribute>
</gen:genericAttributeSet>
-----
-----

=== Geometry ===

There is '''no GML Profile''' for CityGML. This means that CityGML instance files will validate with every GML geometry. The specification '''restricts''' the usage of GML geometry classes (CityGML 2.0 Annex D "Overview of employed GML3 geometry classes).
CityGML references to the following geometry classes ('''CityGML 2.0 Annex D'''):

<table width="1200px" border="1" cellspacing="0">
<tr align="left">
<td width="250px">
'''Abstract Classes'''
</td>
<td width="250px">
'''Instantiated Classes'''
</td>
<td width="700px">
'''Further Limitations'''
</td>
</tr>
<tr>
<td width="250px" rowspan="2">
''gml:_Solid''
</td>
<td width="250px">
''gml:'''Solid'''''
</td>
<td>
only ''gml:OrientableSurface'', ''gml:Polygon'', ''gml:CompositeSurface'',

''tex:TexturedSurface'' (obsolete)
</td>
</tr>
<tr>
<td>
''gml:'''CompositeSolid'''''
</td>
<td>
no restriction
</td>
</tr>

<tr>
<td rowspan="6">
''gml:_Surface''
</td>
<td>
''gml:'''Polygon'''''
</td>
<td>
only ''gml:'''LinearRing''''' and ''gml:'''Ring''''' exclusively with ''gml:LineString'' or ''gml:CompositeCurve''
</td>
</tr>
<tr>

<td>
''gml:'''OrientableSurface'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>

<td>
''tex:TextureSurface''
</td>
<td>
obsolete
</td>
</tr>
<tr>

<td>
''gml:'''CompositeSurface'''''
</td>
<td>
only ''gml:OrientableSurface'', ''gml:Polygon'', ''gml:CompositeSurface''

''tex:TexturedSurface'' (veraltet)
</td>
</tr>
<tr>

<td>
''gml:'''TriangulatedSurface'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>

<td>
''gml:'''Tin'''''
</td>
<td>
no restriction
</td>
</tr>

<tr>
<td rowspan="2">
''gml:_Curve''
</td>
<td>
''gml:'''LineString'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>
<td>
''gml:'''CompositeCurve'''''
</td>
<td>
''gml:LineString'' and ''gml:CompositeCurve'' only
</td>
</tr>
<tr>
<td>
''gml:_GeometricPrimitive''
</td>
<td>
''gml:'''Point'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>

<td>
''gml:_Coverage''
</td>
<td>
''gml:'''RectifiedGridCoverage'''''
</td>
<td>
no restriction
</td>
</tr>


<tr>
<td rowspan="6">
''gml:_AbstractGeometricAggregate''
</td>
<td>
''gml:'''MultiSolid'''''
</td>
<td>
no restriction
</td>

</tr>
<tr>
<td>
''gml:'''MultiSurface'''''
</td>
<td>
only ''gml:OrientableSurface'', ''gml:Polygon'', ''gml:CompositeSurface'',

''tex:TexturedSurface'' (obsolete)
</td>
</tr>
<tr>
<td>
''gml:'''MultiCurve'''''
</td>
<td>
only ''gml:LineString'' and ''gml:CompositeCurve''
</td>
</tr>
<tr>
<td>
''gml:'''MultiPoint'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>
<td>
''gml:'''GeometricComplex'''''
</td>
<td>
restricted to connected linear networks
</td>
</tr>
<tr>
<td>
''gml:'''MultiGeometry'''''
</td>
<td>
restrictrions see allowed geometry types
</td>

</tr>

</table>

In order to keep the instance files small and to ensure an optimal editability of models, maximum flat polygons should be used, if appropriate with holes (inner rings).

-----
-----

=== File Name ===
It is recommended to use *.gml as file extension to distinguish CityGML files from other XML files.
-----
-----

== Modeling ==

=== Base Modeling ===
The base modeling includes the modeling of the '''building resp. building part''' itself in LoD1, with appropriate '''boundary surfaces''' in LoD2 and LoD3 and with '''windows and doors''' in LoD3. In addition, the basic modeling covers the general use of '''building installations'''.
-----
-----
==== <span id="Building">Building (''bldg:Building'')</span> ====

===== Definition =====
'''SIG3D:''' A free-standing self-supporting construction that is roofed, usually walled, and can be entered by humans and is normally designed to stand permanently in one place. It is intended for human occupancy (for example: a place of work or recreation), habitation and/or shelter of humans, animals or things.

'''ISO:''' Provision of shelter for its occupants or contents as one of its main purposes; usually partially or totally enclosed and designed to stand permanently in one place

===== CityGML Feature =====
''bldg:Building''

===== Geometry =====
'''''gml:Solid''''' see [[Handbuch für die Modellierung von 3D Objekten - Teil 1: Grundlagen (Regeln für valide GML Geometrie-Elemente in CityGML)#gml:Solid| Modeling Guide - Part 1]]

It is recommended to use '''''gml:Solid''''' depending on the LoD in the following way :

*In LoD1 a solid directly contains the bounding geometry ('''Figure A''')
*In LoD2 and LoD3 a solid contains external references (Xlinks) to the bounding geometry ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer bottom surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]] as well as [[#Türen|doors]] and [[#Fenster|windows]]) ('''Figure B''') ( see also conformance requirement no. 4 in chapter 10.3.9 of the CityGML V2.0 specification )


<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="400">
[[image:BuildingSolid-V1.png|300px]]
</td>
<td width="400">
[[image:BuildingSolidXlink.png|350px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
</tr>
</table>

'''''gml:MultiSurface''''' ''' <span style="color:#FF0000">(not recommended)</span>'''

'''''gml:MultiCurve''''' '''<span style="color:#FF0000">(not recommended)</span>'''

===== <span id="BuildingAttributes">Attributes</span> =====
; ''gml:id'' <span style="color:#008000">(mandatory)</span>
: from GML version 3.2 onwards an id is mandatory
; ''gml:name'' <span style="color:#00FF00">(recommended, if available in the underlying land register)</span>
:'name' is the proper name or the name of the building.
; ''bldg:class'' (LoD1, LoD2, LoD3)
:The attribute ''bldg:class'' allows an unspecified classification of the building; no suggestion from the SIG3D;
; ''bldg:function'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:The 'function' of a building is the predominantly functional significance of the building at the date of data collection ( principle of dominance ); see also in the SIG3D code lists.
; ''bldg:usage'' (LoD1, LoD2, LoD3) <span style="color:#0000FF">(conditionally recommended)</span>
:The 'usage' of a building describes the use of the building and contains the respective percentage usage share of the total use.
; ''bldg:yearOfConstruction'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:The 'yearOfConstruction' is the year of completion of the construction or alteration of the building;
; ''bldg:yearOfDemolition'' (LoD1, LoD2, LoD3)
:The 'yearOfDemolition' is the year of deconstruction of the building;
;''bldg:roofType'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:'Roof type' describes the characteristic shape of the roof; see also in the code list of the SIG3D
; ''bldg:measuredHeight'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:'Measured height' is the difference in [m] between the highest point of the roof structure and the defined footprint of the building; see also [[#Heights|Heights]]
; ''bldg:storeysAboveGround'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended, if available in the underlying land register)</span>
:'storeys above ground' is the number of above-ground floors
; ''bldg:storeysBelowGround'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended, if available in the underlying land register)</span>
:'storeys below ground' is the number of underground floors
; ''bldg:storeysHeightsAboveGround'' (LoD1, LoD2, LoD3)
:Height between two consecutive floors of the above-ground floors
; ''bldg:storeysHeightsBelowGround'' (LoD1, LoD2, LoD3)
:Height between two consecutive floors of the underground floors
; ''bldg:lodXSolid'' (LoD1, LoD2, LoD3)
:LoDX geometry (volume)of the building
; ''bldg:lodXMultiSurface'' (LoD1, LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:LoDX geometry (surface) of the building
; ''bldg:lodYMultiCurve'' (LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:LoDY geometry (curve) of the building
; ''bldg:lodXTerrainIntersection'' (LoD1, LoD2, LoD3)
:LoDX geometry (curve) of the [[#Terrain Intersection Line|terrain intersection line]] of the building
; ''bldg:outerBuildingInstallation'' (LoD2, LoD3)
:Relation to LoD2/LoD3 building installation
; ''bldg:boundedBy'' (LoD2, LoD3)
: Relation to boundary surfaces ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer floor surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]])
; ''bldg:consistsOfBuildingPart'' (LoD1, LoD2, LoD3)
:Relation to LoD1/LoD2/LoD3 building parts
; ''bldg:address'' (LoD1, LoD2, LoD3)
:Relation to one or more building addresses

===== Examples =====

<table width="1200px" border="0" cellspacing="6">
<tr align="left">
<td colspan="6">
'''Detached family house'''
</td>
</tr>
<tr align="middle">
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-real.png|200px]]
</td>

<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD0.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD1.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD2.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD3.png|200px]]
</td>
<tr align="middle" valign="top">
<td>
Real Building
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

</table>
-----
-----

==== <span id="Gebäude">Building Part (''bldg:BuildingPart'')</span> ====

===== Definition =====
'''SIG3D:''' A building part is a sub-division of a building that is homogeneous related to its physical, functional or temporal aspects and may be considered as a building.

The subdivision of a building can be done by different criteria, e.g.
* structural like number of floors, roof type, height, construction method,
* administrative like building function, ownership, year of construction.

Building parts (''bldg:BuildingParts'') must satisfy the following conditions ( necessary conditions ):
* A building part '''always''' has a relation (bldg:consistsOfBuildingPart) to '''exactly one''' building:
* Buildings and building parts '''touch each other''' planar or linear-shaped,
* Building parts must be '''"connected to ground"''' and can have the following '''properties''' ( for example, storeys are no building parts ):
** Building parts may have different '''building attributes''' ( e.g. function, roof type ),
** Building parts may have an address that '''differs''' from the address of the building,
** The geometry of building parts (''bldg:BuildingParts'') must be modeled in a way that both the '''volume''' and the '''surfaces''' of the boundary surfaces ( wall surfaces, roof surfaces and ground surfaces ) correspond to the real conditions ([[#BuildingPart/Geometry|see chapter Building Part/Geometry]]),
** If a building part is emphasized as the '''main part of the building''', its semantics and geometry can be modeled in the parent building,
** Building parts will not be subdivided into further building parts.

===== CityGML Feature =====

''bldg:BuildingPart''

===== <span id="BuildingPart/Geometry"> Geometry</span> =====
;'''''gml:Solid'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:Solid|Modeling Guide for 3D Objects - Part 1]]

:It is recommended to use '''''gml:Solid''''' depending on the LoD in the following way :

:*In LoD1 a solid directly contains the bounding geometry ('''Figure A''')
:*In LoD2 and LoD3 a solid contains external references (Xlinks) to the bounding geometry ([[#Wall Surface|wall surfaces]], [[#Roof Surface|roof surfaces]], [[#Ground Surface|ground surfaces]], [[#Outer Ceiling Surface|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer bottom surfaces]] and [[#Closure Surface|closure surfaces]] as well as [[#Doors|doors]] and [[#Windows|windows]]). '''Surfaces, which do not exist in reality''' are modeled as closure surfaces ('''Figure B''').
:*In LoD2 a solid contains external references (Xlinks) to the real bounding geometry. '''Surfaces, which do not exist in reality''' are modeled as closure surfaces and assigned directly to the building part ('''Figure C''').


<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD1.png|200px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-FallB.png|200px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-FallB.png|200px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD1-gedreht.png|300px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-gedreht-FallB.png|300px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-gedreht-FallC.png|300px]]
</td>
</tr>

<tr align="left" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
<td>
Figure C
</td>

</tr>
</table>

; ''bldg:boundedBy'' (LoD2, LoD3)
: Relation to boundary surfaces ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer floor surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]])

'''''gml:MultiSurface''''' ''' <span style="color:#FF0000">(not recommended)</span>'''

'''''gml:MultiCurve''''' '''<span style="color:#FF0000">(not recommended)</span>'''

===== <span id="BuildingAttribute">Attributes</span> =====
Since the building part is derived from the building, all attributes of the building are also available for the building part (see also [[#BuildingAttribute|Building Attribute]]).

'''Exception:''' ''bldg:consistsOfBuildingPart''

===== Examples =====
<table width="1100px" border="0" cellspacing="0">
<tr align="left">
<td>
'''Office with factory hall'''
</td>
<td>

</td>
</tr>
<tr align="left">
<td width="550px" valign="bottom">
[[image:Buero-Werkshalle-01.png|500px]]
</td>
<td width="550px" valign="bottom">

</td>

</tr>
<tr align="left">
<td>
"structurally distinct" building parts → "Office" as function of BuildingPart 1 ; "Factory Hall" as function of BuildingPart 2
</td>
<td>

</td>
</tr>
</table>

<table width="1100px" border="0" cellspacing="0">
<tr align="left">
<td>
'''Detached house with staggered shed roof'''
</td>
<td>
'''House with a projecting floor'''
</td>
</tr>
<tr align="left">
<td width="550px" valign="bottom">
[[image:FJK-Haus-BuildingParts.png|500px]]
</td>
<td width="550px" valign="bottom">
[[image:FJK-Haus-BuildingParts-03.png|500px]]
</td>

</tr>
<tr align="left">
<td>
No "structurally distinct" building parts → roofType "staggered shed roof"
</td>
<td>
No "structurally distinct" building parts; 1 building part not "connected to ground"
</td>
</tr>
</table>

'''Examples with overarching building parts'''

Variante 1
[[image:Variante-01-V2-red.png|500px]]

'''Variante 2'''
[[image:Variante-02-V1-red.png|500px]]

Variante 3
[[image:Variante-03-V2-red.png|500px]]

-----
-----

==== <span id="BuildingInstallation">Building Installations (''bldg:BuildingInstallation'')</span> ====

===== Definition =====
'''SIG3D:''' Permanently installed parts of the buildings outer shell which are accessory for the building structure including loggia, dormer, etc. Doors and windows are modeled by the corresponding CityGML classes.

===== CityGML Feature =====

*'''LOD1:''' not available
*'''LOD2:''' ''bldg:BuildingInstallation''
*'''LOD3:''' ''bldg:BuildingInstallation''

===== <span id="BuildingInstallation/Geometry"> Geometry</span> =====
;'''''gml:Geometry'''''
:'''''gml:Geometry''''' allows '''points''', '''lines''', '''areas''', '''volumes''' as well as any combination of these elements.
:The use of points is '''<span style="color:#FF0000">not recommended</span>'''. <br />
:The use of lines is only '''<span style="color:#0000FF">recommenced under certain circumstances</span>''', because not all applications are able to process this geometry.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:Haus-mit-Antenne-V1.png|300px]]
</td>
<td width="300">
[[image:Haus-mit-SolarPanel-V1.png|300px]]
</td>
<td width="300">
[[image:Haus-mit-Kamin-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
Lines (e.g. Antenna)
</td>
<td width="300">
Surfaces (e.g. Solar Panel)
</td>
<td width="300">
Volumes (e.g. Chimney)
</td>
</tr>
</table>

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:Haus-mit-SatellitenAntenne-V2.png|300px]]
</td>
<td width="300">
[[image:LoD2-Haus-Treppe-V2-MultiGeo-V1.png|300px]]
</td>
<td width="300">
[[image:Haus-mit-Balkon-V2.png|300px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
Lines and surfaces (e.g. satellite dish)
</td>
<td width="300">
Lines and surfaces resp. surfaces and volumes (e.g. stair and porch)
</td>
<td width="300">
Lines, surfaces und volumes (e.g. balcony)
</td>
</tr>
</table>

; ''bldg:boundedBy'' (LoD2, LoD3)
: Relation to boundary surfaces ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer floor surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]]) → see also [[#ErweiterteModellierung|Extended Modeling]]

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-Solid-V1.png|200px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-V1.png|320px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-Solid-V1-explode.png|200px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-V1-explode.png|320px]]
</td>
</tr>

<tr align="left" valign="center">
<td width="300">
Building with a small ridge turret (modeled as a building installation with geometry)
</td>
<td width="500">
Building with a tower (modeled as a building installation with boundary surfaces)
</td>
</tr>
</table>

===== <span id="BuildingInstallation/Attributes">Attributes</span> =====
; ''gml:id'' <span style="color:#008000">(mandatory)</span>
: from GML version 3.2 onwards an id is mandatory
; ''bldg:class'' (LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:The attribute ''bldg:class'' allows an unspecified classification of the building installation; no suggestion from the SIG3D;
; ''bldg:function'' (LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:The 'function' of a building installation is the predominantly functional significance of the building installation at the date of data collection ( principle of dominance ); see also in the SIG3D code lists.
; ''bldg:usage'' (LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:no suggestion from the SIG3D;
; ''bldg:lodXGeometry'' (LoD2, LoD3)
:LoDX geometry of the building installation;

===== <span id="BuildingInstallation/Examples">Examples</span> =====
<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-Solid-LOD1-V1.png|300px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-Solid-LOD2-V1.png|300px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-Solid-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
LoD1: no building installation
</td>
<td width="300">
LoD2: simplified building installation
</td>
<td width="300">
LoD3: detailed building installation
</td>
</tr>
</table>
<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-LOD1-V1.png|400px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-V1.png|400px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-LOD3-V1.png|400px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
LoD1: no building installation
</td>
<td width="300">
LoD2: simplified building installation
</td>
<td width="300">
LoD3: detailed building installation
</td>
</tr>
</table>

------
------

==== <span id="GroundSurfaces">Ground Surfaces (''bldg:GroundSurface'')</span> ====

===== Definition =====
'''SIG3D:''' Exterior, lower boundary surface of a building, building part or building installation against soil or water ( e.g. foundation ).

===== CityGML Feature =====

*'''LoD1:''' not available
*'''LoD2:''' ''bldg:GroundSurface''
*'''LoD3:''' ''bldg:GroundSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:Solid|Modeling Guide for 3D Objects - Part 1]]
* A '''ground surface''' consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.

[[image:GroundSurface-Flaech-Volumen.png|600px]]

* The '''elevation''' of the ground surface depends on the availability of data:
** If there is information available about cellars, the elevation of the ground surface is set to the lower edge of the floor of the cellar ('''Figure A''');
** If the ground surface of the building, building part or building installation is generated by an intersection with the terrain, the elevation of the (horizontal) ground surface is set to the lowest absolute height of the corresponding terrain intersection line ('''Figure B''');
** It is <span style="color:#FF0000">not recommeded</span> to generate the ground surface of the building, building part or building installation directly from an intersection with the terrain ('''Figure C''');


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:GroundSurface-Skizze-5-V2.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-Skizze-6-V2.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-Skizze-7-V2.png|250px]]
</td>
<tr align="left" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
<td>
Figure C
</td>
</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>

===== Attribute =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry of the base area
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry of the base area
;''bldg:opening'' <span style="color:#FF0000">not recommended</span>
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#Windows|windows]] ) )

===== Examples =====

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:GroundSurface-0-V1.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-1-V1.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-2-V1.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-3-V1.png|250px]]
</td>
<tr align="left" valign="top">
<td>
Building without cellar and one floor slab
(One bldg:GroundSurface)
</td>
<td>
Building with cellar and one floor slab
(One bldg:GroundSurface)
</td>
<td>
Building with partial cellar and two different floor slabs
(Two bldg:GroundSurface)
</td>
<td>
Building with cellar and ramp
(Two bldg:GroundSurface)
</td>
</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:GroundSurface-5-V2.png|250px]]
</td>
<td width="253">
[[image:GroundSurface-6-V2.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-7-V2.png|250px]]
</td>
<tr align="left" valign="top">
<td>
Building with ground surface at lower edge of floor cellar
(One bldg:GroundSurface)
</td>
<td>
Building with ground surface at lowest absolute height of the corresponding terrain intersection line
(One bldg:GroundSurface)
</td>
<td>
Building with ground surface based on intersection with the terrain
(One bldg:GroundSurface) <span style="color:#FF0000">not recommended</span>

</td>

</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>
-----
-----

==== <span id="WallSurfaces">Wall Surfaces (''bldg:WallSurface'')</span> ====

===== Definition =====
'''SIG3D:''' A wall surface is an exterior, lateral boundary surface of a building, building part or building installation.

'''ISO:''' A wall is a vertical construction that bounds or subdivides a space and usually fulfils a loadbearing or retaining function.

The normals of the wall surfaces should generally lie in the horizontal ( up to 45 degrees ).

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:WallSurface''
* '''LoD3:''' ''bldg:WallSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* A '''wall surface''' surface consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.

[[image:WallSurface-Flaechen-Volumen.png|600px]]

* '''Wall projections''', which do not limit the volume of the building will be modeled according to the rules for
'''[[#AuskragendeBauelemente|Cantilevered building elements]]'''.



* A '''wall surface''' ''must'' consist of '''several surfaces ( SurfaceMember )''' if :
** a wall surfaces has different '''colors''' or '''textures'''<table border="0" cellspacing="6"><tr align="left" valign="top"><td width="300">[[image:WallSurface-mit-Farben-V1.png|300px]]</td><td width="300">[[image:WallSurface-mit-Texturen-V1.png|300px]]</td><tr align="left" valign="top"><td>4 wall surfaces with 3 areas each (1 area in "orange"; 2 areas in "beige")(4 bldg:WallSurface)</td><td>4 wall surfaces with 2 areas each (1 area with texture "plaster"; 1 area with texture "sandstone") (4 bldg:WallSurface)</td></table>
** a wall surface is '''nonplanar'''<table border="0" cellspacing="6"><tr align="left" valign="top"><td width="300">[[image:WallSurface-Rund-V1.png|300px]]</td><td width="300">[[image:WallSurface-Laibungen-V1.png|300px]]</td><tr align="left" valign="top"><td>5 wall surfaces; 4 wall surfaces with 1 surface each and 1 wall surface (circular wall) with 6 surfaces (4 bldg:WallSurface)</td><td>Front wall as 1 wall surface consisting of 4 surfaces (revealing areas); right wall as 1 wall surface consisting of 13 surfaces (12 revealing areas)</td></table>
* A '''wall surface''' ''might'' consist of '''several surfaces ( SurfaceMember )''' if :
** it is intended to indicate a '''storey structure'''<table border="0" cellspacing="6"><tr align="left" valign="top"><td width="300">[[image:WallSurface-ohne-Stockwerke-V1.png|300px]]</td><td width="300">[[image:WallSurface-mit-Stockwerke-V1.png|300px]]</td><tr align="left" valign="top"><td>4 wall surfaces with 1 surface each (4 bldg:WallSurface)</td><td>4 wall surfaces with 3 surfaces each (ground floor, upper floor and top floor) (4 bldg:WallSurface)</td></table>

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry of the wall
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry of the wall
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#Windows|windows]] ) )

===== Examples =====
<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:WallSurface-0-V2.png|250px|link=WallSurface-0-Animation]]
</td>
<td width="250">
[[image:WallSurface-1-V2.png|250px|link=WallSurface-1-Animation]]
</td>
<td width="250">
[[image:WallSurface-2-V2.png|250px|link=WallSurface-2-Animation]]
</td>
<tr align="left" valign="top">
<td>
A wall surface with 4 surfaces
(1 bldg:WallSurface)
<span style="color:#FF0000">not recommended</span>
</td>
<td>
4 wall surfaces with 1 surface each
(4 bldg:WallSurface)
</td>
<td>
4 wall surfaces (3 planar walls with 1 surface each and 1 circular wall with 12 surfaces)
(4 bldg:WallSurface)
</td>
</tr>
</table>

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:WallSurface-3-V2.png|250px]]
</td>
<td width="250">
[[image:WallSurface-4-V2.png|250px]]
</td>
<tr align="left" valign="top">
<td>
1 wall surface with elliptic or circular layout
(1 bldg:WallSurface)
</td>
<td>
5 wall surfaces by staggered facades
(5 bldg:WallSurface)
</td>
</table>
-----
-----

==== <span id="RoofSurfaces">Roof Surfaces (''bldg:RoofSurface'')</span> ====

===== Definition =====
'''SIG3D:''' A roof surface is a exterior, upper boundary surface of a building, building part or building installation, whose primary function is to protect from the effects of weather.
'''ISO:''' A roof is a construction that encloses a building from above

The normals of a roof should generally lie in the vertical.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:RoofSurface''
* '''LoD3:''' ''bldg:RoofSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* A '''roof surface''' surface consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.

[[image:RoofSurface-Flaechen-Volumen.png|600px]]

* '''Roof projections''', which do not limit the volume of the building will be modeled according to the rules for '''[[#AuskragendeBauelemente|cantilevered building elements]]'''.

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry of the roof
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry of the roof
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Gable Roof'''
</td>
<td width="250">
'''Gable Roof'''
</td>
<td width="250">
'''Mixed Roof'''
</td>
<td width="250">
'''Tent Roof'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:RoofSurface-0-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-1-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-2-V1.png|220px]]
</td>
<td width="250">
[[image:RoofSurface-3-V1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 roof surface with 2 surfaces
(1 bldg:RoofSurface) <span style="color:#FF0000">not recommended</span>
</td>
<td>
2 roof surfaces with 1 surface each
(2 bldg:RoofSurface)
</td>
<td>
3 roof surfaces ( 2 planar roof surfaces with 1 surface each and 1 conical roof area with 12 surfaces )
(3 bldg:RoofSurface)
</td>
<td>
1 conical roof area with 24 surfaces
(1 bldg:RoofSurface)
</td>
</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Jerkinhead Roof'''
</td>
<td width="250">
'''Gambrel Roof'''
</td>
<td width="250">
'''Arch Roof'''
</td>
<td width="250">
'''Dome Roof'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:RoofSurface-4-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-5-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-6-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-8-V1.png|220px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
4 roof surfaces
(4 bldg:RoofSurface)
</td>
<td>
4 roof surfaces
(4 bldg:RoofSurface)
</td>
<td>
1 roof surface with 12 surfaces
(1 bldg:RoofSurface)
</td>
<td>
1 roof surface with 264 surfaces
(1 bldg:RoofSurface)
</td>
</tr>
</table>

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Shed Roof I'''
</td>
<td width="250">
'''Shed Roof II'''
</td>
<td width="250">

</td>
<td width="250">

</td>

</tr>
<tr align="left" valign="top">
<td width="250">
[[image:RoofSurface-9-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-10-V1.png|250px]]
</td>
<td width="250">

</td>
<td width="250">

</td>
</tr>
<tr align="left" valign="top">
<td>
5 roof surfaces
(5 bldg:RoofSurface)
</td>
<td>
10 roof surfaces
(10 bldg:RoofSurface)
</td>
<td>

</td>
<td>

</td>
</tr>
</table>
-----
-----

==== <span id="OuterFloorSurfaces">Outer Floor Surfaces(''bldg:OuterFloorSurface'')</span> ====

===== Definition =====
'''SIG3D:''' Exterior, upper boundary surface of a building, building part or building installation which is not a roof.

The normals of an outer floor surface should generally be vertical directed upwards.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:OuterFloorSurface''
* '''LoD3:''' ''bldg:OuterFloorSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* An outer floor surface consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="400">
[[image:OuterFloorSurface-Uebersicht.png|300px]]
</td>
<td width="600">
[[image:OuterFloorSurface-Flaechen-Volumen.png|600px]]
</td>
</table>

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Roof terrace'''
</td>
<td width="250">
'''Loggia'''
</td>
<td width="250">
'''Roof terrace'''
</td>
</tr>
<tr align="left" valign="top">
<td width="300">
[[image:OuterFloorSurface-01-V1.png|300px]]
</td>
<td width="300">
[[image:OuterFloorSurface-02-V1.png|300px]]
</td>
<td width="300">
[[image:OuterFloorSurface-03-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 OuterFloorSurface
</td>
<td>
1 OuterFloorSurface
</td>
<td>
1 OuterFloorSurface
</td>
</tr>
</table>

-----
-----

==== <span id="OuterCeilingSurface">Outer Ceiling Surface(''bldg:OuterCeilingSurface'')</span> ====

===== Definition =====
'''SIG3D:''' Exterior, lower boundary surface of a building, building part or building installation against air.

The normals of an outer ceiling surface should generally be vertical directed downwards.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:OuterCeilingSurface''
* '''LoD3:''' ''bldg:OuterCeilingSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* An '''outer ceiling surface''' consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="400">
[[image:OuterFloorSurface-Uebersicht.png|300px]]
</td>
<td width="600">
[[image:OuterCeilingSurface-Flaechen-Volumen.png|600px]]
</td>
</table>

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Passage'''
</td>
<td width="250">
'''Loggia'''
</td>
<td width="250">
'''Cantilevered floor'''
</td>
</tr>
<tr align="left" valign="top">
<td width="300">
[[image:OuterCeilingSurface-02-V1.png|300px]]
</td>
<td width="300">
[[image:OuterCeilingSurface-01-V1.png|300px]]
</td>
<td width="300">
[[image:OuterCeilingSurface-03-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 OuterCeilingSurface
</td>
<td>
1 OuterCeilingSurface
</td>
<td>
1 OuterCeilingSurface
</td>
</tr>
</table>

-----
-----

==== <span id="VitualBoundarySurface">Virtual Boundary Surface (''bldg:ClosureSurface'')</span>====

===== Definition =====
'''SIG3D:''' Exterior or interior boundary surface providing virtual boundaries, typically used to seal holes in volumetric objects.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:ClosureSurface''
* '''LoD3:''' ''bldg:ClosureSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* A '''closure surface''' consists only of virtual ( imaginary ) surfaces which are '''visible from the outside''' of the building, building part or building installation.

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:opening'' <span style="color:#FF0000">not recommended</span>
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Open barn'''
</td>
<td width="250">
'''Railway platform hall'''
</td>
<td width="250">
'''Parking garage'''
</td>
</tr>
<tr align="left" valign="top">
<td width="300">
[[image:ClosureSurface-01-V1.png|300px]]
</td>
<td width="300">
[[image:ClosureSurface-03-V1.png|300px]]
</td>
<td width="300">
[[image:ClosureSurface-02-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 ClosureSurface
</td>
<td>
2 ClosureSurface
</td>
<td>
28 ClosureSurface
</td>
</tr>
</table>

-----
-----

==== <span id="Doors">Doors (''bldg:Door'')</span> ====

===== Definition =====
'''ISO 6707-1:''' Construction for closing an opening intended primarily for access or egress or both.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' not available
* '''LoD3:''' ''bldg:Door''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]

* A '''door''' consists only of surfaces which are either '''visible from the outside''' of the building, building part or building installation ( case A, B or C ) or consists of '''solids''' ( case D ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:TerrassenTuer-Detail-0.png|250px]]
</td>
<td width="250">
[[image:TerrassenTuer-Detail-0-Texture.png|250px]]
</td>
<td width="250">
[[image:TerrassenTuer-Detail-1-Flaeche.png|250px]]
</td>
<td width="250">
[[image:TerrassenTuer-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
[[image:TerrassenTuer-Schnitt-Detail-0.png|250px]]
</td>
<td>
[[image:TerrassenTuer-Schnitt-Detail-0-Texture.png|250px]]
</td>
<td>
[[image:TerrassenTuer-Schnitt-Detail-1-Flaeche.png|250px]]
</td>
<td>
[[image:TerrassenTuer-Schnitt-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Door as a simple surface)
</td>
<td>
'''Case B''' (Door as a textured surface)
</td>
<td>
'''Case C''' (Door modeled in detail with surfaces only visible from the outside)
</td>
<td>
'''Case D''' (Door as a solid)
</td>
</tr>
</table>

* In order to ensure a closed outer shell of the building, the doors should '''not''' be modeled '''in an opened state''' ( case A ) but '''in closed condition''' ( case B ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="500">
[[image:Tuer-offen-red-v1.png|500px]]
</td>
<td width="500">
[[image:Tuer-zu-red-v1.png|500px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Doors opened)
</td>
<td>
'''Case B''' (Doors closed)
</td>
</tr>
</table>

===== Attributes =====
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:address''
:points to the address of the door

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Simple Doors'''
</td>
<td width="250">
'''Simple Doors with Embrasure'''
</td>
<td width="250">
'''Doors modeled in detail'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:Beispiel-Tueren-GanzEinfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Tueren-Einfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Tueren-Komplex-Red-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
Number of Polygons (Complete Model) = 19
</td>
<td>
Number of Polygons (Complete Model) = 128
</td>
<td>
Number of Polygons (Complete Model) = 3498
</td>
</tr>
</table>

----
----

==== <span id="Windows">Windows (''bldg:Window'')</span> ====

===== Definition =====
'''SIG3D:''' Construction for closing an opening in a wall or roof, primarily intended to admit light and / or provide ventilation (cf. ISO 6707).

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' not available
* '''LoD3:''' ''bldg:Window''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]

* A '''window''' consists only of surfaces which are either '''visible from the outside''' of the building, building part or building installation ( case A, B or C ) or consists of '''solids''' ( case D ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:RechteckFenster-Detail-0.png|250px]]
</td>
<td width="250">
[[image:RechteckFenster-Detail-0-Texture.png|250px]]
</td>
<td width="250">
[[image:RechteckFenster-Detail-1-Flaeche.png|250px]]
</td>
<td width="250">
[[image:RechteckFenster-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
[[image:RechteckFenster-Schnitt-Detail-0.png|250px]]
</td>
<td>
[[image:RechteckFenster-Schnitt-Detail-0-Texture.png|250px]]
</td>
<td>
[[image:RechteckFenster-Schnitt-Detail-1-Flaeche.png|250px]]
</td>
<td>
[[image:RechteckFenster-Schnitt-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Window as a simple surface)
</td>
<td>
'''Case B''' (Window as a textured surface)
</td>
<td>
'''Case C''' (Window modeled in detail with surfaces only visible from the outside)
</td>
<td>
'''Case D''' (Window as a solid)
</td>
</tr>
</table>

* In order to ensure a closed outer shell of the building, the windows should '''not''' be modeled '''in an opened state''' ( case A ) but '''in closed condition''' ( case B ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="500">
[[image:Fenster-offen-red-v1.png|500px]]
</td>
<td width="500">
[[image:Fenster-geschlossen-red-v1.png|500px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Windows opened)
</td>
<td>
'''Case B''' (Windows closed)
</td>
</tr>
</table>

===== Attributes =====
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry

===== Examples =====

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Simple windows'''
</td>
<td width="250">
'''Simple windows with embrasure'''
</td>
<td width="250">
'''Windows modeled in detail'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:Beispiel-Fenster-GanzEinfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Fenster-Einfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Fenster-Komplex-Red-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
Number of Polygons (Complete Model) = 28
</td>
<td>
Number of Polygons (Complete Model) = 412
</td>
<td>
Number of Polygons (Complete Model) = 6269
</td>
</tr>
</table>

----
----

=== <span id ="ExtendedModeling">Extended Modeling</span> ===
The Extended Modeling covers the modeling of frequently appearing '''architectural building components''' which significantly form the building's outer appearence. These building components are modeled as '''building installations''' as a general rule.
-----
-----
==== <span id="Balconies">Balconies</span> ====

===== Definition =====
'''SIG3D:''' A '''Balcony''' is a platform attached to a building which lies above the terrain level and projects from the building structure.
It is supported by columns or console brackets, and enclosed with a balustrade [cit. en. Wikipedia]. The word's origin lies in the Italian word "balcone", which itself originates from the old-high-german word "balcho".

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====

*'''''gml:Geometry'' <span style="color:#00FF00">recommended</span>'''
** '''Threshold LOD2:'''
*** Modeling only, if the balcony's depth >= 0.5 m;
**** Plane ground-area, if the component's thickness <= 0.5 m;
**** Plane side-walls, if the component's thickness <= 0.5 m;
** '''Threshold LOD3:'''
*** Modeling only, if the balcony's depth >= 0.2 m;
**** Plane ground-Area, if the component's thickness <= 0.2 m;
**** Plane side-walls, if the component's thickness <= 0.2 m;
** '''Modeling principle'''
*** The building contains all geometry-containing border surfaces.
*** The balcony is modeled as a '''Building Installation with Geometry'''. That is without semantic differentiation.
*** The building's volume references (Xlink) to the corresponding boarder surfaces.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Balkon-Prinzip.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modeling principle of a balcony</td>
</tr>
</table>

*'''''bldg:boundedBy'' <span style="color:#FF0000">not recommended</span>'''

===== Attributes =====
;''bldg:function''
:Balcony'' (1000); see SIG 3D Codelistrecommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#FF0000">'''not recommended:'''</span> A Balcony is considered as '''one''' building component which is semantically not subdivided any further.

===== Examples =====

<table width="1200px" border="1" cellspacing="0" >

<tr align="left">
<td colspan="6">
'''Balconies'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Real Building
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td rowspan="2" width="200px" valign="top">
[[image:KHH-3-Balkone-01-red.JPG|200px]]
</td>

<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD0.png|200px]]
</td>
<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD1.png|200px]]
</td>
<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD2.png|200px]]
</td>
<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD3.png|200px]]
</td>
</tr>

<tr align="middle">
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/6/6e/KHH-3-Balkone-LOD0-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/c/ce/KHH-3-Balkone-LOD1-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/a/ac/KHH-3-Balkone-LOD2-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/d/d0/KHH-3-Balkone-LOD3-V01.gml CityGML download]
</td>
</tr>


<tr align="left">
<td colspan="6">
Above terrain level, projected from the building structure --> Balcony
</td>
</tr>
</table>

<table width="1200px" border="1" cellspacing="0">

<tr align="middle">
<td rowspan="2" width="200px" valign="top">
[[image:Eckbalkon-03-red.png|200px]]
</td>

<td width="200px" valign="top">
[[image:Eckbalkon-LOD0-01.png|200px]]
</td>
<td width="200px" valign="top">
[[image:Eckbalkon-LOD1-01.png|200px]]
</td>
<td width="200px" valign="top">
[[image:Eckbalkon-LOD2-01.png|200px]]
</td>
<td width="200px" valign="top">
[[image:Eckbalkon-LOD3-02.png|200px]]
</td>

<tr align="middle">
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/9/96/Eckbalkon-LOD0-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/4/4a/Eckbalkon-LOD1-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/7/77/Eckbalkon-LOD2-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/5/56/Eckbalkon-LOD3-V01.gml CityGML download]
</td>

</tr>
<tr align="left">
<td colspan="6">
Above terrain level, partly projected from the building structure, not bounded by 3 walls --> Balcony (no Loggia)
</td>
</tr>
</table>

-----
-----




==== Loggias ====

===== Definition =====
'''SIG3D:''' A '''Loggia''' is an enclosed on top exterior room within the building footprint, which is surrounded by '''3''' walls at full storey height. From an architectonical point of view, a '''Loggia''' (from the Italian) is a room within a building, which opens to the exterior area by means of archs or other constructional appliances. At ground floor level, Loggias create a passage between the interior area and the exterior area. At upper floor levels, Loggias are used as connection passages or as outdoor seating.

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">not recommended</span>'''

*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** '''Threshold LOD2:'''
*** Modeling only, if the Loggia's depth >= 0.5 m;
** '''Threshold LOD3:'''
*** Modeling only, if the Loggia's depth >= 0.2 m;
** '''Modeling Principle'''
*** The building contains all geometry-containing boundary surfaces

*** The Loggia (BuildingInstallation) '''references (Xlink)''' to the building's corresponding boundary surfaces. If the Loggia's floor is not part of the exterior building structure, it will be modeled as boundary surface at the building installation.
*** The building's volume references (Xlink) to the building's corresponding boundary surfaces.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Loggia-Prinzip-v2.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modeling Principle of a Loggia</td>
</tr>
</table>


===== Attributes =====
;''bldg:function''
:Loggia (1001); see SIG 3D Codelist recommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> A Loggia is considered as a building component which semantically consists of the building's boundary surfaces and possibly an exterior floor surface.

===== Examples =====

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="left">
<td colspan="6">
'''Loggien'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Real Building
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z09.png|200px]]
Interior Loggia
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z09.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_01.jpg|200px]]
[http://quality.citygmlwiki.org/images/9/9a/Loggia-01-CityGML-LOD2-V1.gml CityGML download]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z12.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_01.jpg|200px]]
[http://quality.citygmlwiki.org/images/9/9a/Loggia-01-CityGML-LOD2-V1.gml CityGML download]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z13.png|200px]]
Partly set back ground floor
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z14.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_02.jpg|200px]]
[http://quality.citygmlwiki.org/images/6/63/Loggia-02-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z13.png|200px]]
Multi-storey building with interior Loggias
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z14.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_03.jpg.png|200px]]
[http://quality.citygmlwiki.org/images/c/c2/Loggia-03-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z16.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_03.jpg.png|200px]]
[http://quality.citygmlwiki.org/images/c/c2/Loggia-03-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z17.png|200px]]
Multi-storey building, Loggias across the whole front-width and height
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z17.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_04.jpg|200px]]
[http://quality.citygmlwiki.org/images/d/d8/Loggia-04-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z17.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_04.jpg|200px]]
[http://quality.citygmlwiki.org/images/d/d8/Loggia-04-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Loggien_halbe_Breite-05-Foto-V1.png|200px]]
Loggias across half the front-width (row house)
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:|200px]]
Kamen Am Langen Kamp 25
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_05.jpg|200px]]
[http://quality.citygmlwiki.org/images/a/a9/Loggia-05-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Vorgebaute_Loggien-06-Foto-V1.jpg|200px]]
Projecting Loggias
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z14.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_Z19.png|200px]]
[http://quality.citygmlwiki.org/images/f/f6/Loggia-06-CityGML-LOD2_V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>
</table>
* In this example, the geometry is modeled within the <code>lod2Solid</code> but not within the specified <code>BoundarySurface</code> elements (opposed to the standard)!

-----
-----

==== Passages ====

===== Definition =====
SIG3D: An open '''Passage''' is a part of a building at ground level for '''vehicles''' to drive through the building. It is bounded by walls and a roof.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:BuildingInstallation''
* '''LoD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">not recommended</span>'''



*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** Threshold LOD2 / LOD3:
*** Modeling only, if the passage's depth and height >= 2 m;
** '''Modeling Principle''' (passage in a building)
*** The building contains all geometry-containing boundary surfaces.
*** The passage (BuildingInstallation) '''references (Xlink)''' to the building's corresponding boundary surfaces.
*** The building's volume references (Xlink) to the building's corresponding boarder surfaces.<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="600">[[image:Durchfahrt-Prinzip.png|600px]]</td></tr><tr align="center" valign="top"><td>Modeling principle of a passage </td></tr></table>
** '''Modeling Principle''' (Shared passage through two buildings)
*** Each building contains all geometry-containing boundary surfaces
*** The passage (BuildingInstallation) is assigned to the building which contains the greater part of the passage. The passage '''references (Xlink)''' to the building's corresponding boarder surfaces and complements the passage with bounding geometry at the BuildingInstallation.
*** The building's volume references (Xlink) to the building's corresponding boarder surfaces.<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Durchfahrt-Prinzip-Var-2.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modeling principle of a shared passage</td>
</tr>
</table>

<br />
'''Note:''' The modeling of buildings with a closed building construction is described in [[#GebäudeInGeschlossenerBauweise|Kapitel 3.7]]

===== Attributes =====
;''bldg:function''
:Passage(1002); see SIG 3D codelist recommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> A passage is considered as a building component which semantically consists of the building's boundary surfaces and possibly an exterior floor surface.

===== Examples =====
<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="left">
<td colspan="6">
'''Passages'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Actual Example
</td>

<td>
CityGML LoD0
</td>
<td>
CityGML LoD1
</td>
<td>
CityGML LoD2
</td>
<td>
CityGML LoD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Durchfahrt_Z26.png|200px]]
Passage inside of a building
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z26.png|200px]]
[http://quality.citygmlwiki.org/images/0/05/Durchfahrt-01-CityGML-LOD1-V2.gml CityGML download]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-01-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/2/20/Durchfahrt-01-CityGML-LOD2-V2.gml CityGML download]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Zwei_Gebaeude_mit_gemeinsamer_Durchfahrt-02-Foto-V1.jpg|200px]]
Two buildings with a shared passage
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z26.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-02-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/a/a5/Durchfahrt-02-CityGML-LOD2-V4.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

Two buildings with separate passages
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z27.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-03-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/f/f1/Durchfahrt-03-CityGML-LOD2-V2.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

Two offset buildings with separate passages
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z29.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-04-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/4/4c/Durchfahrt-04-CityGML-LOD2-V1.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Zwei_Gebaeude_mit_einseitiger_Durchfahrt-05-Foto-V1.jpg|200px]]
Two buildings with onesided passage
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z27.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-05-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/e/eb/Durchfahrt-05-CityGML-LOD2-V1.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Zwei_Gebaeude_mit_Verbindungstrakt-01-Foto-V1.jpg|200px]]
Two buildings with a connection section
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z31.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Durchfahrt_Z31.png|200px]]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Durchfahrt_Z53.png|200px]]
Upper floor passage
</td>

<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z53.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Durchfahrt_Z53.png|200px]]
</td>
<td width="200px" valign="bottom">
</td>
</tr>
</table>

==== Dormers / Zwerchhaus (Zwerchgiebel)====

===== Definition =====
'''SIG3D:'''
'''SIG3D:''' A '''dormer'''' is a structural element of a building that protrudes from the plane of a sloping roof surface. Dormers are used, either in original construction or as later additions, to create usable space in the roof of a building by adding headroom and usually also by enabling addition of windows [Wikipedia].

A '''dormer''' does not lie on the same plane as the building's exterior wall. The dormer (or the dormer's footprint) has a minimum offset of 0,5 m and lies inside the building's footprint.

'''SIG3D:''' The '''Zwerchhaus''' is a one or more story installation of a sloping roof surface. It consists of a gable and its own roof. The !!!Zwerchgiebel!!! follows the exterior wall's building line. That represents the difference between a !!!Zwerchhaus!!! and a gable, because a gable does not have to follow the building line. The roof of the !!!Zwerchhaus!!! is often designed as a ridge roof. The ridge follows cross to the main roof's ridge. So the rainwater pipes continue in an orthogonal way to each other.

'''Note:''' The '''zwerchhaus''' is not modeled as a part of the building installation, but as a building's boundary surface itself.

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">not recommended</span>'''

*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** Threshold LOD2:
*** Modeling only, if the dormer's height >= 2 m;
** Threshold LOD3:
***
** '''Modeling Principle'''
*** The building contains all geometry-containing boundary surfaces of the building structure. To close the building's volume, a ClosureSurface is modeled into the roof's gap.
*** The dormer (BuildingInstallation) '''contains all geometry-containing boundary surfaces''' of the dormer. To close the volume, either a ClosureSurface is modeled or it is closed by referencing to the building's corresponding ClosureSurface (Xlink to OrientableSurface).
*** The building's volume, the building structure's volume and the volume of the dormer ('''CompositeSolid''') reference (Xlink)to the corresponding boundary surfaces of the building structure and dormer.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Dachgaube-Prinzip.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modelling Principle of a dormer</td>
</tr>
</table>

===== Attributes =====
;''bldg:function''
:Dormer (1003); see SIG 3D codelisten recommendation for[http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> A dormer is considered as a building component which semantically consists of the building's boundary surfaces.

===== Examples =====
<table width="1200px" border="1" cellspacing="0" >

<tr align="left">
<td colspan="6">
'''Dormer'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Actual Example
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="top">

</td>

<td width="200px" valign="top">

</td>
<td width="200px" valign="top">

</td>
<td width="200px" valign="top">
[[image:DachgaubeClosure-01-LOD2.jpg|200px]]
[http://quality.citygmlwiki.org/images/b/b5/DachgaubeClosure-V1.gml CityGML download]
</td>
<td width="200px" valign="top">

</td>
</tr>
</table>

<table width="1200px" border="1" cellspacing="0" >

<tr align="left">
<td colspan="6">
'''Zwerchhaus (Zwerchgiebel)'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Actual Example
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="top">
[[image:Zwerchhaus-Foto-V3.jpg|200px]]
</td>

<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD0-v02.png|170px]]
[http://quality.citygmlwiki.org/images/a/a0/Zwerchgiebel-LOD0-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD1-v02.png|170px]]
[http://quality.citygmlwiki.org/images/3/32/Zwerchgiebel-LOD1-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD2-v02.png|170px]]
[http://quality.citygmlwiki.org/images/4/4b/Zwerchgiebel-LOD2-V02.gml CityGML download]
</td>
<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD3-v02.png|170px]]
[http://quality.citygmlwiki.org/images/d/d4/Zwerchgiebel-LOD3-V01.gml CityGML download]
</td>

</tr>
</table>

==== Arcades / Architrav ====

===== Definition =====
'''SIG3D:''' An arcade is a succession of arches, each counter thrusting the next, supported by columns or piers, or a covered walk enclosed by a line of such arches on one or both sides. In warmer or wet climates, exterior arcades provide shelter for pedestrians.[Wikipedia]

'''SIG3D:''' An '''architrave''' (from Italian architrave, from Greek ἀρχι, archi- and Latin trabs, bar) is the lintel or beam that rests on the capitals of the columns. It is an architectural element in Classical architecture. In the ancient world, it was also called Epistyl because it was commonly built on pillars.[Wikipedia]

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">net recommended</span>'''

*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** '''Threshold LOD2:'''
*** Threshold-values for the modelling of beams: all sides of the beam's BoundingBox are >= 0.5 m
** '''Modelling principle'''
*** The building contains all geometry-containing boundary surfaces
*** The Arcade (BuildingInstallation) '''references (Xlink)''' to the building's corresponding boundary surfaces
*** The building's volume references (Xlink) to the building's corresponding boundary surfaces

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Arkade-Prinzip.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modelling principle of an arcade</td>
</tr>
</table>

===== Attributes =====
;''bldg:function''
:Arcade (1009); see SIG 3D codelist recommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> An Arcade is considered as a building component which semantically consists of the building's boundary surfaces.

===== Examples =====

{| width="1200px" cellspacing="0" border="1" style="border:thin"
|- align="left"
| colspan="6" |
'''Arcades'''

|- valign="top" align="center"
|
Actual example


|
CityGML LOD0

|
CityGML LOD1

|
CityGML LOD2

|
CityGML LOD3

|- align="center"
| width="200px" valign="bottom" |
[[Image:Real Arkaden.png|200px]]

|

| width="200px" valign="bottom" |
[[Image:LOD1 Arkaden.png|200px]]

| width="200px" valign="bottom" |
[[Image:LOD2 Arkaden V1.png|200px]]

| width="200px" valign="bottom" |
|- align="center"
| width="200px" valign="bottom" |

| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
[[Image:LOD2 Arkaden V2.png|200px]]

| width="200px" valign="bottom" |
|}

<br>

{| width="1200px" cellspacing="0" border="1"
|- align="left"
| colspan="6" |
'''Arcade'''

|- valign="top" align="center"
|
Real Building



|
CityGML LOD0

|
CityGML LOD1

|
CityGML LOD2

|
CityGML LOD3

|- align="center"
| width="200px" valign="top" |
[[Image:Arkaden-01-Foto-V1.jpg|200px]]



| width="200px" valign="top" |
[[Image:Arkade-LOD0-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/4/43/Arkade-LoD0-Beispiel-Wiki-01-V01.gml CityGML download]

| width="200px" valign="top" |
[[Image:Arkade-LOD1-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/2/21/Arkade-LoD1-Beispiel-Wiki-01-V01.gml CityGML download]

| width="200px" valign="top" |
[[Image:Arkade-LOD2-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/e/e5/Arkade-LoD2-Beispiel-Wiki-01-V01.gml CityGML download]

| width="200px" valign="top" |
[[Image:Arkade-LOD3-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/f/fb/Arkade-LoD3-Beispiel-Wiki-01-V01.gml CityGML download]

|}

-----
-----

Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)

2014-05-07T06:43:38Z

Egbert Casper: /* Document History */

__TOC__

== Document History ==

<table border="1" cellspacing="0">
<tr align="left" valign="top">
<th width="220">
Version
</th>
<th width="220">
Date
</th>
<th width="220">
Author/s
</th>
<th width="220">
Status
</th>
<th width="220">
Remarks
</th>
</tr>

<tr align="left" valign="top">
<td>
0.1.0
</td>
<td width="220">
01.10.2010
</td>
<td>
Coors
</td>
<td>
nicht öffentlich
</td>
<td>
Erstfassung
</td>
</tr>
<tr align="left" valign="top">
<td>
0.2.0
</td>
<td width="220">
14.10.2010
</td>
<td>
Coors
</td>
<td>
nicht öffentlich
</td>
<td>
Solid ergänzt
</td>
</tr>

<tr align="left" valign="top">
<td>
0.3.0
</td>
<td width="220">
23.10.2010
</td>
<td>
Gröger
</td>
<td>
nicht öffentlich
</td>
<td>
Verschmelzung mit Paper Gröger
</td>
</tr>

<tr align="left" valign="top">
<td>
0.4.0
</td>
<td width="220">
23.11.2010
</td>
<td>
Coors
</td>
<td>
nicht öffentlich
</td>
<td>
Redaktionelle Änderungen und Ergänzungen zu Planarität von Polygonen
</td>
</tr>

<tr align="left" valign="top">
<td>
0.5.0
</td>
<td width="220">
24.11.2010
</td>
<td>
Gröger
</td>
<td>
nicht öffentlich
</td>
<td>
Einarbeitung der Änderungen, die im CityGML-Forum von K.-H. Häfele vorgeschlagen wurden
</td>
</tr>

<tr align="left" valign="top" bgcolor="green">
<td>
0.6.0
</td>
<td width="220">
15.12.2010
</td>
<td>
Gröger
</td>
<td>
öffentlich
</td>
<td>
Einarbeitung der Anregungen von G. Juen
</td>
</tr>

<tr align="left" valign="top">
<td>
0.7.0
</td>
<td width="220">
20.01.2012
</td>
<td>
Karl-Heinz Häfele
</td>
<td>
nicht öffentlich
</td>
<td>
Konvertierung in Html, Verschiebung des Kapitel Planarität von Polygonen, Neues Kapitel CompositeSolid
</td>
</tr>
<tr align="left" valign="top">
<td>
0.7.0 EN
</td>
<td width="220">
November 2013
</td>
<td>
Egbert Casper, Karl-Heinz Häfele
</td>
<td>
public
</td>
<td>
English Version </td>
</tr>

</table>

== References ==
* Cox, S., Daisey, P., Lake, R., Portele, C., Whiteside, A. (2004): OpenGIS Geography Markup Language (GML) Implementation Specification. Version: 3.1.1, OGC 03-105r1,
* Herring J. (2001): The OpenGIS Abstract Specification, Topic 1: Feature Geometry (ISO 19107 Spatial Schema), Open Geospatial Consortium, OGC Document Number 01-101. OGC.
* Gröger, G., Kolbe, T., Czerwinski, A., and Nagel, C. (2008) (Eds.): OpenGIS City Geography Markup Language (CityGML) Encoding Standard, OGC reference number OGC 08-007r1 version 1.0.0, 2008
* Gröger, G., Plümer, L. (2011): How to Achieve Consistency for 3D City Models. Geoinformatica, 15(1):137-165, DOI: 10.1007/s10707-009-0091-6.

== Preliminaries ==
* The rules refer to GML Version 3.1.
* The rules are based on the validity of the data with regard to the XML-Schema of GML 3.1.
* The rules are restricted to the elements of GML that are used in CityGML (Profile of GML, c.f. Figure 1 and Figure 2).
* If a condition applies to CityGML only (not to GML in general), it is stated explicitly.

<table border="0" cellspacing="0">
<tr align="left" valign="top">
<td>
[[image:GML-Profil-CityGML-1.png|Profil von GML]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Figure 1:''' Profile of GML that is used in CityGML (Primitives and Composites)
</td>
</tr>
</table>

<table border="0" cellspacing="0">
<tr align="left" valign="top">
<td>
[[image:GML-Profil-CityGML-2.png|Profilvon]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Figure 2:''' Profile of GML that is used in CityGML (Complexes and Aggregates)
</td>
</tr>
</table>

== <span id="Spatial-Reference-Systems">Spatial Reference Systems (SRS)</span> ==
* Each geometry element (including pos, posList and coordinates) must
** either have a srsName attribute with proper value, or
** inherit the value of the srsName attribute from
*** its parent geometries (even it its obtained recursively from the parents of the parents, etc.), or
*** the gml:Envelope (or gml:Box) which is the value of the gml:boundedBy property of the parent feature or the parent feature collection (even if it is obtained recursively).
* A local value of a srsName attribute precedes the inherited value of a srsName attribute.
* If in geometries (pos, posList) the dimension of a SRS can not be derived from the SRS without a doubt, the attribute srsDimension must contain the dimension of the SRS.

== Definitions ==

=== Geometric Tolerances ===

=== <span id="PlanarityOfPolygons">Planarity of Polygons</span> ===
„Surfaces in CityGML are represented by polygons, which define a planar geometry, i.e. the boundary and all interior points are required to be located in one single plane.” (Gröger et al., 2008). The boundary of a Polygon is defined by one or more planar Linear Rings (see gml:Polygon). From practical point of view, Linear Rings that are not exactly planar should be accepted as a valid as well.
Intuitively, a Linear Ring R would be defined as planar if there is a plane E with distance less than a given threshold  for all points Pi of R. However, this is true for Linear Rings with small bends and folds as shown in Figure 3 as well.

<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="50%">
[[image:Teil1-ABB6a.png|450px]]
</td>
<td width="50%">
[[image:Teil1-ABB6b.png|450px]]
</td>
</tr>
<tr align="left" valign="top">
<td colspan="2">
'''Figure 3:''' : Bends and folds should not appear in planar Linear Rings
</td>
</tr>
</table>

In order to avoid such situations, a slightly different definition of planarity of Linear Rings is introduced:

'''Definition 1:'''
A Linear Ring <math>R</math> is '''planar''', if it is a valid Linear Ring and the distance of all points to any plane <math>E_{ijk}</math>, that is defined by three co-linear points <math>P_i</math>, <math>P_j</math> and <math>P_k</math>, is less than a given threshold <math>\epsilon</math> :

<math>\forall E_{ijk} \forall P_a = dist (P_a,E_{ijk})\le \epsilon</math>

Für die Überprüfung der Planarität wäre es wünschenswert, eine Vorgabe für die Schranke <math>\epsilon</math> zu haben.<br> Da die Eigenschaft der Planarität invariant gegenüber Skalierungen sein sollte,<br /> sollte in den Wert von <math>\epsilon</math> die Ausdehnung bzw. Größe (Flächeninhalt, max. Punktabstand) des Linearen Ringes eingehen.<br /> Dazu sollte die Punktgenauigkeit bekannt/festgelegt sein.

== <span id="posList">[http://www.schemacentral.com/sc/niem21/e-gml32_posList.html gml:posList]</span> ==
* The number of items in the list should correlate with the product of the SRS dimension (usually in CityGML 3) and the number of positions.

== <span id="Curve"><span id="LineString">[http://www.schemacentral.com/sc/niem21/e-gml32_Curve.html gml:_Curve], [http://www.schemacentral.com/sc/niem21/e-gml32_LineString.html gml:LineString]</span></span> ==
* Only gml:LineStrings are allowed as subtypes of _Curves (rule applies to CityGML only)
* A gml:LineString has linear interpolation.
* For the child elements of a gml:LineString (control points) the following statements must hold true:
** They form a sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that belong to this curve only. "pointProperty" elements contain points that may be referenced from other geometries or that reference other points (via XLinks) which are defined in other geometries.
** Alternatively, a gml:LineString can be composed of a "posList" element, providing a compact way of representing coordinates. In that case all control points must belong to the same Curve and must be given in the same SRS. The number of points (Direct Position) must be at least two.
* Each control point in a gml:LineString occurs only once, beside the first and the last one which may both be identical.
* Line segments of a gml:LineString are defined by pairs of two subsequent control points. Those line segments must not intersect mutually and must not have any identical points. Exceptions of that rule are the pairs which consist of an endpoint of one line segment and the start point of the next line segment in the sequence.

== <span id="LinearRing">[http://www.schemacentral.com/sc/niem21/e-gml32_LinearRing.html gml:LinearRing]</span> ==

The Linear Ring is the fundamental element to describe 3D geometry in CityGML. Every single polygon of a building geometry is defined by its boundary – the Linear Ring.

A sequence is an ordered list of elements. Unlike a set, order matters, and the exact same elements can appear multiple times at different positions in the sequence. A finite sequence <math>a</math> with <math>n+1</math> elements is denoted as <math>a=(a_0,a_1,...,a_n)</math>. The empty sequence <math>a=()</math> has no elements..

A finite sequence of points <math>R=(P_0,P_1,...,P_n),n\ge3,P_i=(x_i,y_i,z_i)</math> is a Linear Ring if:

(i) the first and last point <math>P_0</math> and <math>P_n</math> represent the same point: <math>P_0 =P_n </math> '''(closeness)'''

(ii) All points of the sequence besides start and end point are different:
<math>\underset{\underset {i \ne k}{\underset{k=0...n-1}{i=0...n-1}}}{\forall} P_i\ne P_k</math>

(iii) Two edges <math>(P_i , P_{i+1})</math> and <math>(P_k , P_{k+1})</math> <math>i = 0 ... (n-1), k= 0 ... (n-1), i \not= k</math> do only intersect in one start-/ endpoint. No other intersection is allowed (no self intersection).

If all points of the sequence are co-planar, the Linear Ring is planar.

'''Examples:'''

<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="33%">
<math>R=(P_0,P_1,P_2,P_3,P_0)</math>

with

<math>P_0 =(1,1,1)</math>

<math>P_1 =(3,1,1)</math>

<math>P_2 =(3,3,1)</math>

<math>P_3 =(1,3,1)</math>
</td>
<td width="33%">
<gml:LinearRing>

<gml:pos> 1 1 1 </gml:pos>

<gml:pos> 3 1 1 </gml:pos>

<gml:pos> 3 3 1 </gml:pos>

<gml:pos> 1 3 1 </gml:pos>

<gml:pos> 1 1 1 </gml:pos>

</gml:LinearRing>
</td>
<td>
[[image:Teil1-ABB3.png]]
</td>
</tr>
<tr align="left" valign="top">
<td colspan="3">
'''Figure 4:''' Planar Linear Ring: definition, GML and graphic representation
</td>
</tr>
</table>

'''Please note:'''
The two Linear Rings <math>R_1 = (P_0,P_1,P_2,P_3,P_0)</math> and <math>R_2 = (P_0,P_3,P_2,P_1,P_0)</math> are not identical.

<table width="900px" border="0" cellspacing="0" cellpadding="5">
<tr align="left" valign="top">
<td width="33%">
[[image:Teil1-ABB4a.png]]</td>
<td width="33%">
[[image:Teil1-ABB4b.png]]</td>
<td>
[[image:Teil1-ABB4c.png]]
</td>
</tr>
<tr align="left" valign="top">
<td width="33%">
<math>R=(P_0,P_1,P_2,P_3)</math>
</td>
<td width="33%">
<math>R=(P_0,P_1,P_3,P_2,P_0)</math>
</td>
<td>
<math>R=(P_0,P_1,P_4,P_3,P_2,P_4,P_0)</math>
</td>
</tr>
<tr align="left" valign="top">
<td width="33%">
No Linear Ring: not closed (see (i) closeness)

</td>
<td width="33%">
No Linear Ring:self intersection (see (iii) self-intersection)

</td>
<td>
No Linear Ring: <math>P_4</math> appears twice in the sequence (see (ii), <math>P_4=(2,2,1)</math>)
</td>
</tr>

<tr align="left" valign="top">
<td colspan="3">
'''Figure 5:''' Examples of non-valid Linear Rings</td>
</tr>
</table>

<table width="600px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="33%">
[[image:Teil1-ABB5a.png|250px]]</td>
<td width="33%">
[[image:Teil1-ABB5b.png]]</td>

</tr>
<tr align="left" valign="top">
<td width="33%">
<math>R=(P_0,P_1,P_2,P_4,P_3,P_0)</math>
</td>
<td width="33%">
<math>R=(P_0,P_1,P_2,P_0)</math>
</td>

</tr>
<tr align="left" valign="top">
<td width="33%">
Linear Ring, but not planar <math>P_4=(2,4,0)</math></td>
<td width="33%">
No Linear Ring: all 3 points are co-linear; self-intersection (see (iii))
</td>

</tr>

<tr align="left" valign="top">
<td colspan="3">
'''Figure 6:''' Special cases: non-planar and co-linear Linear Ring Elements.</td>
</tr>
</table>

== <span id="Polygon">[http://www.schemacentral.com/sc/niem21/e-gml32_Polygon.html gml:Polygon]</span> ==
* A Polygon <math>S</math> is defined by a planar Linear Ring <math>R_s</math> (exterior ring).
* A polygon has exactly one exterior ring. In addition, a polygon can have <math>n\ge0</math> interior rings. These interior rings a planar Linear Rings as well. All interior rings and the exterior ring must be on the same plane (within the given tolerance).
* As interior rings define holes in the polygon, they have to be completely included in the area defined by the exterior ring.
<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:InnerLoops-02-2.png|500px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 7:''' Polygon mit <span style="color:#008000">korrektem interior Ring (links)</span> und <span style="color:#FF0000">nicht korrektem inneren Ring (rechts)</span> </td>
</tr>
</table>
* Interior rings must not overlap other Linear Rings or be included in another Linear Ring (except the exterior Linear Ring).
<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:InnerLoops-04-2.png|500px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 8:''' Polygon with <span style="color:#008000">two correct interior Rings (left)</span> and two interlaced, <span style="color:#FF0000">not correct interior Rings (right)</span> </td>
</tr>
</table>
* Interior rings and the exterior ring may touch each other in a finite number of points. The inner area of the polygon has to be connected.
<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:InnerLoops-05-2.png|500px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 9:''' Polygon with <span style="color:#008000">correct, interior Ring, der den außeren Ring an einem Punkt berührt (left)</span> and <span style="color:#FF0000">not correct interior Ring, der den äußeren Ring an zwei Punkten berührt und damit dass Polygon spaltet (rechts)</span> </td>
</tr>
</table>
* • The order of points of the exterior ring defines the orientation of the polygon. The non co-linear points <math>P_i</math>, <math>P_j</math> und <math>P_k</math>define the plane <math>E(P_i,P_j,P_k)</math>. The normal vector <math>\vec n</math> is given by the cross product of the two vectors <math>\vec{P_iP_j}</math> and <math>\vec{P_jP_k}</math>:

<math>\vec n = \frac {\vec{P_iP_j}\times\vec{P_jP_k}}{\| {\vec{P_iP_j}\times\vec{P_jP_k}}\|}</math>

'''Please note:''' that due to the tolerance of planar Linear Rings, the normal vector can be ambiguous.

'''Remark:'''
The two Linear Rings <math>R_1=(P_0,P_1,P_2,P_3,P_0)</math> and <math>R_2=(P_0,P_3,P_2,P_1,P_0)</math> define polygons with the same geometric extend but different orientation.

<table width="900px" border="0" cellspacing="0">
<tr align="left" valign="top">
<td width="100%">
[[image:Teil1-ABB7.png|300px]]
</td>

</tr>
<tr align="left" valign="top">
<td colspan="1">
'''Figure 10:''' Polygon with normal vector n</td>
</tr>
</table>

== <span id="OrientableSurface">[http://www.schemacentral.com/sc/niem21/e-gml32_OrientableSurface.html gml:OrientableSurface]</span> ==
* If the value of the attribute “orientation” of an OrientableSurface is "+", the orientation of the OrientableSurface is identical to the one of the baseSurface. If the value of “orientation is " ", the normal of the OrientableSurface has a direction which is opposite to the normal of the baseSurface. The default value of “orientation” is "+".
* Either the element “baseSurface” references the base surface via a XLink attribute or the element “baseSurface” contains the base surface as child element. The base surface has positive orientation.

== <span id="MultiSurface">[http://www.schemacentral.com/sc/niem21/e-gml32_MultiSurface.html gml:MultiSurface]</span> ==
A MultiSurface is an unstructured set <math>M=\lbrace S_1,S_2,...S_n\rbrace</math> of polygons. No further constraints are defined for a MultiSurface element. It is not necessary that <math>M</math> is a connected surface. Orientation of the polygons is arbitrary. By a MultiSurface any existing polygonal boundary representation of a rigid body can be described. Unfortunately, also objects that do not exist in real space can be modeled.

Due to the missing constraints it is recommended that MultiSurface elements should only be used to model non-volumetric parts of the building model as shown in Figure 11. Volumetric parts should be modeled as solids (see gml:Solid)

<table width="700px" border="0" cellspacing="0">

<tr align="left" valign="top">
<td width="50%">
[[image:MultiSurface-01a.png|300px]]
</td>
<td width="50%">
[[image:MultiSurface-01a.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td width="50%">
[[image:MultiSurface-Explode-01a.png|300px]]
</td>
<td width="50%">
[[image:MultiSurface-Explode-01b.png|300px]]
</td>
</tr>

<tr align="left" valign="top">
<td colspan="2">
'''Figure 11:''' Modeling overlapping roof parts ('''above:''' complete models, polygons outlined; '''below:''' roof polygons exploded)

'''Please note:''' the left model in Figure 11 is created with a MultiSurface element containing 7 polygons. However, the polygons do not represent a valid boundary of a rigid body. Calculating a volume is not possible. The right model is the same building geometry but modeled with 1 Solid element (7 polygons) and 1 MultiSurface element (2 polygons F6 and F8) as recommended (see CityGML Standard v1.0,p.61)

</td>
</tr>
</table>

== <span id="CompositeSurface"> [http://www.schemacentral.com/sc/niem21/e-gml32_CompositeSurface.html gml:CompositeSurface]</span>==

Eine CompositeSurface ist eine Menge <math>C=\lbrace S_1,S_2,...,S_n \rbrace</math> von Polygonen, für die
folgendes gilt:

# Die Schnittmenge zweier Polygone <math>S_k</math> und <math>S_l</math> aus <math>C</math> ist entweder leer oder besteht nur aus Punkten und/oder Kanten, die auch in den beiden linearen Ringen vorkommen. Bezeichne <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math> den planaren linearen Ring, der das Polygon <math>S</math> definiert. Dann gilt:<br><math>S_i \cap S_k= \begin{cases}\emptyset\\ \lbrace Q_0,Q_1,...,Q_m\rbrace,Q_j=P_k^i\\ \lbrace e_0,e_1,...,e_m\rbrace,e_j=\overline{P_i^kP_{i+1}^k} \end{cases}</math>
# Jede Kante <math>e_k=\overline{P_i^kP_{i+1}^k}</math> eines linearen Rings <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math> , der ein Polygon <math>S_k \in C</math> definiert, wird höchstens einmal als Kante <math>e_l=\overline{P_j^lP_{j+1}^l}</math> in einem linearen Ring <math>R_l=(P_0^l,P_1^l,...,P_m^l)</math> genutzt, der ein anderes Polygon <math>S_l \in C</math> definiert.<br>Es gilt <math>P_i^k=P_{j+1}^l</math> und <math>P_{i+1}=P_j^l</math>.
# Die Polygone aus <math>C</math> sind so orientiert, dass die Flächennormale benachbarte Polygone in dieselbe Richtung zeigen.
# Die Vereinigung aller Polygone aus <math>C</math> ohne die Kanten oder Punkte, in denen sich die Polygone berühren, ist isomorph zu einem Polygon.

Aus (1) und (2) ergibt sich, dass die Oberfläche, die durch <math>C</math> beschrieben wird, keine sich gegenseitig überlappenden oder durchdringenden Polygone enthalten darf (Polygone berühren sich höchstens in Punkten oder Kanten).

== <span id="Solid"> [http://www.schemacentral.com/sc/niem21/e-gml32_Solid.html gml:Solid]</span>==

A solid geometry represents a rigid body. The surface of the solid is defined by a set of polygons with the following properties.
The set <math>C=\lbrace S_1,S_2,...,S_n \rbrace</math> of polygons bounds a solid if:

# The intersection of two polygons <math>S_k</math> and <math>S_l</math> of <math>C</math> is either empty or contains only points <math>P</math> and edges <math>e</math> that are part of both Linear Rings. The polygon <math>S</math> is defined by the Linear Ring <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math>. The intersection of <math>S_k</math> and <math>S_l</math> equals: <br><math>S_i \cap S_k= \begin{cases}\emptyset\\ \lbrace Q_0,Q_1,...,Q_m\rbrace,Q_j=P_k^i\\ \lbrace e_0,e_1,...,e_m\rbrace,e_j=\overline{P_i^kP_{i+1}^k} \end{cases}</math>
# Every Edge <math>e_k=\overline{P_i^kP_{i+1}^k}</math> of a Linear Ring <math>R_k=(P_0^k,P_1^k,...,P_n^k)</math> , defining a polygon <math>S_k \in C</math>, is used exactly once as an edge <math>e_l=\overline{P_j^lP_{j+1}^l}</math> in a Linear Ring <math>R_l=(P_0^l,P_1^l,...,P_m^l)</math>, defining another polygon <math>S_l \in C</math> with <math>P_i^k=P_{j+1}^l</math> and <math>P_{i+1}=P_j^l</math>.
# All polygons in <math>C</math> are oriented such that the normal vector of each polygon points to the outside of the solid.
# All polygons in <math>C</math> are connected, that is the dual graph of <math>C</math> has a path containing all nodes. The dual graph G<sub>C</sub> =(V<sub>C</sub>, E<sub>C</sub>) of <math>C</math> consists of a set V<sub>C</sub> of nodes and a set E<sub>C</sub> of edges. Every node v of V<sub>C</sub> represents exactly one polygon of <math>C</math>. An edge shared by two polygons <math>S_k</math> and <math>S_l</math> of <math>C</math> is represented by an edge <math>e=(v_{s_k},v_{s_l})</math> in E<sub>C</sub>.
# For every point <math>P</math> of a Linear Ring of a polygon of <math>C </math> applies: The graph <math>G_P =(V_P, E_P)</math>, that is only build by polygons and edges that touch<math>P</math> is connected. Each node <math>v</math> of <math>V_P</math> represents a polygon which Linear Ring contains <math>P</math>. Two nodes are connected by an edge <math>e</math> of <math>E_P</math> if the two polygons represented by the nodes have a common edge that touches <math>P</math>.

It follows from (i) and (ii) that the surface defined by <math>C</math> has no holes. Together with conditions (4) and (5) it follows that the inner of the solid defined by <math>C</math> is connected
<math>S</math> is denoted as closed [http://www.schemacentral.com/sc/niem21/e-gml32_CompositeSurface.html '''CompositeSurface'''].

'''Beispiele:'''

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:Solid-Fall-01.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-02.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-03.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-04.png|200px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="top">
Korrekt: 6 Flächen, geschlossen, Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Korrekt: 11 Flächen, geschlossen, Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Korrekt: 10 Flächen, geschlossen, Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Korrekt: 30 Flächen, geschlossen, Flächenorientierung korrekt
</td>
</tr>
</table>

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:Solid-Fall-05.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-06.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-07.png|200px]]
</td>
<td width="300px">
[[image:Solid-Fall-08.png|200px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="top">
Nicht Korrekt: 5 Flächen, nicht geschlossen, Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Nicht Korrekt: 6 Flächen, geschlossen, Flächenorientierung nicht korrekt
</td>
<td width="300px" valign="top">
Nicht Korrekt: 12 Flächen, nicht geschlossen (zwei Außenhüllen), Flächenorientierung korrekt
</td>
<td width="300px" valign="top">
Nicht Korrekt: 12 Flächen, nicht geschlossen (innere und äußere Hülle), Flächenorientierung korrekt
</td>
</tr>
</table>

== <span id="CompositeSolid">[http://www.schemacentral.com/sc/niem21/e-gml32_CompositeSolid.html gml:CompositeSolid]</span>==
Ein CompositeSolid wird durch eine nichtleere Menge <math>C = \{S_1,..., S_n\}</math> von '''[[#Solid|Solids]]''' (vgl. 12.) beschrieben, für die gilt:

# Der Schnitt der Inneren zweier Solids <math>S_i</math>, <math>S_j</math>, 1 ≤ i ≤ n, 1 ≤ j ≤ n, i ≠ j, ist leer, d.h. entweder sind beide Solids <math>S_i</math>, <math>S_j</math> disjunkt oder beide berühren sich nur in Flächen, Linien oder Punkten
# Sei <math>C'</math> die Vereinigung aller Solids aus <math>C</math>. Dann ist die Begrenzung von <math>C'</math> (die Oberfläche von <math>C'</math> ohne die Flächen oder Punkte, in denen sich die Solids berühren) die Begrenzung eines Solid.

In CityGML werden bei CompositeSolids ebenso wie bei Solids innere Einschlüsse (Hohlräume) nicht betrachtet.

'''Examples:'''

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:CompositeSolid-01-Fall01.png|300px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall02.png|220px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall03.png|240px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall04.png|260px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="bottom">
correct; surface contact
</td>
<td width="300px" valign="bottom">
correct; surface contact
</td>
<td width="300px" valign="bottom">
correct; surface contact
</td>
<td width="300px" valign="bottom">
correct; surface contact
</td>

</tr>

</table>

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:CompositeSolid-01-Fall05.png|260px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall06.png|260px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall07.png|280px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall08.png|180px]]
</td>

</tr>

<tr align="middle">

<td width="300px" valign="bottom">
not correct; line contact
</td>
<td width="300px" valign="bottom">
not correct; point contact
</td>
<td width="300px" valign="bottom">
not correct; no contact at all
</td>
<td width="300px" valign="bottom">
not correct; intersection
</td>

</tr>

</table>

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="middle" valign="top">
<td width="300px">
[[image:CompositeSolid-01-Fall14.png|220px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall14a.png|220px]]
</td>
<td width="300px">
[[image:CompositeSolid-01-Fall14b.png|220px]]
</td>

</tr>

<tr align="middle">
<td width="300px" valign="bottom">
not correct; 26 boxes with surface contact
</td>
<td width="300px" valign="bottom">
but with internal hollow space
</td>
<td width="300px" valign="bottom">
not correct; interior boundaries
</td>

</tr>

</table>

== <span id="Triangle">[http://www.schemacentral.com/sc/niem21/e-gml32_Triangle.html gml:Triangle]</span> ==
* A Triangle is a special case of a polygon that is bounded by one outer Linear Ring with four points.
* There are no interior rings (no element "interior").

== <span id="TriangulatedSurface">[http://www.schemacentral.com/sc/niem21/e-gml32_TriangulatedSurface.html gml:TriangulatedSurface]</span> ==
A triangulated surface is a [[#CompositeSurface|CompositeSurface]] that consists of triangles only, but is not closed (it may have boundaries). There is no restriction on how the triangulation is derived.

== <span id="TIN">[http://www.schemacentral.com/sc/niem21/e-gml32_Tin.html gml:Tin] </span>==
In contrast to a gml:TriangulatedSurface, the triangles of a gml:TIN are not represented explicitly, but by its three vertices (called control points). In addition, breaklines, stop lines and the maximal length of a side of a triangle can be represented in a gml:TIN.

# A TIN is a triangulated surface that is the result of the application of a Delaunay Algorithm or of a similar algorithm (extended by breaklines, stop lines and the maximal length of a side of a triangle). The surface satisfies the Delaunay criterion:
## For each triangle in the network, the circle passing through its vertices does not contain, in its interior, the vertex of any other triangle.
# Stoplines are lines where the local continuity or regularity of the surface is questionable. In the area of these pathologies, triangles intersecting a stopline shall be removed from the TIN surface, leaving holes in the surface. If triangles incident to the boundary of the surfaces are removed, the boundary of the surfaces changes.
# Breaklines are lines that are critical for the shape of the surface, representing local ridges, or depressions (such as drainage lines) in the surface. As such their constituent segments must be included in the TIN even if doing so violates the Delaunay criterion.
# Areas of the surface where the data is not sufficiently dense to assure reasonable calculations shall be removed by adding a retention criterion for triangles based on the length of their sides. For any triangle sides exceeding maximum length, the adjacent triangles to that triangle side shall be removed from the surface. # The number of control points is at least three.
# The surface is not affected by the order in which the control points are given. Application schemas may add information based on the ordering of the control points to facilitate the reconstruction of the TIN from the control points.

Main Page

2014-05-03T06:23:45Z

Egbert Casper: /* SIG 3D Quality Working Group */

= SIG 3D Quality Working Group =

'''Welcome at the Wiki of the SIG3D Quality Working Group'''

Consult the [http://www.sig3d.org/index.php?catid=2&language=en SIG3D web site] for general information about the SIG3D.

<br>

[[Image:20130901_SIG3D_QualityConcept.svg|center|700px|link=Main Page]]

{| cellspacing="6" border="0" align="center"
|- valign="top" align="left"
| width="100" |
[[Image:20130901_SIG3D_QualityConcept_1_3.svg|100px|link=General]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_2_3.svg|100px|link=Modeling]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_3_2.svg|100px|link=Profiles]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_4_2.svg|100px|link=Testing]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_5_1.svg|100px|link=Certification]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_6_1.svg|100px|link=Standard Specifications]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_7_1.svg|100px|link=Continuation]]

|}

<br>

{| width="100%" cellspacing="6" border="0"
|- valign="top" align="left"
| width="50%" | <div style="margin: 10px; border: 2px solid #dfdfdf; background-color:#f8f8ff;">{{Willkommen AG Qualitaet}}</div>
|}

{| width="100%" cellspacing="6" border="0"
|- valign="top" align="left"
| width="80%" | <div style="margin: 10px; border: 2px solid #dfdfdf; background-color:#f8f8ff;">{{Kontakt}}</div>
|}

{| width="100%" cellspacing="6" border="0"
|- valign="top" align="left"
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|}

Main Page

2014-05-03T06:23:19Z

Egbert Casper: /* SIG 3D Quality Working Group */

= SIG 3D Quality Working Group =

'''Welcome at the Wiki of the SIG3D Quality Working Group'''

Consult the [http://www.sig3d.org/index.php?catid=2&language=en SIG3D web site] for further information about the SIG3D in general.

<br>

[[Image:20130901_SIG3D_QualityConcept.svg|center|700px|link=Main Page]]

{| cellspacing="6" border="0" align="center"
|- valign="top" align="left"
| width="100" |
[[Image:20130901_SIG3D_QualityConcept_1_3.svg|100px|link=General]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_2_3.svg|100px|link=Modeling]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_3_2.svg|100px|link=Profiles]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_4_2.svg|100px|link=Testing]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_5_1.svg|100px|link=Certification]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_6_1.svg|100px|link=Standard Specifications]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_7_1.svg|100px|link=Continuation]]

|}

<br>

{| width="100%" cellspacing="6" border="0"
|- valign="top" align="left"
| width="50%" | <div style="margin: 10px; border: 2px solid #dfdfdf; background-color:#f8f8ff;">{{Willkommen AG Qualitaet}}</div>
|}

{| width="100%" cellspacing="6" border="0"
|- valign="top" align="left"
| width="80%" | <div style="margin: 10px; border: 2px solid #dfdfdf; background-color:#f8f8ff;">{{Kontakt}}</div>
|}

{| width="100%" cellspacing="6" border="0"
|- valign="top" align="left"
| width="80%" | <div style="margin: 10px; border: 2px solid #dfdfdf; background-color:#f8f8ff;">{{Copyright}}</div>
|}

Main Page

2014-05-03T06:21:30Z

Egbert Casper: /* SIG 3D Quality Working Group */

= SIG 3D Quality Working Group =

[[Image:20130901_SIG3D_QualityConcept.svg|center|700px|link=Main Page]]

{| cellspacing="6" border="0" align="center"
|- valign="top" align="left"
| width="100" |
[[Image:20130901_SIG3D_QualityConcept_1_3.svg|100px|link=General]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_2_3.svg|100px|link=Modeling]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_3_2.svg|100px|link=Profiles]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_4_2.svg|100px|link=Testing]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_5_1.svg|100px|link=Certification]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_6_1.svg|100px|link=Standard Specifications]]

| width="100" |
[[Image:20130901_SIG3D_QualityConcept_7_1.svg|100px|link=Continuation]]

|}

<br>

'''Welcome at the Wiki of the SIG3D Quality Working Group'''

Consult the [http://www.sig3d.org/index.php?catid=2&language=en SIG3D web site] for further information about the SIG3D.

{| width="100%" cellspacing="6" border="0"
|- valign="top" align="left"
| width="50%" | <div style="margin: 10px; border: 2px solid #dfdfdf; background-color:#f8f8ff;">{{Willkommen AG Qualitaet}}</div>
|}

{| width="100%" cellspacing="6" border="0"
|- valign="top" align="left"
| width="80%" | <div style="margin: 10px; border: 2px solid #dfdfdf; background-color:#f8f8ff;">{{Kontakt}}</div>
|}

{| width="100%" cellspacing="6" border="0"
|- valign="top" align="left"
| width="80%" | <div style="margin: 10px; border: 2px solid #dfdfdf; background-color:#f8f8ff;">{{Copyright}}</div>
|}

2013-12-17T13:08:00Z

Egbert Casper: /* B */

__NOTOC__
{{compactTOC2}}

==A==

==B==
;<span id="Building">Building</span>
:'''ISO 6707-1(2004):''' Provision of shelter for its occupants or contents as one of its main purposes; usually partially or totally enclosed and designed to stand permanently in one place.

;<span id="Balcony">Balcony</span>
:'''ISO 6707-1(2004):''' Upper accessible platform within a storey, not fully enclosed by wall(s).
::An '''external balcony''' is an accessible platform that projects from the external face of a building.
::An '''internal balcony''' or '''recessed balcony''' (US) is an accessible platform recessed from the external face of a building.

==C==
;<span id="Ceiling">Ceiling</span>
:[http://en.wikipedia.org/wiki/Ceiling '''Wikipedia:'''] A ceiling is an overhead interior surface that covers the upper limit of a room. It is not generally considered a structural element, but a finished surface concealing the underside of the floor or roof structure above.

;<span id="CCRS">Compound Coordinate Referencesystem (CCRS)</span>
:'''ISO 19111:''' Coordinate reference system using two other independent coordinate reference systems to describe a position.
:The horizontal and vertical components of a description of position in three dimensions may sometimes come from different coordinate reference systems rather than through a single three-dimensional coordinate reference system. This is always the case for positions where vertical coordinates are related to mean sea level. This shall be handled through a compound coordinate reference system which identifies the two coordinate reference system utilized.
:Notification by using a "*" combining the two coordinate reference systems, e.g. DE_DHDN_3GK2_RDN*DE_DHHN92_NH

==D==
;<span id="Door">Door</span>
:[http://en.wikipedia.org/wiki/Door '''Wikipedia:'''] A door is an opening or closing structure used to block off an entrance, typically consisting of an interior side that faces the inside of a space and an exterior side that faces the outside of that space. While in some cases the interior side of a door may match its exterior side, in other cases there are sharp contrasts between the two sides, such as in the case of the vehicle door. In addition, doors typically consist of a panel that swings on hinges or that slides or spins inside of a space.
:'''ISO 6707-1(2004):''' Construction for closing an opening intended primarily for access or egress or both.

==E==

==F==
;<span id="Floor">Floor</span>
:[http://en.wikipedia.org/wiki/Floor'''Wikipedia:'''] A floor is the walking surface of a room or vehicle. Floors vary from simple dirt in a cave to many-layered surfaces using modern technology. Floors may be stone, wood, bamboo, metal, or any other material that can hold a person's weight.
:The levels of a building are often referred to as floors although a more proper term is storey.

==G==

==H==

==I==

==J==

==K==

==L==

==M==

==N==

==O==
;Opening
: '''CityGML:''' Abstract class for door and window

==P==

==Q==

==R==
;<span id="Roof">Roof</span>
:[http://en.wikipedia.org/wiki/Roof'''Wikipedia:'''] A roof is the covering on the uppermost part of a building. A roof protects the building and its contents from the effects of weather and the invasion of animals. Structures that require roofs range from a letter box to a cathedral or stadium, dwellings being the most numerous.

==S==
;<span id="Storey">Storey</span>
:'''ISO 6707-1(2004):''' Space between two consecutive floors or between a floor and a roof.

==T==

==U==
==V==

==W==
;<span id="Wall">Wall</span>
:[http://en.wikipedia.org/wiki/Wall'''Wikipedia:'''] A wall is a vertical structure, usually solid, that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into sections, or protects or delineates a space in the open air. There are three principal types of structural walls: building walls, exterior boundary walls, and retaining walls.
:'''ISO 6707-1(2004)''' Vertical construction that bounds or subdivides a space and usually fulfils a loadbearing or retaining function.
;<span id="Window">Window</span>
:[http://en.wikipedia.org/wiki/Window'''Wikipedia:'''] A window is a transparent or translucent opening in a wall, door or vehicle that allows the passage of light and, if not closed or sealed, air and sound. Windows are usually glazed or covered in some other transparent or translucent material. Windows are held in place by frames. Many glazed windows may be opened, to allow ventilation, or closed, to exclude inclement weather.
:'''ISO 6707-1(2004)''' Construction for closing a vertical or near-vertical opening in a wall or pitched roof, which will admit light and may provide ventilation.

==X==

==Y==

==Z==

{{compactTOC2}}

Definitionen

2013-12-17T13:04:06Z

Egbert Casper: /* S */

__NOTOC__
{{compactTOC2}}

==A==

==B==
;<span id="Building">Building</span>
:'''ISO 6707-1(2004):'''Provision of shelter for its occupants or contents as one of its main purposes; usually partially or totally enclosed and designed to stand permanently in one place.

==C==
;<span id="Ceiling">Ceiling</span>
:[http://en.wikipedia.org/wiki/Ceiling '''Wikipedia:'''] A ceiling is an overhead interior surface that covers the upper limit of a room. It is not generally considered a structural element, but a finished surface concealing the underside of the floor or roof structure above.

;<span id="CCRS">Compound Coordinate Referencesystem (CCRS)</span>
:'''ISO 19111:''' Coordinate reference system using two other independent coordinate reference systems to describe a position.
:The horizontal and vertical components of a description of position in three dimensions may sometimes come from different coordinate reference systems rather than through a single three-dimensional coordinate reference system. This is always the case for positions where vertical coordinates are related to mean sea level. This shall be handled through a compound coordinate reference system which identifies the two coordinate reference system utilized.
:Notification by using a "*" combining the two coordinate reference systems, e.g. DE_DHDN_3GK2_RDN*DE_DHHN92_NH

==D==
;<span id="Door">Door</span>
:[http://en.wikipedia.org/wiki/Door '''Wikipedia:'''] A door is an opening or closing structure used to block off an entrance, typically consisting of an interior side that faces the inside of a space and an exterior side that faces the outside of that space. While in some cases the interior side of a door may match its exterior side, in other cases there are sharp contrasts between the two sides, such as in the case of the vehicle door. In addition, doors typically consist of a panel that swings on hinges or that slides or spins inside of a space.
:'''ISO 6707-1(2004):''' Construction for closing an opening intended primarily for access or egress or both.

==E==

==F==
;<span id="Floor">Floor</span>
:[http://en.wikipedia.org/wiki/Floor'''Wikipedia:'''] A floor is the walking surface of a room or vehicle. Floors vary from simple dirt in a cave to many-layered surfaces using modern technology. Floors may be stone, wood, bamboo, metal, or any other material that can hold a person's weight.
:The levels of a building are often referred to as floors although a more proper term is storey.

==G==

==H==

==I==

==J==

==K==

==L==

==M==

==N==

==O==
;Opening
: '''CityGML:''' Abstract class for door and window

==P==

==Q==

==R==
;<span id="Roof">Roof</span>
:[http://en.wikipedia.org/wiki/Roof'''Wikipedia:'''] A roof is the covering on the uppermost part of a building. A roof protects the building and its contents from the effects of weather and the invasion of animals. Structures that require roofs range from a letter box to a cathedral or stadium, dwellings being the most numerous.

==S==
;<span id="Storey">Storey</span>
:'''ISO 6707-1(2004):''' Space between two consecutive floors or between a floor and a roof.

==T==

==U==
==V==

==W==
;<span id="Wall">Wall</span>
:[http://en.wikipedia.org/wiki/Wall'''Wikipedia:'''] A wall is a vertical structure, usually solid, that defines and sometimes protects an area. Most commonly, a wall delineates a building and supports its superstructure, separates space in buildings into sections, or protects or delineates a space in the open air. There are three principal types of structural walls: building walls, exterior boundary walls, and retaining walls.
:'''ISO 6707-1(2004)''' Vertical construction that bounds or subdivides a space and usually fulfils a loadbearing or retaining function.
;<span id="Window">Window</span>
:[http://en.wikipedia.org/wiki/Window'''Wikipedia:'''] A window is a transparent or translucent opening in a wall, door or vehicle that allows the passage of light and, if not closed or sealed, air and sound. Windows are usually glazed or covered in some other transparent or translucent material. Windows are held in place by frames. Many glazed windows may be opened, to allow ventilation, or closed, to exclude inclement weather.
:'''ISO 6707-1(2004)''' Construction for closing a vertical or near-vertical opening in a wall or pitched roof, which will admit light and may provide ventilation.

==X==

==Y==

==Z==

{{compactTOC2}}

2013-12-17T11:15:57Z

Egbert Casper: /* Attributes */

{{TOC limit|4}}
== Document History ==

<table border="1" cellspacing="0">
<tr align="left" valign="top">
<th width="220">
Version
</th>
<th width="220">
Datum
</th>
<th width="220">
Autor/en
</th>
<th width="220">
Status
</th>
<th width="220">
Bemerkungen
</th>
</tr>
<tr align="left" valign="top">
<td>
0.8.0
</td>
<td width="220">
Januar 2012
</td>
<td>
</td>
<td bgcolor="#ff7777">
nicht öffentlich
</td>
<td>
Erste Versuche
</td>
</tr>
<tr align="left" valign="top">
<td>
0.9.0
</td>
<td width="220">
April 2012
</td>
<td>
</td>
<td bgcolor="#ff7777">
nicht öffentlich
</td>
<td>
Fertigstellung von Kapitel 1-4.1; 4.2 wird später bearbeitet
</td>
</tr>
<tr align="left" valign="top">
<td>
1.0.0
</td>
<td width="220">
Mai 2012
</td>
<td>
SIG 3D / AG Qualität
</td>
<td bgcolor="#73ff73">
öffentlich
</td>
<td>
Erste öffentliche Version von Kapitel 1-4.1;
</td>
</tr>
<tr align="left" valign="top">
<td>
1.1.0
</td>
<td width="220">
Januar/Februar 2013
</td>
<td>
SIG 3D / AG Qualität
</td>
<td bgcolor="#ff7777">
nicht öffentlich
</td>

<td>
Vorbereitung Version 2.0.0 mit Erweiterter Modellierung;
</td>
</tr>
<tr align="left" valign="top">
<td>
2.0.0
</td>
<td width="220">
März 2013
</td>
<td>
SIG 3D / AG Qualität
(c) 2013 Copyright Special Interest Group 3D (SIG3D) of the Spatial Data Infrastructure Germany (GDI-DE) http://www.sig3d.org
</td>
<td bgcolor="#73ff73">
öffentlich
</td>

<td>
Erste öffentliche Version mit Erweiterter Modellierung;
</td>
</tr>
<tr align="left" valign="top">
<td>
2.0.0 EN
</td>
<td width="220">
November 2013
</td>
<td>
SIG 3D / Quality Working Group
(c) 2013 Copyright Special Interest Group 3D (SIG3D) of the Spatial Data Infrastructure Germany (GDI-DE) http://www.sig3d.org /EC, KHH
</td>
<td bgcolor="#73ff73">
public </td>

<td>
First English version;
</td>
</tr>

</table>
-----
-----

== Introduction ==

=== Scope ===
* The modeling recommendations are usually independent from the recording method that means that this document is '''not''' a recording manual.
* This document describes the modeling of 3D objects on the basis of '''existing information'''. In case of lacking information, in particular in case of missing height information, objects must '''explicitly not''' be modeled. For example, if all relevant information on balconies is available, this document provides recommendations for a standardized modeling. Otherwise balconies must not be modeled.
* Recommendations are related to the Open Geospatial Consortium (OGC) standard '''CityGML version 1.0 and 2.0'''.
* This document refers to '''national (German) and European standards''' (AdV, INSPIRE) and can only be partially generalized.
* This document is restricted to the '''outer shell''' of buildings, i.e. building modeling up to LoD3
-----
-----

=== Target Group===
* Modeler
* Data holder
* Developer
-----
-----

=== Prior Knowledge Required ===
* GML: Geography Markup Language
* CityGML: Application schema for GML for the representation, storage, and exchange of virtual 3D city and landscape models
* [[ALKIS]]: Official German Land Registry Information System
-----
-----

=== Further References ===
* [https://portal.opengeospatial.org/modules/admin/license_agreement.php?suppressHeaders=0&access_license_id=3&target=http://portal.opengeospatial.org/files/%3fartifact_id=28802 CityGML 1.0 Specification]

* [https://portal.opengeospatial.org/modules/admin/license_agreement.php?suppressHeaders=0&access_license_id=3&target=http://portal.opengeospatial.org/files/%3fartifact_id=47842 CityGML 2.0 Specification]

* [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)]]

* [http://www.adv-online.de/icc/extdeu/binarywriterservlet?imgUid=42b23fd2-1153-911a-3b21-718a438ad1b2&uBasVariant=11111111-1111-1111-1111-111111111111&isDownload=true GeoInfoDok V 6.0 - Modeling of the geoinformation of the official surveying and mapping of Germany (Main Document, in German only)]

* [http://www.adv-online.de/AAA-Modell/Dokumente-der-GeoInfoDok/binarywriterservlet?imgUid=c9e63fd2-1153-911a-3b21-718a438ad1b2&uBasVariant=11111111-1111-1111-1111-111111111111&isDownload=true ALKIS feature catalogue with building information ( in German only)]
-----
-----

=== Document Conventions ===
* '''Features''' are written in ''italic characters'' with the corresponding name space in ''' ''bold characters'' '''.
* '''Examples''' are written in <tt>fixed width</tt>.
* '''Online references''' to other internal or external pages and documents are written in <span style="color:blue;">blue</span>.
* A statement which is not valid for all '''Levels of Detail''' (LoD) is noted as (LoD[1234][+]), e.g. a notation with (LoD1) is only valid for LoD1, a notation (LoD2+) is valid for all LoDs from LoD2 and above.
-----
-----

== Definitions und Determinations ==

=== Level of Detail (Building, BuildingPart)===

'''Definitions of SIG 3D:'''
* LoD0
** For every building or building part the footprint or roof outline is representad by a horizontal polygon with a well defined absolute and constant height.
* LoD1
** For every building or building part the generalized outer shell is represented by exactly one prismatic extrusion solid. Ground, floor and roof surfaces must be horizontal, lateral boundary surfaces must be vertical.
* LoD2
** For every building or building part the geometrically simplified outer shell is represented by horizontal resp. vertical outer surfaces and simplified roof shapes. All kind of surfaces ( e.g. ground surfaces, wall surfaces, roof surfaces, outer ceiling surfaces, outer floor surfaces, virtual closure surfaces ) and additional building elements ( e.g. building installations like balkonies, dormers and chimneys ) may be represented as semantic objects.
* LoD3
** For every building or building part the geometrically detailed outer shell is represented by detailed outer surfaces and detailed roof shapes. All kind of surfaces ( e.g. ground surfaces, wall surfaces, roof surfaces, outer ceiling surfaces, outer floor surfaces, virtual closure surfaces ) and additional building elements ( e.g. building installations like balkonies, dormers and chimneys ) may be more detailly represented as semantic objects. In respect to LoD2 doors and windows can be modeled as planar thematic objects.
* LoD4
** For every building or building part the geometrically detailed outer shell and interior is represented by detailed outer and inner surfaces and detailed roof shapes. All kind of surfaces ( e.g. ground surfaces, inner and outer wall surfaces, inner and outer roof surfaces, outer ceiling surfaces, outer floor surfaces, virtual closure surfaces ) and additional movable and non movable building elements ( e.g. building installations like balkonies, dormers, chimneys, interior and furniture ) may be more detailly represented as semantic objects.
-----

=== Reference Coordinate System ===
CityGML 2.0 strongly recommends the specification of a reference coordinate system. For a meaningful use of data a valid reference coordinate system is imperative, therefore a valid reference coordinate system must be defined for each instance file:

* A reference coordinate system must be defined as '''three dimensional''' (usually position and height reference system --> [[Definitionen#CCRS|see Compound Coordinate Reference System]]).
* A reference coordinate system should '''not''' be changed within an instance file.
* A reference coordinate system should be defined once within <tt><gml:Envelope></tt>.

'''Recommendations for Germany:''' ''ETRS89 / UTM / Reference ellipsoid GRS80 + DHHN92''

'''CityGML Example:'''

<tt>
<gml:boundedBy>
<gml:Envelope srsDimension="3" srsName="'''urn:adv:crs:ETRS89_UTM32*DE_DHHN92_NH'''">
'''--> [[Definitionen#CCRS|see Compound Coordinate Reference System]]'''
<gml:lowerCorner srsDimension="3">458868.0 5438343.0 112.0 </gml:lowerCorner>
<gml:upperCorner srsDimension="3">458892.0 5438362.0 117.0 </gml:upperCorner>
</gml:Envelope>
</gml:boundedBy>
</tt>

'''ALKIS Example:'''

<tt>
<gml:boundedBy>
<gml:Envelope srsName="'''urn:adv:crs:ETRS89_UTM32'''">
<gml:pos>367456.554 5718128.391</gml:pos>
<gml:pos>367505.094 5718091.143</gml:pos>
</gml:Envelope>
</gml:boundedBy>
</tt>

see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#Spatial-Reference-System|Modeling Guide for 3D Objects - Part 1]]
-----
-----

=== <span id="ModelStructure">Model Structure</span> ===

The use of ''core:CityModel'' is not explicitely regulated in the specification and in the schema. The multiple use of ''core:CityModel'' is compliant to the schema and will be validated.
In order to avoid conflicts while importing CityGML models, it is recommended to use '''exactly one''' instance of ''core:CityModel'' as '''root element'''.

-----
-----

=== <span id="Heights">Heights</span> ===
The ''measuredHeight'' is the '''measured''' or '''computed''' difference between the lowest terrain intersection point and the highest roof point with the following properties:

* the ''measuredHeight'' is a '''simple''' attribute can not further specified and/or qualified;
* the ''measuredHeight'' is '''always''' related to the '''real''' building;
* the ''measuredHeight'' is '''independent of the LoD''' of the building;
* the '''computation''' of the ''measuredHeight'' should always base on the terrain model with the '''highest available resolution'''.

The following heights are valid for flat roofs, outshot roofs, gable roofs, hip roofs, jerkinhead roofs, mansard roofs, pyramid roof, shed roof, shells and domes:

[[image:Höhenangaben-01.png|800px]]

The following heights are valid for all kind of shed roofs:

[[image:Höhenangaben-02.png|800px]]

The following heights are valid for different roof overhangs:

[[image:Höhenangaben-03.png|800px]]

If you need absolute heights for the noted values you must define them as generic attributes (dimensioned ''gen:measureAttribute''):
* ''<gen:measureAttribute name="min height surface"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
* ''<gen:measureAttribute name="min height eaves"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
* ''<gen:measureAttribute name="max height eaves"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
* ''<gen:measureAttribute name="max height ridge"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
-----
-----

=== <span id="TerrainIntersectionLine">Terrain Intersection Line</span> ===
In CityGML the terrain intersection line is an attribute of a building or building part. It is generated by intersection of the building or building part with the terrain and has the following properties:

* a terrain intersection line can be '''measured''' or '''calculated''' ;
* if a terrain intersection line is calculated, the terrain model with the '''highest resolution available''' should be used;
* a terrain intersection line is an '''attribute''' of the '''building or building part''';
* outer building installations (''bldg:BuildingInstallation'') are '''taken into account''' from a terrain intersection line (see '''Figure A''');
* a terrain intersection line is a result of the intersection of buildings in the respective LoD and the most accurate available terrain. In CityGML it has no relation to the terrain used in a visualization and its resolution and accuracy.
* a terrain intersection line may consist of '''several independent parts''';
* a terrain intersection line '''need not be closed''';
* a terrain intersection line which does not exist in reality will '''not be taken into account''' (e.g. in the case of building parts ).
<table width="800px" border="0" cellspacing="6">
<tr align="middle">
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall a.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall b.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall c.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall d.png|200px]]
</td>
<tr align="middle" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
<td>
Figure C
</td>
<td>
Figure D
</td>
</tr>

</table>
-----
-----

=== <span id="AuskragendeBauelemente">Cantilevered Building Elements</span> ===
Cantilevered or projecting building elements are defined as '''parts''' of roofs, walls etc, which should '''not be considered in the volume calculation of the building'''. Cantilevered or projecting building elements are modeled as follows:
* as surface element(s) always separated from the volume-forming building element (see '''Figure A''')
* always as a surface element, if the thickness of the building element is less than 0.5 m (see '''Figure B''')
* always as a solid element, if the thickness of the building element is greater than 0.5 m (see '''Figure B''')
* in LoD2 always as a surface element, if the thickness of the building element is less than 0.5 m
* in LoD2 always as a solid element, if the thickness of the building element is greater than 0.5 m
* in LoD3 always in the best accuracy based on available information.


<table border="0" cellspacing="0">
<tr align="left" valign="center">
<td width="800">
[[image:AuskragendeBauelemente-1.png|800px]]
</td>
</tr>
<tr align="middle" valign="top">
<td width="500">
Figure A
</td>
</tr>
</table>

<table border="0" cellspacing="0">
<tr align="middle" valign="top">
<td width="500">
[[image:AuskragendeBauelemente-2.png|500px]]
</td>
</tr>
<tr align="middle" valign="top">
<td>
Figure B
</td>
</tr>
</table>

-----
-----

=== <span id="ClosedCoverageType"> Closed Coverage Type</span> ===
Buildings as parts of closed coverage type (applies to semi-detached and terrace houses also) can be modeled as follows:
* Buildings that are '''separated within the land register''' should be modeled as '''separate buildings'''.
<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="400">[[image:GeschlosseneBauweise-01-V01.png|400px]]</td><td width="400">[[image:GeschlosseneBauweise-04-V01.png|400px]]</td></tr><tr align="left" valign="center"><td width="400">Separate buildings of closed coverage type</td><td width="400">Terrace houses as separate buildings</td></tr></table>
* Buildings that are '''united within the land register''' should be modeled as '''one single building''' which can be subdivided into building parts (e.g. row of buildings, semi-detached or terrace houses).
<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="400">[[image:GeschlosseneBauweise-02-V01.png|400px]]</td><td width="400">[[image:GeschlosseneBauweise-03-V01.png|400px]]</td></tr><tr align="left" valign="center"><td width="400">Terrace houses as one single building</td><td width="400">Terrace houses as building parts</td></tr></table>
* Buildings '''without any land register information''' and for which the building detection provides '''no usable structures''' (e.g. based on flights) should be modeled as '''one single building'''.<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="400">[[image:GeschlosseneBauweise-02-V01.png|400px]]</td></tr><tr align="left" valign="center"><td width="400">Terrace houses as one single building</td></tr></table>

The modeling of '''boundary surfaces''' between buildings must satisfy the following geometric resp. semantic conditions:
* Common boundary surfaces may only '''be referenced within a building via Xlink''' (building-building part resp. building part - building part).

-----
-----

=== <span id="Addresses">Addresses</span> ===
* The CityGML specification allows to assign an address both to a building (''bldg:Building'', ''bldg:BuildingPart'') as well to a door (''bldg:Door''). It is recommended '''always to assign an address to a building''' (in any LoD) because doors are not available in LoD1 and LoD2.

* It is recommended to use the complete '''postal address'''.

* '''Multiple addresses''' can be assigned to one building.

* '''Umlauts''' are allowed in addresses (z.B. <span style="color:#008000">Würzburg☺</span>, <span style="color:#008000"> Wuerzburg☺</span>, <span style="color:#FF0000">Würzburg and Wuerzburg mixed ☹</span>).

'''General example:'''

Street: Hermann-von-Helmholtz-Platz
Number: 1
Zip Code: 76344
City: Eggenstein-Leopoldshafen

'''CityGML example:'''

<core:Address>
<core:xalAddress>
<xAL:AddressDetails>
<xAL:Locality Type="Town">
<xAL:LocalityName>'''Eggenstein-Leopoldshafen'''</xAL:LocalityName>
<xAL:Thoroughfare Type="Street">
<xAL:ThoroughfareNumber>'''1'''</xAL:ThoroughfareNumber>
<xAL:ThoroughfareName>'''Hermann-von-Helmholtz-Platz'''</xAL:ThoroughfareName>
</xAL:Thoroughfare>
<xAL:PostalCode>
<xAL:PostalCodeNumber>'''76344'''</xAL:PostalCodeNumber>
</xAL:PostalCode>
</xAL:Locality>
</xAL:AddressDetails>
</core:xalAddress>
</core:Address>
-----
-----

=== Codelists ===
Codelists for the CityGML 2.0 standard are available at "http://www.sig3d.org/codelists/standard".

The recommendations for codelists in this modeling guide refer to the proposal of the SIG3D. These codelists are availabe (in German only) at "http://www.sig3d.org/codelists/Handbuch-SIG3D" and relate to ALKIS.

This modeling guide refers to the following codelists:

*Building resp. building part (''bldg:Building / bldg:BuildingPart'')
**class http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_class.xml
**function http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_function.xml
**usage http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_usage.xml
**roofType http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_roofType.xml

*Building installations (''bldg:BuildingInstallation'')
**function http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml

-----
-----

=== Generic Attributes ===
Generic (user defined) attributes may be used to represent attributes which are '''not covered explicitly by the CityGML schema'''. Generic attributes must be used with care; they shall only be used if there is no appropriate attribute available in the overall CityGML schema. Otherwise, problems concerning semantic interoperability may arise. Interoperability of generic attributes is '''reduced to attribute values''' which can only be interpreted semantically by additional information.
The following attribute types are defined:

* ''stringAttribute'' - for arbitrary strings
* ''intAttribute'' - for dimensionless integer numbers
* ''doubleAttribute'' - for dimensionless floating point numbers
* ''dateAttribute'' - for dates with integer-valued year, month and day representation in the format YYYY-MM-DD (e.g. 2013-03-08)
* ''uriAttribute'' - represents a Uniform Resource Identifier Reference (URI) (e.g. a link to a document or a web site)
* ''measureAttribute'' - for dimensioned values (CityGML 2.0)

Attributes can be combined in CityGML 2.0 by generic attribute sets '''''genericAttributeSet''''' with an optional '''''codeSpace'''''. If the '''''codeSpace''''' attribute is present, then its value should identify an authority for the set, such as the organisation or community who defined its content. The generic attribute set may contain arbitrary generic attributes.

'''CityGML Examples'''

<gen:stringAttribute name="'''construction'''"><gen:value>'''concrete'''</gen:value></gen:stringAttribute>
<gen:intAttribute name="'''entries'''"><gen:value>'''3'''</gen:value></gen:intAttribute>
<gen:doubleAttribute name="'''floor area ratio FAR'''"><gen:value>'''0.33'''</gen:value></gen:doubleAttribute>
<gen:dateAttribute name="'''approval date'''"><gen:value>'''2012-03-09'''</gen:value></gen:dateAttribute>
<gen:uriAttribute name="'''website '''"><gen:value>'''http://www.sig3d.org'''</gen:value></gen:uriAttribute>
<gen:measureAttribute name="'''building width'''"><gen:value uom="#'''m'''">'''10.00'''</gen:value>/gen:measureAttribute>

<gen:genericAttributeSet name="'''Base Quantities'''">
<gen:measureAttribute name="Height"><gen:value uom="#m">9.00</gen:value></gen:measureAttribute>
<gen:measureAttribute name="Area"><gen:value uom="#m2">80.00</gen:value></gen:measureAttribute>
<gen:measureAttribute name="Volume"><gen:value uom="#m3">720.00</gen:value></gen:measureAttribute>
</gen:genericAttributeSet>
-----
-----

=== Geometry ===

There is '''no GML Profile''' for CityGML. This means that CityGML instance files will validate with every GML geometry. The specification '''restricts''' the usage of GML geometry classes (CityGML 2.0 Annex D "Overview of employed GML3 geometry classes).
CityGML references to the following geometry classes ('''CityGML 2.0 Annex D'''):

<table width="1200px" border="1" cellspacing="0">
<tr align="left">
<td width="250px">
'''Abstract Classes'''
</td>
<td width="250px">
'''Instantiated Classes'''
</td>
<td width="700px">
'''Further Limitations'''
</td>
</tr>
<tr>
<td width="250px" rowspan="2">
''gml:_Solid''
</td>
<td width="250px">
''gml:'''Solid'''''
</td>
<td>
only ''gml:OrientableSurface'', ''gml:Polygon'', ''gml:CompositeSurface'',

''tex:TexturedSurface'' (obsolete)
</td>
</tr>
<tr>
<td>
''gml:'''CompositeSolid'''''
</td>
<td>
no restriction
</td>
</tr>

<tr>
<td rowspan="6">
''gml:_Surface''
</td>
<td>
''gml:'''Polygon'''''
</td>
<td>
only ''gml:'''LinearRing''''' and ''gml:'''Ring''''' exclusively with ''gml:LineString'' or ''gml:CompositeCurve''
</td>
</tr>
<tr>

<td>
''gml:'''OrientableSurface'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>

<td>
''tex:TextureSurface''
</td>
<td>
obsolete
</td>
</tr>
<tr>

<td>
''gml:'''CompositeSurface'''''
</td>
<td>
only ''gml:OrientableSurface'', ''gml:Polygon'', ''gml:CompositeSurface''

''tex:TexturedSurface'' (veraltet)
</td>
</tr>
<tr>

<td>
''gml:'''TriangulatedSurface'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>

<td>
''gml:'''Tin'''''
</td>
<td>
no restriction
</td>
</tr>

<tr>
<td rowspan="2">
''gml:_Curve''
</td>
<td>
''gml:'''LineString'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>
<td>
''gml:'''CompositeCurve'''''
</td>
<td>
''gml:LineString'' and ''gml:CompositeCurve'' only
</td>
</tr>
<tr>
<td>
''gml:_GeometricPrimitive''
</td>
<td>
''gml:'''Point'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>

<td>
''gml:_Coverage''
</td>
<td>
''gml:'''RectifiedGridCoverage'''''
</td>
<td>
no restriction
</td>
</tr>


<tr>
<td rowspan="6">
''gml:_AbstractGeometricAggregate''
</td>
<td>
''gml:'''MultiSolid'''''
</td>
<td>
no restriction
</td>

</tr>
<tr>
<td>
''gml:'''MultiSurface'''''
</td>
<td>
only ''gml:OrientableSurface'', ''gml:Polygon'', ''gml:CompositeSurface'',

''tex:TexturedSurface'' (obsolete)
</td>
</tr>
<tr>
<td>
''gml:'''MultiCurve'''''
</td>
<td>
only ''gml:LineString'' and ''gml:CompositeCurve''
</td>
</tr>
<tr>
<td>
''gml:'''MultiPoint'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>
<td>
''gml:'''GeometricComplex'''''
</td>
<td>
restricted to connected linear networks
</td>
</tr>
<tr>
<td>
''gml:'''MultiGeometry'''''
</td>
<td>
restrictrions see allowed geometry types
</td>

</tr>

</table>

In order to keep the instance files small and to ensure an optimal editability of models, maximum flat polygons should be used, if appropriate with holes (inner rings).

-----
-----

=== File Name ===
It is recommended to use *.gml as file extension to distinguish CityGML files from other XML files.
-----
-----

== Modeling ==

=== Base Modeling ===
The base modeling includes the modeling of the '''building resp. building part''' itself in LoD1, with appropriate '''boundary surfaces''' in LoD2 and LoD3 and with '''windows and doors''' in LoD3. In addition, the basic modeling covers the general use of '''building installations'''.
-----
-----
==== <span id="Building">Building (''bldg:Building'')</span> ====

===== Definition =====
'''SIG3D:''' A free-standing self-supporting construction that is roofed, usually walled, and can be entered by humans and is normally designed to stand permanently in one place. It is intended for human occupancy (for example: a place of work or recreation), habitation and/or shelter of humans, animals or things.

'''ISO:''' Provision of shelter for its occupants or contents as one of its main purposes; usually partially or totally enclosed and designed to stand permanently in one place

===== CityGML Feature =====
''bldg:Building''

===== Geometry =====
'''''gml:Solid''''' see [[Handbuch für die Modellierung von 3D Objekten - Teil 1: Grundlagen (Regeln für valide GML Geometrie-Elemente in CityGML)#gml:Solid| Modeling Guide - Part 1]]

It is recommended to use '''''gml:Solid''''' depending on the LoD in the following way :

*In LoD1 a solid directly contains the bounding geometry ('''Figure A''')
*In LoD2 and LoD3 a solid contains external references (Xlinks) to the bounding geometry ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer bottom surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]] as well as [[#Türen|doors]] and [[#Fenster|windows]]) ('''Figure B''') ( see also conformance requirement no. 4 in chapter 10.3.9 of the CityGML V2.0 specification )


<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="400">
[[image:BuildingSolid-V1.png|300px]]
</td>
<td width="400">
[[image:BuildingSolidXlink.png|350px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
</tr>
</table>

'''''gml:MultiSurface''''' ''' <span style="color:#FF0000">(not recommended)</span>'''

'''''gml:MultiCurve''''' '''<span style="color:#FF0000">(not recommended)</span>'''

===== <span id="BuildingAttributes">Attributes</span> =====
; ''gml:id'' <span style="color:#008000">(mandatory)</span>
: from GML version 3.2 onwards an id is mandatory
; ''gml:name'' <span style="color:#00FF00">(recommended, if available in the underlying land register)</span>
:'name' is the proper name or the name of the building.
; ''bldg:class'' (LoD1, LoD2, LoD3)
:The attribute ''bldg:class'' allows an unspecified classification of the building; no suggestion from the SIG3D;
; ''bldg:function'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:The 'function' of a building is the predominantly functional significance of the building at the date of data collection ( principle of dominance ); see also in the SIG3D code lists.
; ''bldg:usage'' (LoD1, LoD2, LoD3) <span style="color:#0000FF">(conditionally recommended)</span>
:The 'usage' of a building describes the use of the building and contains the respective percentage usage share of the total use.
; ''bldg:yearOfConstruction'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:The 'yearOfConstruction' is the year of completion of the construction or alteration of the building;
; ''bldg:yearOfDemolition'' (LoD1, LoD2, LoD3)
:The 'yearOfDemolition' is the year of deconstruction of the building;
;''bldg:roofType'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:'Roof type' describes the characteristic shape of the roof; see also in the code list of the SIG3D
; ''bldg:measuredHeight'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:'Measured height' is the difference in [m] between the highest point of the roof structure and the defined footprint of the building; see also [[#Heights|Heights]]
; ''bldg:storeysAboveGround'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended, if available in the underlying land register)</span>
:'storeys above ground' is the number of above-ground floors
; ''bldg:storeysBelowGround'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended, if available in the underlying land register)</span>
:'storeys below ground' is the number of underground floors
; ''bldg:storeysHeightsAboveGround'' (LoD1, LoD2, LoD3)
:Height between two consecutive floors of the above-ground floors
; ''bldg:storeysHeightsBelowGround'' (LoD1, LoD2, LoD3)
:Height between two consecutive floors of the underground floors
; ''bldg:lodXSolid'' (LoD1, LoD2, LoD3)
:LoDX geometry (volume)of the building
; ''bldg:lodXMultiSurface'' (LoD1, LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:LoDX geometry (surface) of the building
; ''bldg:lodYMultiCurve'' (LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:LoDY geometry (curve) of the building
; ''bldg:lodXTerrainIntersection'' (LoD1, LoD2, LoD3)
:LoDX geometry (curve) of the [[#Terrain Intersection Line|terrain intersection line]] of the building
; ''bldg:outerBuildingInstallation'' (LoD2, LoD3)
:Relation to LoD2/LoD3 building installation
; ''bldg:boundedBy'' (LoD2, LoD3)
: Relation to boundary surfaces ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer floor surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]])
; ''bldg:consistsOfBuildingPart'' (LoD1, LoD2, LoD3)
:Relation to LoD1/LoD2/LoD3 building parts
; ''bldg:address'' (LoD1, LoD2, LoD3)
:Relation to one or more building addresses

===== Examples =====

<table width="1200px" border="0" cellspacing="6">
<tr align="left">
<td colspan="6">
'''Detached family house'''
</td>
</tr>
<tr align="middle">
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-real.png|200px]]
</td>

<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD0.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD1.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD2.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD3.png|200px]]
</td>
<tr align="middle" valign="top">
<td>
Real Building
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

</table>
-----
-----

==== <span id="Gebäude">Building Part (''bldg:BuildingPart'')</span> ====

===== Definition =====
'''SIG3D:''' A building part is a sub-division of a building that is homogeneous related to its physical, functional or temporal aspects and may be considered as a building.

The subdivision of a building can be done by different criteria, e.g.
* structural like number of floors, roof type, height, construction method,
* administrative like building function, ownership, year of construction.

Building parts (''bldg:BuildingParts'') must satisfy the following conditions ( necessary conditions ):
* A building part '''always''' has a relation (bldg:consistsOfBuildingPart) to '''exactly one''' building:
* Buildings and building parts '''touch each other''' planar or linear-shaped,
* Building parts must be '''"connected to ground"''' and can have the following '''properties''' ( for example, storeys are no building parts ):
** Building parts may have different '''building attributes''' ( e.g. function, roof type ),
** Building parts may have an address that '''differs''' from the address of the building,
** The geometry of building parts (''bldg:BuildingParts'') must be modeled in a way that both the '''volume''' and the '''surfaces''' of the boundary surfaces ( wall surfaces, roof surfaces and ground surfaces ) correspond to the real conditions ([[#BuildingPart/Geometry|see chapter Building Part/Geometry]]),
** If a building part is emphasized as the '''main part of the building''', its semantics and geometry can be modeled in the parent building,
** Building parts will not be subdivided into further building parts.

===== CityGML Feature =====

''bldg:BuildingPart''

===== <span id="BuildingPart/Geometry"> Geometry</span> =====
;'''''gml:Solid'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:Solid|Modeling Guide for 3D Objects - Part 1]]

:It is recommended to use '''''gml:Solid''''' depending on the LoD in the following way :

:*In LoD1 a solid directly contains the bounding geometry ('''Figure A''')
:*In LoD2 and LoD3 a solid contains external references (Xlinks) to the bounding geometry ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer bottom surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]] as well as [[#Türen|doors]] and [[#Fenster|windows]]). '''In real nonexistent surfaces''' are modeled as closure surfaces ('''Figure B''').
:*In LoD2 a solid contains external references (Xlinks) to the real bounding geometry. '''In real nonexistent surfaces''' are modeled as closure surfaces and assigned directly to the building part ('''Figure C''').


<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD1.png|200px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-FallB.png|200px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-FallB.png|200px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD1-gedreht.png|300px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-gedreht-FallB.png|300px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-gedreht-FallC.png|300px]]
</td>
</tr>

<tr align="left" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
<td>
Figure C
</td>

</tr>
</table>

; ''bldg:boundedBy'' (LoD2, LoD3)
: Relation to boundary surfaces ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer floor surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]])

'''''gml:MultiSurface''''' ''' <span style="color:#FF0000">(not recommended)</span>'''

'''''gml:MultiCurve''''' '''<span style="color:#FF0000">(not recommended)</span>'''

===== <span id="BuildingAttribute">Attributes</span> =====
Since the building part is derived from the building, all attributes of the building are also available for the building part (see also [[#BuildingAttribute|Building Attribute]]).

'''Exception:''' ''bldg:consistsOfBuildingPart''

===== Examples =====
<table width="1100px" border="0" cellspacing="0">
<tr align="left">
<td>
'''Office with factory hall'''
</td>
<td>

</td>
</tr>
<tr align="left">
<td width="550px" valign="bottom">
[[image:Buero-Werkshalle-01.png|500px]]
</td>
<td width="550px" valign="bottom">

</td>

</tr>
<tr align="left">
<td>
"structurally distinct" building parts → "Office" as function of BuildingPart 1 ; "Factory Hall" as function of BuildingPart 2
</td>
<td>

</td>
</tr>
</table>

<table width="1100px" border="0" cellspacing="0">
<tr align="left">
<td>
'''Detached house with staggered shed roof'''
</td>
<td>
'''House with a projecting floor'''
</td>
</tr>
<tr align="left">
<td width="550px" valign="bottom">
[[image:FJK-Haus-BuildingParts.png|500px]]
</td>
<td width="550px" valign="bottom">
[[image:FJK-Haus-BuildingParts-03.png|500px]]
</td>

</tr>
<tr align="left">
<td>
No "structurally distinct" building parts → roofType "staggered shed roof"
</td>
<td>
No "structurally distinct" building parts; 1 building part not "connected to ground"
</td>
</tr>
</table>

'''Examples with overarching building parts'''

Variante 1
[[image:Variante-01-V2-red.png|500px]]

'''Variante 2'''
[[image:Variante-02-V1-red.png|500px]]

Variante 3
[[image:Variante-03-V2-red.png|500px]]

-----
-----

==== <span id="BuildingInstallation">Building Installations (''bldg:BuildingInstallation'')</span> ====

===== Definition =====
'''SIG3D:''' Permanently installed parts of the buildings outer shell which are accessory for the building structure including loggia, dormer, etc. Doors and windows are modeled by the corresponding CityGML classes.

===== CityGML Feature =====

*'''LOD1:''' not available
*'''LOD2:''' ''bldg:BuildingInstallation''
*'''LOD3:''' ''bldg:BuildingInstallation''

===== <span id="BuildingInstallation/Geometry"> Geometry</span> =====
;'''''gml:Geometry'''''
:'''''gml:Geometry''''' allows '''points''', '''lines''', '''areas''', '''volumes''' as well as any combination of these elements.
:The use of points is '''<span style="color:#FF0000">not recommended</span>'''. <br />
:The use of lines is only '''<span style="color:#0000FF">recommenced under certain circumstances</span>''', because not all applications are able process this geometry.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:Haus-mit-Antenne-V1.png|300px]]
</td>
<td width="300">
[[image:Haus-mit-SolarPanel-V1.png|300px]]
</td>
<td width="300">
[[image:Haus-mit-Kamin-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
Lines (e.g. Antenna)
</td>
<td width="300">
Surfaces (e.g. Solar Panel)
</td>
<td width="300">
Volumes (e.g. Chimney)
</td>
</tr>
</table>

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:Haus-mit-SatellitenAntenne-V2.png|300px]]
</td>
<td width="300">
[[image:LoD2-Haus-Treppe-V2-MultiGeo-V1.png|300px]]
</td>
<td width="300">
[[image:Haus-mit-Balkon-V2.png|300px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
Lines and surfaces (e.g. satellite dish)
</td>
<td width="300">
Lines and surfaces resp. surfaces and volumes (e.g. stair and porch)
</td>
<td width="300">
Lines, surfaces und volumes (e.g. balcony)
</td>
</tr>
</table>

; ''bldg:boundedBy'' (LoD2, LoD3)
: Relation to boundary surfaces ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer floor surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]]) → see also [[#ErweiterteModellierung|Extended Modeling]]

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-Solid-V1.png|200px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-V1.png|320px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-Solid-V1-explode.png|200px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-V1-explode.png|320px]]
</td>
</tr>

<tr align="left" valign="center">
<td width="300">
Building with a small ridge turret (modeled as building installation with geometry)
</td>
<td width="500">
Building with a tower (modeled as building installation with boundary surfaces)
</td>
</tr>
</table>

===== <span id="BuildingInstallation/Attributes">Attributes</span> =====
; ''gml:id'' <span style="color:#008000">(mandatory)</span>
: from GML version 3.2 onwards an id is mandatory
; ''bldg:class'' (LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:The attribute ''bldg:class'' allows an unspecified classification of the building installation; no suggestion from the SIG3D;
; ''bldg:function'' (LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:The 'function' of a building installation is the predominantly functional significance of the building installation at the date of data collection ( principle of dominance ); see also in the SIG3D code lists.
; ''bldg:usage'' (LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:no suggestion from the SIG3D;
; ''bldg:lodXGeometry'' (LoD2, LoD3)
:LoDX geometry of the building installation;

===== <span id="BuildingInstallation/Examples">Examples</span> =====
<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-Solid-LOD1-V1.png|300px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-Solid-LOD2-V1.png|300px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-Solid-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
LoD1: no building installation
</td>
<td width="300">
LoD2: simplified building installation
</td>
<td width="300">
LoD3: detailed building installation
</td>
</tr>
</table>
<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-LOD1-V1.png|400px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-V1.png|400px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-LOD3-V1.png|400px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
LoD1: no building installation
</td>
<td width="300">
LoD2: simplified building installation
</td>
<td width="300">
LoD3: detailed building installation
</td>
</tr>
</table>

------
------

==== <span id="GroundSurfaces">Ground Surfaces (''bldg:GroundSurface'')</span> ====

===== Definition =====
'''SIG3D:''' Exterior, lower boundary surface of a building, building part or building installation against soil or water ( e.g. foundation ).

===== CityGML Feature =====

*'''LoD1:''' not available
*'''LoD2:''' ''bldg:GroundSurface''
*'''LoD3:''' ''bldg:GroundSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:Solid|Modeling Guide for 3D Objects - Part 1]]
* A '''ground surface''' consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.

[[image:GroundSurface-Flaech-Volumen.png|600px]]

* The '''elevation''' of the ground surface depends on the availability of data:
** If there is information available about cellars, the elevation of the ground surface is set to the lower edge of the floor of the cellar ('''Figure A''');
** If the ground surface of the building, building part or building installation is generated by an intersection with the terrain, the elevation of the (horizontal) ground surface is set to the lowest absolute height of the corresponding terrain intersection line ('''Figure B''');
** It is <span style="color:#FF0000">not recommeded</span> to generate the ground surface of the building, building part or building installation directly from an intersection with the terrain ('''Figure C''');


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:GroundSurface-Skizze-5-V2.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-Skizze-6-V2.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-Skizze-7-V2.png|250px]]
</td>
<tr align="left" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
<td>
Figure C
</td>
</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>

===== Attribute =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry of the base area
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry of the base area
;''bldg:opening'' <span style="color:#FF0000">not recommended</span>
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:GroundSurface-0-V1.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-1-V1.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-2-V1.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-3-V1.png|250px]]
</td>
<tr align="left" valign="top">
<td>
Building without cellar and one floor slab
(One bldg:GroundSurface)
</td>
<td>
Building with cellar and one floor slab
(One bldg:GroundSurface)
</td>
<td>
Building with partial cellar and two different floor slabs
(Two bldg:GroundSurface)
</td>
<td>
Building with cellar and ramp
(Two bldg:GroundSurface)
</td>
</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:GroundSurface-5-V2.png|250px]]
</td>
<td width="253">
[[image:GroundSurface-6-V2.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-7-V2.png|250px]]
</td>
<tr align="left" valign="top">
<td>
Building with ground surface at lower edge of floor cellar
(One bldg:GroundSurface)
</td>
<td>
Building with ground surface at lowest absolute height of the corresponding terrain intersection line
(One bldg:GroundSurface)
</td>
<td>
Building with ground surface based on intersection with the terrain
(One bldg:GroundSurface) <span style="color:#FF0000">not recommended</span>

</td>

</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>
-----
-----

==== <span id="WallSurfaces">Wall Surfaces (''bldg:WallSurface'')</span> ====

===== Definition =====
'''SIG3D:''' A wall surface is an exterior, lateral boundary surface of a building, building part or building installation.

'''ISO:''' A wall is a vertical construction that bounds or subdivides a space and usually fulfils a loadbearing or retaining function.

The normals of the wall surfaces should generally lie in the horizontal ( up to 45 degrees ).

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:WallSurface''
* '''LoD3:''' ''bldg:WallSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* A '''wall surface''' surface consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.

[[image:WallSurface-Flaechen-Volumen.png|600px]]

* '''Wall projections''', which do not limit the volume of the building will be modeled according to the rules for
'''[[#AuskragendeBauelemente|Cantilevered building elements]]'''.



* A '''wall surface''' ''must'' consist of '''several surfaces ( SurfaceMember )''' if :
** a wall surfaces has different '''colors''' or '''textures'''<table border="0" cellspacing="6"><tr align="left" valign="top"><td width="300">[[image:WallSurface-mit-Farben-V1.png|300px]]</td><td width="300">[[image:WallSurface-mit-Texturen-V1.png|300px]]</td><tr align="left" valign="top"><td>4 wall surfaces with 3 areas each (1 area in "orange"; 2 areas in "beige")(4 bldg:WallSurface)</td><td>4 wall surfaces with 2 areas each (1 area with texture "plaster"; 1 area with texture "sandstone") (4 bldg:WallSurface)</td></table>
** a wall surface is '''nonplanar'''<table border="0" cellspacing="6"><tr align="left" valign="top"><td width="300">[[image:WallSurface-Rund-V1.png|300px]]</td><td width="300">[[image:WallSurface-Laibungen-V1.png|300px]]</td><tr align="left" valign="top"><td>5 wall surfaces; 4 wall surfaces with 1 surface each and 1 wall surface (circular wall) with 6 surfaces (4 bldg:WallSurface)</td><td>Front wall as 1 wall surface consisting of 4 surfaces (revealing areas); right wall as 1 wall surface consisting of 13 surfaces (12 revealing areas)</td></table>
* A '''wall surface''' ''might'' consist of '''several surfaces ( SurfaceMember )''' if :
** it is intended to indicate a '''storey structure'''<table border="0" cellspacing="6"><tr align="left" valign="top"><td width="300">[[image:WallSurface-ohne-Stockwerke-V1.png|300px]]</td><td width="300">[[image:WallSurface-mit-Stockwerke-V1.png|300px]]</td><tr align="left" valign="top"><td>4 wall surfaces with 1 surface each (4 bldg:WallSurface)</td><td>4 wall surfaces with 3 surfaces each (ground floor, upper floor and top floor) (4 bldg:WallSurface)</td></table>

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry of the wall
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry of the wall
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====
<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:WallSurface-0-V2.png|250px|link=WallSurface-0-Animation]]
</td>
<td width="250">
[[image:WallSurface-1-V2.png|250px|link=WallSurface-1-Animation]]
</td>
<td width="250">
[[image:WallSurface-2-V2.png|250px|link=WallSurface-2-Animation]]
</td>
<tr align="left" valign="top">
<td>
A wall surface with 4 surfaces
(1 bldg:WallSurface)
<span style="color:#FF0000">not recommended</span>
</td>
<td>
4 wall surfaces with 1 surface each
(4 bldg:WallSurface)
</td>
<td>
4 wall surfaces (3 planar walls with 1 surface each and 1 circular wall with 12 surfaces)
(4 bldg:WallSurface)
</td>
</tr>
</table>

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:WallSurface-3-V2.png|250px]]
</td>
<td width="250">
[[image:WallSurface-4-V2.png|250px]]
</td>
<tr align="left" valign="top">
<td>
1 wall surface with elliptic or circular layout
(1 bldg:WallSurface)
</td>
<td>
5 wall surfaces by staggered facades
(5 bldg:WallSurface)
</td>
</table>
-----
-----

==== <span id="RoofSurfaces">Roof Surfaces (''bldg:RoofSurface'')</span> ====

===== Definition =====
'''SIG3D:''' A roof surface is a exterior, upper boundary surface of a building, building part or building installation, whose primary function is to protect from the effects of weather.
'''ISO:''' A roof is a construction that encloses a building from above

The normals of a roof should generally lie in the vertical.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:RoofSurface''
* '''LoD3:''' ''bldg:RoofSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* A '''roof surface''' surface consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.

[[image:RoofSurface-Flaechen-Volumen.png|600px]]

* '''Roof projections''', which do not limit the volume of the building will be modeled according to the rules for '''[[#AuskragendeBauelemente|cantilevered building elements]]'''.

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry of the roof
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry of the roof
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Gable Roof'''
</td>
<td width="250">
'''Gable Roof'''
</td>
<td width="250">
'''Mixed Roof'''
</td>
<td width="250">
'''Tent Roof'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:RoofSurface-0-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-1-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-2-V1.png|220px]]
</td>
<td width="250">
[[image:RoofSurface-3-V1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 roof surface with 2 surfaces
(1 bldg:RoofSurface) <span style="color:#FF0000">not recommended</span>
</td>
<td>
2 roof surfaces with 1 surface each
(2 bldg:RoofSurface)
</td>
<td>
3 roof surfaces ( 2 planar roof surfaces with 1 surface each and 1 conical roof area with 12 surfaces )
(3 bldg:RoofSurface)
</td>
<td>
1 conical roof area with 24 surfaces
(1 bldg:RoofSurface)
</td>
</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Jerkinhead Roof'''
</td>
<td width="250">
'''Gambrel Roof'''
</td>
<td width="250">
'''Arch Roof'''
</td>
<td width="250">
'''Dome Roof'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:RoofSurface-4-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-5-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-6-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-8-V1.png|220px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
4 roof surfaces
(4 bldg:RoofSurface)
</td>
<td>
4 roof surfaces
(4 bldg:RoofSurface)
</td>
<td>
1 roof surface with 12 surfaces
(1 bldg:RoofSurface)
</td>
<td>
1 roof surface with 264 surfaces
(1 bldg:RoofSurface)
</td>
</tr>
</table>

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Shed Roof I'''
</td>
<td width="250">
'''Shed Roof II'''
</td>
<td width="250">

</td>
<td width="250">

</td>

</tr>
<tr align="left" valign="top">
<td width="250">
[[image:RoofSurface-9-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-10-V1.png|250px]]
</td>
<td width="250">

</td>
<td width="250">

</td>
</tr>
<tr align="left" valign="top">
<td>
5 roof surfaces
(5 bldg:RoofSurface)
</td>
<td>
10 roof surfaces
(10 bldg:RoofSurface)
</td>
<td>

</td>
<td>

</td>
</tr>
</table>
-----
-----

==== <span id="OuterFloorSurfaces">Outer Floor Surfaces(''bldg:OuterFloorSurface'')</span> ====

===== Definition =====
'''SIG3D:''' Exterior, upper boundary surface of a building, building part or building installation which is not a roof.

The normals of an outer floor surface should generally be vertical directed upwards.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:OuterFloorSurface''
* '''LoD3:''' ''bldg:OuterFloorSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* An outer floor surface consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="400">
[[image:OuterFloorSurface-Uebersicht.png|300px]]
</td>
<td width="600">
[[image:OuterFloorSurface-Flaechen-Volumen.png|600px]]
</td>
</table>

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Roof terrace'''
</td>
<td width="250">
'''Loggia'''
</td>
<td width="250">
'''Roof terrace'''
</td>
</tr>
<tr align="left" valign="top">
<td width="300">
[[image:OuterFloorSurface-01-V1.png|300px]]
</td>
<td width="300">
[[image:OuterFloorSurface-02-V1.png|300px]]
</td>
<td width="300">
[[image:OuterFloorSurface-03-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 OuterFloorSurface
</td>
<td>
1 OuterFloorSurface
</td>
<td>
1 OuterFloorSurface
</td>
</tr>
</table>

-----
-----

==== <span id="OuterCeilingSurface">Outer Ceiling Surface(''bldg:OuterCeilingSurface'')</span> ====

===== Definition =====
'''SIG3D:''' Exterior, lower boundary surface of a building, building part or building installation against air.

The normals of an outer ceiling surface should generally be vertical directed downwards.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:OuterCeilingSurface''
* '''LoD3:''' ''bldg:OuterCeilingSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* An '''outer ceiling surface''' consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="400">
[[image:OuterFloorSurface-Uebersicht.png|300px]]
</td>
<td width="600">
[[image:OuterCeilingSurface-Flaechen-Volumen.png|600px]]
</td>
</table>

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Passage'''
</td>
<td width="250">
'''Loggia'''
</td>
<td width="250">
'''Cantilevered floor'''
</td>
</tr>
<tr align="left" valign="top">
<td width="300">
[[image:OuterCeilingSurface-02-V1.png|300px]]
</td>
<td width="300">
[[image:OuterCeilingSurface-01-V1.png|300px]]
</td>
<td width="300">
[[image:OuterCeilingSurface-03-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 OuterCeilingSurface
</td>
<td>
1 OuterCeilingSurface
</td>
<td>
1 OuterCeilingSurface
</td>
</tr>
</table>

-----
-----

==== <span id="VitualBoundarySurface">Virtual Boundary Surface (''bldg:ClosureSurface'')</span>====

===== Definition =====
'''SIG3D:''' Exterior or interior boundary surface providing virtual boundaries, typically used to seal holes in volumetric objects.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:ClosureSurface''
* '''LoD3:''' ''bldg:ClosureSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* A '''closure surface''' consists only of virtual ( imaginary ) surfaces which are '''visible from the outside''' of the building, building part or building installation.

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:opening'' <span style="color:#FF0000">not recommended</span>
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Open barn'''
</td>
<td width="250">
'''Railway platform hall'''
</td>
<td width="250">
'''Parking garage'''
</td>
</tr>
<tr align="left" valign="top">
<td width="300">
[[image:ClosureSurface-01-V1.png|300px]]
</td>
<td width="300">
[[image:ClosureSurface-03-V1.png|300px]]
</td>
<td width="300">
[[image:ClosureSurface-02-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 ClosureSurface
</td>
<td>
2 ClosureSurface
</td>
<td>
28 ClosureSurface
</td>
</tr>
</table>

-----
-----

==== <span id="Doors">Doors (''bldg:Door'')</span> ====

===== Definition =====
'''ISO 6707-1:''' Construction for closing an opening intended primarily for access or egress or both.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' not available
* '''LoD3:''' ''bldg:Door''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]

* A '''door''' consists only of surfaces which are either '''visible from the outside''' of the building, building part or building installation ( case A, B or C ) or consists of '''solids''' ( case D ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:TerrassenTuer-Detail-0.png|250px]]
</td>
<td width="250">
[[image:TerrassenTuer-Detail-0-Texture.png|250px]]
</td>
<td width="250">
[[image:TerrassenTuer-Detail-1-Flaeche.png|250px]]
</td>
<td width="250">
[[image:TerrassenTuer-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
[[image:TerrassenTuer-Schnitt-Detail-0.png|250px]]
</td>
<td>
[[image:TerrassenTuer-Schnitt-Detail-0-Texture.png|250px]]
</td>
<td>
[[image:TerrassenTuer-Schnitt-Detail-1-Flaeche.png|250px]]
</td>
<td>
[[image:TerrassenTuer-Schnitt-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Door as a simple surface)
</td>
<td>
'''Case B''' (Door as a textured surface)
</td>
<td>
'''Case C''' (Door modeled in detail with surfaces only visible from the outside)
</td>
<td>
'''Case D''' (Door as a solid)
</td>
</tr>
</table>

* In order to ensure a closed outer shell of the building, the doors should '''not''' be modeled '''in an opened state''' ( case A ) but '''in closed condition''' ( case B ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="500">
[[image:Tuer-offen-red-v1.png|500px]]
</td>
<td width="500">
[[image:Tuer-zu-red-v1.png|500px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Doors opened)
</td>
<td>
'''Case B''' (Doors closed)
</td>
</tr>
</table>

===== Attributes =====
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:address''
:points to the address of the door

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Simple Doors'''
</td>
<td width="250">
'''Simple Doors with Embrasure'''
</td>
<td width="250">
'''Doors modeled in detail'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:Beispiel-Tueren-GanzEinfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Tueren-Einfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Tueren-Komplex-Red-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
Number of Polygons (Complete Model) = 19
</td>
<td>
Number of Polygons (Complete Model) = 128
</td>
<td>
Number of Polygons (Complete Model) = 3498
</td>
</tr>
</table>

----
----

==== <span id="Windows">Windows (''bldg:Window'')</span> ====

===== Definition =====
'''SIG3D:''' Construction for closing an opening in a wall or roof, primarily intended to admit light and / or provide ventilation (cf. ISO 6707).

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' not available
* '''LoD3:''' ''bldg:Window''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]

* A '''window''' consists only of surfaces which are either '''visible from the outside''' of the building, building part or building installation ( case A, B or C ) or consists of '''solids''' ( case D ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:RechteckFenster-Detail-0.png|250px]]
</td>
<td width="250">
[[image:RechteckFenster-Detail-0-Texture.png|250px]]
</td>
<td width="250">
[[image:RechteckFenster-Detail-1-Flaeche.png|250px]]
</td>
<td width="250">
[[image:RechteckFenster-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
[[image:RechteckFenster-Schnitt-Detail-0.png|250px]]
</td>
<td>
[[image:RechteckFenster-Schnitt-Detail-0-Texture.png|250px]]
</td>
<td>
[[image:RechteckFenster-Schnitt-Detail-1-Flaeche.png|250px]]
</td>
<td>
[[image:RechteckFenster-Schnitt-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Window as a simple surface)
</td>
<td>
'''Case B''' (Window as a textured surface)
</td>
<td>
'''Case C''' (Window modeled in detail with surfaces only visible from the outside)
</td>
<td>
'''Case D''' (Window as a solid)
</td>
</tr>
</table>

* In order to ensure a closed outer shell of the building, the windows should '''not''' be modeled '''in an opened state''' ( case A ) but '''in closed condition''' ( case B ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="500">
[[image:Fenster-offen-red-v1.png|500px]]
</td>
<td width="500">
[[image:Fenster-geschlossen-red-v1.png|500px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Windows opened)
</td>
<td>
'''Case B''' (Windows closed)
</td>
</tr>
</table>

===== Attributes =====
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry

===== Examples =====

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Simple Window'''
</td>
<td width="250">
'''Simple Window with Embrasure'''
</td>
<td width="250">
'''Detailled Window'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:Beispiel-Fenster-GanzEinfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Fenster-Einfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Fenster-Komplex-Red-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
Number of Polygons (Complete Model) = 28
</td>
<td>
Number of Polygons (Complete Model) = 412
</td>
<td>
Number of Polygons (Complete Model) = 6269
</td>
</tr>
</table>

----
----

=== <span id ="ExtendedModeling">Extended Modeling</span> ===
The Extended Modeling covers the modeling of frequently appearing '''architectural building components''' which significantly form the building's outer appearence. These building components are modeled as '''building installations''' as a general rule.
-----
-----
==== <span id="Balconies">Balconies</span> ====

===== Definition =====
'''SIG3D:''' A '''Balcony''' is a platform attached to a building which lies above the terrain level and projects from the building structure.
It is supported by columns or console brackets, and enclosed with a balustrade [cit. en. Wikipedia]. The word's origin lies in the Italian word "balcone", which itself originates from the old-high-german word "balcho".

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====

*'''''gml:Geometry'' <span style="color:#00FF00">recommended</span>'''
** '''Threshold LOD2:'''
*** Modeling only, if the balcony's depth >= 0.5 m;
**** Plane ground-area, if the component's thickness <= 0.5 m;
**** Plane side-walls, if the component's thickness <= 0.5 m;
** '''Threshold LOD3:'''
*** Modeling only, if the balcony's depth >= 0.2 m;
**** Plane ground-Area, if the component's thickness <= 0.2 m;
**** Plane side-walls, if the component's thickness <= 0.2 m;
** '''Modeling principle'''
*** The building contains all geometry-containing border surfaces.
*** The balcony is modeled as a '''Building Installation with Geometry'''. That is without semantic differentiation.
*** The building's volume references (Xlink) to the corresponding boarder surfaces.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Balkon-Prinzip.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modeling principle of a balcony</td>
</tr>
</table>

*'''''bldg:boundedBy'' <span style="color:#FF0000">not recommended</span>'''

===== Attributes =====
;''bldg:function''
:Balcony'' (1000); see SIG 3D Codelistrecommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#FF0000">'''not recommended:'''</span> A Balcony is considered as '''one''' building component which is semantically not subdivided any further.

===== Examples =====

<table width="1200px" border="1" cellspacing="0" >

<tr align="left">
<td colspan="6">
'''Balconies'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Real Building
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td rowspan="2" width="200px" valign="top">
[[image:KHH-3-Balkone-01-red.JPG|200px]]
</td>

<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD0.png|200px]]
</td>
<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD1.png|200px]]
</td>
<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD2.png|200px]]
</td>
<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD3.png|200px]]
</td>
</tr>

<tr align="middle">
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/6/6e/KHH-3-Balkone-LOD0-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/c/ce/KHH-3-Balkone-LOD1-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/a/ac/KHH-3-Balkone-LOD2-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/d/d0/KHH-3-Balkone-LOD3-V01.gml CityGML download]
</td>
</tr>


<tr align="left">
<td colspan="6">
Above terrain level, projected from the building structure --> Balcony
</td>
</tr>
</table>

<table width="1200px" border="1" cellspacing="0">

<tr align="middle">
<td rowspan="2" width="200px" valign="top">
[[image:Eckbalkon-03-red.png|200px]]
</td>

<td width="200px" valign="top">
[[image:Eckbalkon-LOD0-01.png|200px]]
</td>
<td width="200px" valign="top">
[[image:Eckbalkon-LOD1-01.png|200px]]
</td>
<td width="200px" valign="top">
[[image:Eckbalkon-LOD2-01.png|200px]]
</td>
<td width="200px" valign="top">
[[image:Eckbalkon-LOD3-02.png|200px]]
</td>

<tr align="middle">
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/9/96/Eckbalkon-LOD0-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/4/4a/Eckbalkon-LOD1-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/7/77/Eckbalkon-LOD2-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/5/56/Eckbalkon-LOD3-V01.gml CityGML download]
</td>

</tr>
<tr align="left">
<td colspan="6">
Above terrain level, partly projected from the building structure, not bounded by 3 walls --> Balcony (no Loggia)
</td>
</tr>
</table>

-----
-----




==== Loggias ====

===== Definition =====
'''SIG3D:''' A '''Loggia''' is an enclosed on top exterior room within the building footprint, which is surrounded by '''3''' walls at full storey height. From an architectonical point of view, a '''Loggia''' (from the Italian) is a room within a building, which opens to the exterior area by means of archs or other constructional appliances. At ground floor level, Loggias create a passage between the interior area and the exterior area. At upper floor levels, Loggias are used as connection passages or as outdoor seating.

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">not recommended</span>'''

*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** '''Threshold LOD2:'''
*** Modeling only, if the Loggia's depth >= 0.5 m;
** '''Threshold LOD3:'''
*** Modeling only, if the Loggia's depth >= 0.2 m;
** '''Modeling Principle'''
*** The building contains all geometry-containing boundary surfaces

*** The Loggia (BuildingInstallation) '''references (Xlink)''' to the building's corresponding boundary surfaces. If the Loggia's floor is not part of the exterior building structure, it will be modeled as boundary surface at the building installation.
*** The building's volume references (Xlink) to the building's corresponding boundary surfaces.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Loggia-Prinzip-v2.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modeling Principle of a Loggia</td>
</tr>
</table>


===== Attributes =====
;''bldg:function''
:Loggia (1001); see SIG 3D Codelist recommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> A Loggia is considered as a building component which semantically consists of the building's boundary surfaces and possibly an exterior floor surface.

===== Examples =====

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="left">
<td colspan="6">
'''Loggien'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Real Building
</td>
<td>
ALKIS (German Cadastral Data)
</td>
<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z09.png|200px]]
Interior Loggia
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z09.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z09.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_01.jpg|200px]]
[http://quality.citygmlwiki.org/images/9/9a/Loggia-01-CityGML-LOD2-V1.gml CityGML download]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z12.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z12.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_01.jpg|200px]]
[http://quality.citygmlwiki.org/images/9/9a/Loggia-01-CityGML-LOD2-V1.gml CityGML download]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z13.png|200px]]
Partly set back ground floor
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z13.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z14.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_02.jpg|200px]]
[http://quality.citygmlwiki.org/images/6/63/Loggia-02-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z13.png|200px]]
Multi-storey building with interior Loggias
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z15.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z14.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_03.jpg.png|200px]]
[http://quality.citygmlwiki.org/images/c/c2/Loggia-03-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z16.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z16.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_03.jpg.png|200px]]
[http://quality.citygmlwiki.org/images/c/c2/Loggia-03-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z17.png|200px]]
Multi-storey building, Loggias across the whole front-width and height
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z17.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z17.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_04.jpg|200px]]
[http://quality.citygmlwiki.org/images/d/d8/Loggia-04-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z18.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z17.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_04.jpg|200px]]
[http://quality.citygmlwiki.org/images/d/d8/Loggia-04-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Loggien_halbe_Breite-05-Foto-V1.png|200px]]
Loggias across half the front-width (row house)
</td>
<td width="200px" valign="bottom">
[[image:|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:|200px]]
Kamen Am Langen Kamp 25
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_05.jpg|200px]]
[http://quality.citygmlwiki.org/images/a/a9/Loggia-05-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Vorgebaute_Loggien-06-Foto-V1.jpg|200px]]
Projecting Loggias
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z19.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z14.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_Z19.png|200px]]
[http://quality.citygmlwiki.org/images/f/f6/Loggia-06-CityGML-LOD2_V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>
</table>
* In this example, the geometry is modeled within the <code>lod2Solid</code> but not within the specified <code>BoundarySurface</code> elements (opposed to the standard)!

-----
-----

==== Thoroughfare ====

===== Definition =====
SIG3D: An open '''Thoroughfare''' is a part of a building at ground level for '''vehicles''' to drive through the building. It is bounded by walls and a roof.

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">not recommended</span>'''



*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** Threshold LOD2 / LOD3:
*** Modeling only, if the Thoroughfare's depth and height >= 2 m;
** '''Modeling Principle''' (Thoroughfare in a building)
*** The building contains all geometry-containing boundary surfaces.
*** The Thoroughfare (BuildingInstallation) '''references (Xlink)''' to the building's corresponding boundary surfaces.
*** The building's volume references (Xlink) to the building's corresponding boarder surfaces.<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="600">[[image:Durchfahrt-Prinzip.png|600px]]</td></tr><tr align="center" valign="top"><td>Modeling Principle of a Thoroughfare</td></tr></table>
** '''Modeling Principle''' (Shared Thoroughfare through two buildings)
*** Each building contains all geometry-containing boundary surfaces
*** The Thoroughfare (BuildingInstallation) is assigned to the building which contains the greater part of the Thoroughfare. The Thoroughfare '''references (Xlink)''' to the building's corresponding boarder surfaces and complements the Thoroughfare with bounding geometry at the BuildingInstallation.
*** The building's volume references (Xlink) to the building's corresponding boarder surfaces.<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Durchfahrt-Prinzip-Var-2.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modeling Principle of a shared Thoroughfare</td>
</tr>
</table>

<br />
'''Note:''' The modeling of buildings with a closed building construction is described in [[#GebäudeInGeschlossenerBauweise|Kapitel 3.7]]

===== Attributes =====
;''bldg:function''
:Thoroughfare (1002); see SIG 3D codelist recommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> A Thoroughfare is considered as a building component which semantically consists of the building's boundary surfaces and possibly an exterior floor surface.

===== Examples =====
<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="left">
<td colspan="6">
'''Thoroughfares'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Actual Example
</td>
<td>
ALKIS
</td>
<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Durchfahrt_Z26.png|200px]]
Thoroughfare inside of a building
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z26.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z26.png|200px]]
[http://quality.citygmlwiki.org/images/0/05/Durchfahrt-01-CityGML-LOD1-V2.gml CityGML download]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-01-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/2/20/Durchfahrt-01-CityGML-LOD2-V2.gml CityGML download]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Zwei_Gebaeude_mit_gemeinsamer_Durchfahrt-02-Foto-V1.jpg|200px]]
Two buildings with a shared Thoroughfare
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z27.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z26.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-02-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/a/a5/Durchfahrt-02-CityGML-LOD2-V4.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

Two buildings with separate Thorouoghfares
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z28.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z27.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-03-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/f/f1/Durchfahrt-03-CityGML-LOD2-V2.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

Two offset buildings with separate Thoroughfares
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z29.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z29.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-04-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/4/4c/Durchfahrt-04-CityGML-LOD2-V1.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Zwei_Gebaeude_mit_einseitiger_Durchfahrt-05-Foto-V1.jpg|200px]]
Two buildings with onesided Thoroughfare
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z27.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-05-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/e/eb/Durchfahrt-05-CityGML-LOD2-V1.gml CityGML herunterladen]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Zwei_Gebaeude_mit_Verbindungstrakt-01-Foto-V1.jpg|200px]]
Two buildings with a connection section
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z31.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z31.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Durchfahrt_Z31.png|200px]]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Durchfahrt_Z53.png|200px]]
Upper floor Thoroughfare
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z53.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Durchfahrt_Z53.png|200px]]
</td>
<td width="200px" valign="bottom">
</td>
</tr>
</table>

==== Dormers / Zwerchhaus (Zwerchgiebel)====

===== Definition =====
'''SIG3D:'''
'''SIG3D:''' A '''dormer'''' is a structural element of a building that protrudes from the plane of a sloping roof surface. Dormers are used, either in original construction or as later additions, to create usable space in the roof of a building by adding headroom and usually also by enabling addition of windows [Wikipedia].

A '''dormer''' does not lie on the same plane as the building's exterior wall. The dormer (or the dormer's footprint) has a minimum offset of 0,5 m and lies inside the building's footprint.

'''SIG3D:''' The '''Zwerchhaus''' is a one or more story installation of a sloping roof surface. It consists of a gable and its own roof. The !!!Zwerchgiebel!!! follows the exterior wall's building line. That represents the difference between a !!!Zwerchhaus!!! and a gable, because a gable does not have to follow the building line. The roof of the !!!Zwerchhaus!!! is often designed as a ridge roof. The ridge follows cross to the main roof's ridge. So the rainwater pipes continue in an orthogonal way to each other.

'''Note:''' The '''zwerchhaus''' is not modeled as a part of the building installation, but as a building's boundary surface itself.

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">not recommended</span>'''

*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** Threshold LOD2:
*** Modeling only, if the dormer's height >= 2 m;
** Threshold LOD3:
***
** '''Modeling Principle'''
*** The building contains all geometry-containing boundary surfaces of the building structure. To close the building's volume, a ClosureSurface is modeled into the roof's gap.
*** The dormer (BuildingInstallation) '''contains all geometry-containing boundary surfaces''' of the dormer. To close the volume, either a ClosureSurface is modeled or it is closed by referencing to the building's corresponding ClosureSurface (Xlink to OrientableSurface).
*** The building's volume, the building structure's volume and the volume of the dormer ('''CompositeSolid''') reference (Xlink)to the corresponding boundary surfaces of the building structure and dormer.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Dachgaube-Prinzip.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modelling Principle of a dormer</td>
</tr>
</table>

===== Attributes =====
;''bldg:function''
:Dormer (1003); see SIG 3D codelisten recommendation for[http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> A dormer is considered as a building component which semantically consists of the building's boundary surfaces.

===== Examples =====
<table width="1200px" border="1" cellspacing="0" >

<tr align="left">
<td colspan="6">
'''Dormer'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Actual Example
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="top">

</td>

<td width="200px" valign="top">

</td>
<td width="200px" valign="top">

</td>
<td width="200px" valign="top">
[[image:DachgaubeClosure-01-LOD2.jpg|200px]]
[http://quality.citygmlwiki.org/images/b/b5/DachgaubeClosure-V1.gml CityGML download]
</td>
<td width="200px" valign="top">

</td>
</tr>
</table>

<table width="1200px" border="1" cellspacing="0" >

<tr align="left">
<td colspan="6">
'''Zwerchhaus (Zwerchgiebel)'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Actual Example
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="top">
[[image:Zwerchhaus-Foto-V3.jpg|200px]]
</td>

<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD0-v02.png|170px]]
[http://quality.citygmlwiki.org/images/a/a0/Zwerchgiebel-LOD0-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD1-v02.png|170px]]
[http://quality.citygmlwiki.org/images/3/32/Zwerchgiebel-LOD1-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD2-v02.png|170px]]
[http://quality.citygmlwiki.org/images/4/4b/Zwerchgiebel-LOD2-V02.gml CityGML download]
</td>
<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD3-v02.png|170px]]
[http://quality.citygmlwiki.org/images/d/d4/Zwerchgiebel-LOD3-V01.gml CityGML download]
</td>

</tr>
</table>

==== Arcades / Architrav ====

===== Definition =====
'''SIG3D:''' An arcade is a succession of arches, each counter thrusting the next, supported by columns or piers, or a covered walk enclosed by a line of such arches on one or both sides. In warmer or wet climates, exterior arcades provide shelter for pedestrians.[Wikipedia]

'''SIG3D:''' An '''architrave''' (from Italian architrave, from Greek ἀρχι, archi- and Latin trabs, bar) is the lintel or beam that rests on the capitals of the columns. It is an architectural element in Classical architecture. In the ancient world, it was also called Epistyl because it was commonly built on pillars.[Wikipedia]

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">net recommended</span>'''

*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** '''Threshold LOD2:'''
*** Threshold-values for the modelling of beams: all sides of the beam's BoundingBox are >= 0.5 m
** '''Modelling principle'''
*** The building contains all geometry-containing boundary surfaces
*** The Arcade (BuildingInstallation) '''references (Xlink)''' to the building's corresponding boundary surfaces
*** The building's volume references (Xlink) to the building's corresponding boundary surfaces

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Arkade-Prinzip.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modelling principle of an arcade</td>
</tr>
</table>

===== Attributes =====
;''bldg:function''
:Arcade (1009); see SIG 3D codelist recommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> An Arcade is considered as a building component which semantically consists of the building's boundary surfaces.

===== Examples =====

{| width="1200px" cellspacing="0" border="1" style="border:thin"
|- align="left"
| colspan="6" |
'''Arcades'''

|- valign="top" align="center"
|
Actual example

|
ALKIS

|
CityGML LOD0

|
CityGML LOD1

|
CityGML LOD2

|
CityGML LOD3

|- align="center"
| width="200px" valign="bottom" |
[[Image:Real Arkaden.png|200px]]

| width="200px" valign="bottom" |
[[Image:ALKIS Arkaden.png|200px]]

| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
[[Image:LOD1 Arkaden.png|200px]]

| width="200px" valign="bottom" |
[[Image:LOD2 Arkaden V1.png|200px]]

| width="200px" valign="bottom" |
|- align="center"
| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
[[Image:LOD2 Arkaden V2.png|200px]]

| width="200px" valign="bottom" |
|}

<br>

{| width="1200px" cellspacing="0" border="1"
|- align="left"
| colspan="6" |
'''Arcade'''

|- valign="top" align="center"
|
Real Building



|
CityGML LOD0

|
CityGML LOD1

|
CityGML LOD2

|
CityGML LOD3

|- align="center"
| width="200px" valign="top" |
[[Image:Arkaden-01-Foto-V1.jpg|200px]]



| width="200px" valign="top" |
[[Image:Arkade-LOD0-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/4/43/Arkade-LoD0-Beispiel-Wiki-01-V01.gml CityGML download]

| width="200px" valign="top" |
[[Image:Arkade-LOD1-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/2/21/Arkade-LoD1-Beispiel-Wiki-01-V01.gml CityGML download]

| width="200px" valign="top" |
[[Image:Arkade-LOD2-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/e/e5/Arkade-LoD2-Beispiel-Wiki-01-V01.gml CityGML download]

| width="200px" valign="top" |
[[Image:Arkade-LOD3-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/f/fb/Arkade-LoD3-Beispiel-Wiki-01-V01.gml CityGML download]

|}

-----
-----

Modeling Guide for 3D Objects - Part 2: Modeling of Buildings (LoD1, LoD2, LoD3)

2013-12-17T11:14:41Z

Egbert Casper: /* Geometry */

{{TOC limit|4}}
== Document History ==

<table border="1" cellspacing="0">
<tr align="left" valign="top">
<th width="220">
Version
</th>
<th width="220">
Datum
</th>
<th width="220">
Autor/en
</th>
<th width="220">
Status
</th>
<th width="220">
Bemerkungen
</th>
</tr>
<tr align="left" valign="top">
<td>
0.8.0
</td>
<td width="220">
Januar 2012
</td>
<td>
</td>
<td bgcolor="#ff7777">
nicht öffentlich
</td>
<td>
Erste Versuche
</td>
</tr>
<tr align="left" valign="top">
<td>
0.9.0
</td>
<td width="220">
April 2012
</td>
<td>
</td>
<td bgcolor="#ff7777">
nicht öffentlich
</td>
<td>
Fertigstellung von Kapitel 1-4.1; 4.2 wird später bearbeitet
</td>
</tr>
<tr align="left" valign="top">
<td>
1.0.0
</td>
<td width="220">
Mai 2012
</td>
<td>
SIG 3D / AG Qualität
</td>
<td bgcolor="#73ff73">
öffentlich
</td>
<td>
Erste öffentliche Version von Kapitel 1-4.1;
</td>
</tr>
<tr align="left" valign="top">
<td>
1.1.0
</td>
<td width="220">
Januar/Februar 2013
</td>
<td>
SIG 3D / AG Qualität
</td>
<td bgcolor="#ff7777">
nicht öffentlich
</td>

<td>
Vorbereitung Version 2.0.0 mit Erweiterter Modellierung;
</td>
</tr>
<tr align="left" valign="top">
<td>
2.0.0
</td>
<td width="220">
März 2013
</td>
<td>
SIG 3D / AG Qualität
(c) 2013 Copyright Special Interest Group 3D (SIG3D) of the Spatial Data Infrastructure Germany (GDI-DE) http://www.sig3d.org
</td>
<td bgcolor="#73ff73">
öffentlich
</td>

<td>
Erste öffentliche Version mit Erweiterter Modellierung;
</td>
</tr>
<tr align="left" valign="top">
<td>
2.0.0 EN
</td>
<td width="220">
November 2013
</td>
<td>
SIG 3D / Quality Working Group
(c) 2013 Copyright Special Interest Group 3D (SIG3D) of the Spatial Data Infrastructure Germany (GDI-DE) http://www.sig3d.org /EC, KHH
</td>
<td bgcolor="#73ff73">
public </td>

<td>
First English version;
</td>
</tr>

</table>
-----
-----

== Introduction ==

=== Scope ===
* The modeling recommendations are usually independent from the recording method that means that this document is '''not''' a recording manual.
* This document describes the modeling of 3D objects on the basis of '''existing information'''. In case of lacking information, in particular in case of missing height information, objects must '''explicitly not''' be modeled. For example, if all relevant information on balconies is available, this document provides recommendations for a standardized modeling. Otherwise balconies must not be modeled.
* Recommendations are related to the Open Geospatial Consortium (OGC) standard '''CityGML version 1.0 and 2.0'''.
* This document refers to '''national (German) and European standards''' (AdV, INSPIRE) and can only be partially generalized.
* This document is restricted to the '''outer shell''' of buildings, i.e. building modeling up to LoD3
-----
-----

=== Target Group===
* Modeler
* Data holder
* Developer
-----
-----

=== Prior Knowledge Required ===
* GML: Geography Markup Language
* CityGML: Application schema for GML for the representation, storage, and exchange of virtual 3D city and landscape models
* [[ALKIS]]: Official German Land Registry Information System
-----
-----

=== Further References ===
* [https://portal.opengeospatial.org/modules/admin/license_agreement.php?suppressHeaders=0&access_license_id=3&target=http://portal.opengeospatial.org/files/%3fartifact_id=28802 CityGML 1.0 Specification]

* [https://portal.opengeospatial.org/modules/admin/license_agreement.php?suppressHeaders=0&access_license_id=3&target=http://portal.opengeospatial.org/files/%3fartifact_id=47842 CityGML 2.0 Specification]

* [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)]]

* [http://www.adv-online.de/icc/extdeu/binarywriterservlet?imgUid=42b23fd2-1153-911a-3b21-718a438ad1b2&uBasVariant=11111111-1111-1111-1111-111111111111&isDownload=true GeoInfoDok V 6.0 - Modeling of the geoinformation of the official surveying and mapping of Germany (Main Document, in German only)]

* [http://www.adv-online.de/AAA-Modell/Dokumente-der-GeoInfoDok/binarywriterservlet?imgUid=c9e63fd2-1153-911a-3b21-718a438ad1b2&uBasVariant=11111111-1111-1111-1111-111111111111&isDownload=true ALKIS feature catalogue with building information ( in German only)]
-----
-----

=== Document Conventions ===
* '''Features''' are written in ''italic characters'' with the corresponding name space in ''' ''bold characters'' '''.
* '''Examples''' are written in <tt>fixed width</tt>.
* '''Online references''' to other internal or external pages and documents are written in <span style="color:blue;">blue</span>.
* A statement which is not valid for all '''Levels of Detail''' (LoD) is noted as (LoD[1234][+]), e.g. a notation with (LoD1) is only valid for LoD1, a notation (LoD2+) is valid for all LoDs from LoD2 and above.
-----
-----

== Definitions und Determinations ==

=== Level of Detail (Building, BuildingPart)===

'''Definitions of SIG 3D:'''
* LoD0
** For every building or building part the footprint or roof outline is representad by a horizontal polygon with a well defined absolute and constant height.
* LoD1
** For every building or building part the generalized outer shell is represented by exactly one prismatic extrusion solid. Ground, floor and roof surfaces must be horizontal, lateral boundary surfaces must be vertical.
* LoD2
** For every building or building part the geometrically simplified outer shell is represented by horizontal resp. vertical outer surfaces and simplified roof shapes. All kind of surfaces ( e.g. ground surfaces, wall surfaces, roof surfaces, outer ceiling surfaces, outer floor surfaces, virtual closure surfaces ) and additional building elements ( e.g. building installations like balkonies, dormers and chimneys ) may be represented as semantic objects.
* LoD3
** For every building or building part the geometrically detailed outer shell is represented by detailed outer surfaces and detailed roof shapes. All kind of surfaces ( e.g. ground surfaces, wall surfaces, roof surfaces, outer ceiling surfaces, outer floor surfaces, virtual closure surfaces ) and additional building elements ( e.g. building installations like balkonies, dormers and chimneys ) may be more detailly represented as semantic objects. In respect to LoD2 doors and windows can be modeled as planar thematic objects.
* LoD4
** For every building or building part the geometrically detailed outer shell and interior is represented by detailed outer and inner surfaces and detailed roof shapes. All kind of surfaces ( e.g. ground surfaces, inner and outer wall surfaces, inner and outer roof surfaces, outer ceiling surfaces, outer floor surfaces, virtual closure surfaces ) and additional movable and non movable building elements ( e.g. building installations like balkonies, dormers, chimneys, interior and furniture ) may be more detailly represented as semantic objects.
-----

=== Reference Coordinate System ===
CityGML 2.0 strongly recommends the specification of a reference coordinate system. For a meaningful use of data a valid reference coordinate system is imperative, therefore a valid reference coordinate system must be defined for each instance file:

* A reference coordinate system must be defined as '''three dimensional''' (usually position and height reference system --> [[Definitionen#CCRS|see Compound Coordinate Reference System]]).
* A reference coordinate system should '''not''' be changed within an instance file.
* A reference coordinate system should be defined once within <tt><gml:Envelope></tt>.

'''Recommendations for Germany:''' ''ETRS89 / UTM / Reference ellipsoid GRS80 + DHHN92''

'''CityGML Example:'''

<tt>
<gml:boundedBy>
<gml:Envelope srsDimension="3" srsName="'''urn:adv:crs:ETRS89_UTM32*DE_DHHN92_NH'''">
'''--> [[Definitionen#CCRS|see Compound Coordinate Reference System]]'''
<gml:lowerCorner srsDimension="3">458868.0 5438343.0 112.0 </gml:lowerCorner>
<gml:upperCorner srsDimension="3">458892.0 5438362.0 117.0 </gml:upperCorner>
</gml:Envelope>
</gml:boundedBy>
</tt>

'''ALKIS Example:'''

<tt>
<gml:boundedBy>
<gml:Envelope srsName="'''urn:adv:crs:ETRS89_UTM32'''">
<gml:pos>367456.554 5718128.391</gml:pos>
<gml:pos>367505.094 5718091.143</gml:pos>
</gml:Envelope>
</gml:boundedBy>
</tt>

see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#Spatial-Reference-System|Modeling Guide for 3D Objects - Part 1]]
-----
-----

=== <span id="ModelStructure">Model Structure</span> ===

The use of ''core:CityModel'' is not explicitely regulated in the specification and in the schema. The multiple use of ''core:CityModel'' is compliant to the schema and will be validated.
In order to avoid conflicts while importing CityGML models, it is recommended to use '''exactly one''' instance of ''core:CityModel'' as '''root element'''.

-----
-----

=== <span id="Heights">Heights</span> ===
The ''measuredHeight'' is the '''measured''' or '''computed''' difference between the lowest terrain intersection point and the highest roof point with the following properties:

* the ''measuredHeight'' is a '''simple''' attribute can not further specified and/or qualified;
* the ''measuredHeight'' is '''always''' related to the '''real''' building;
* the ''measuredHeight'' is '''independent of the LoD''' of the building;
* the '''computation''' of the ''measuredHeight'' should always base on the terrain model with the '''highest available resolution'''.

The following heights are valid for flat roofs, outshot roofs, gable roofs, hip roofs, jerkinhead roofs, mansard roofs, pyramid roof, shed roof, shells and domes:

[[image:Höhenangaben-01.png|800px]]

The following heights are valid for all kind of shed roofs:

[[image:Höhenangaben-02.png|800px]]

The following heights are valid for different roof overhangs:

[[image:Höhenangaben-03.png|800px]]

If you need absolute heights for the noted values you must define them as generic attributes (dimensioned ''gen:measureAttribute''):
* ''<gen:measureAttribute name="min height surface"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
* ''<gen:measureAttribute name="min height eaves"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
* ''<gen:measureAttribute name="max height eaves"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
* ''<gen:measureAttribute name="max height ridge"><gen:value uom="#m">Value</gen:value></gen:measureAttribute>''
-----
-----

=== <span id="TerrainIntersectionLine">Terrain Intersection Line</span> ===
In CityGML the terrain intersection line is an attribute of a building or building part. It is generated by intersection of the building or building part with the terrain and has the following properties:

* a terrain intersection line can be '''measured''' or '''calculated''' ;
* if a terrain intersection line is calculated, the terrain model with the '''highest resolution available''' should be used;
* a terrain intersection line is an '''attribute''' of the '''building or building part''';
* outer building installations (''bldg:BuildingInstallation'') are '''taken into account''' from a terrain intersection line (see '''Figure A''');
* a terrain intersection line is a result of the intersection of buildings in the respective LoD and the most accurate available terrain. In CityGML it has no relation to the terrain used in a visualization and its resolution and accuracy.
* a terrain intersection line may consist of '''several independent parts''';
* a terrain intersection line '''need not be closed''';
* a terrain intersection line which does not exist in reality will '''not be taken into account''' (e.g. in the case of building parts ).
<table width="800px" border="0" cellspacing="6">
<tr align="middle">
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall a.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall b.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall c.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:TerrainIntersection-Fall d.png|200px]]
</td>
<tr align="middle" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
<td>
Figure C
</td>
<td>
Figure D
</td>
</tr>

</table>
-----
-----

=== <span id="AuskragendeBauelemente">Cantilevered Building Elements</span> ===
Cantilevered or projecting building elements are defined as '''parts''' of roofs, walls etc, which should '''not be considered in the volume calculation of the building'''. Cantilevered or projecting building elements are modeled as follows:
* as surface element(s) always separated from the volume-forming building element (see '''Figure A''')
* always as a surface element, if the thickness of the building element is less than 0.5 m (see '''Figure B''')
* always as a solid element, if the thickness of the building element is greater than 0.5 m (see '''Figure B''')
* in LoD2 always as a surface element, if the thickness of the building element is less than 0.5 m
* in LoD2 always as a solid element, if the thickness of the building element is greater than 0.5 m
* in LoD3 always in the best accuracy based on available information.


<table border="0" cellspacing="0">
<tr align="left" valign="center">
<td width="800">
[[image:AuskragendeBauelemente-1.png|800px]]
</td>
</tr>
<tr align="middle" valign="top">
<td width="500">
Figure A
</td>
</tr>
</table>

<table border="0" cellspacing="0">
<tr align="middle" valign="top">
<td width="500">
[[image:AuskragendeBauelemente-2.png|500px]]
</td>
</tr>
<tr align="middle" valign="top">
<td>
Figure B
</td>
</tr>
</table>

-----
-----

=== <span id="ClosedCoverageType"> Closed Coverage Type</span> ===
Buildings as parts of closed coverage type (applies to semi-detached and terrace houses also) can be modeled as follows:
* Buildings that are '''separated within the land register''' should be modeled as '''separate buildings'''.
<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="400">[[image:GeschlosseneBauweise-01-V01.png|400px]]</td><td width="400">[[image:GeschlosseneBauweise-04-V01.png|400px]]</td></tr><tr align="left" valign="center"><td width="400">Separate buildings of closed coverage type</td><td width="400">Terrace houses as separate buildings</td></tr></table>
* Buildings that are '''united within the land register''' should be modeled as '''one single building''' which can be subdivided into building parts (e.g. row of buildings, semi-detached or terrace houses).
<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="400">[[image:GeschlosseneBauweise-02-V01.png|400px]]</td><td width="400">[[image:GeschlosseneBauweise-03-V01.png|400px]]</td></tr><tr align="left" valign="center"><td width="400">Terrace houses as one single building</td><td width="400">Terrace houses as building parts</td></tr></table>
* Buildings '''without any land register information''' and for which the building detection provides '''no usable structures''' (e.g. based on flights) should be modeled as '''one single building'''.<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="400">[[image:GeschlosseneBauweise-02-V01.png|400px]]</td></tr><tr align="left" valign="center"><td width="400">Terrace houses as one single building</td></tr></table>

The modeling of '''boundary surfaces''' between buildings must satisfy the following geometric resp. semantic conditions:
* Common boundary surfaces may only '''be referenced within a building via Xlink''' (building-building part resp. building part - building part).

-----
-----

=== <span id="Addresses">Addresses</span> ===
* The CityGML specification allows to assign an address both to a building (''bldg:Building'', ''bldg:BuildingPart'') as well to a door (''bldg:Door''). It is recommended '''always to assign an address to a building''' (in any LoD) because doors are not available in LoD1 and LoD2.

* It is recommended to use the complete '''postal address'''.

* '''Multiple addresses''' can be assigned to one building.

* '''Umlauts''' are allowed in addresses (z.B. <span style="color:#008000">Würzburg☺</span>, <span style="color:#008000"> Wuerzburg☺</span>, <span style="color:#FF0000">Würzburg and Wuerzburg mixed ☹</span>).

'''General example:'''

Street: Hermann-von-Helmholtz-Platz
Number: 1
Zip Code: 76344
City: Eggenstein-Leopoldshafen

'''CityGML example:'''

<core:Address>
<core:xalAddress>
<xAL:AddressDetails>
<xAL:Locality Type="Town">
<xAL:LocalityName>'''Eggenstein-Leopoldshafen'''</xAL:LocalityName>
<xAL:Thoroughfare Type="Street">
<xAL:ThoroughfareNumber>'''1'''</xAL:ThoroughfareNumber>
<xAL:ThoroughfareName>'''Hermann-von-Helmholtz-Platz'''</xAL:ThoroughfareName>
</xAL:Thoroughfare>
<xAL:PostalCode>
<xAL:PostalCodeNumber>'''76344'''</xAL:PostalCodeNumber>
</xAL:PostalCode>
</xAL:Locality>
</xAL:AddressDetails>
</core:xalAddress>
</core:Address>
-----
-----

=== Codelists ===
Codelists for the CityGML 2.0 standard are available at "http://www.sig3d.org/codelists/standard".

The recommendations for codelists in this modeling guide refer to the proposal of the SIG3D. These codelists are availabe (in German only) at "http://www.sig3d.org/codelists/Handbuch-SIG3D" and relate to ALKIS.

This modeling guide refers to the following codelists:

*Building resp. building part (''bldg:Building / bldg:BuildingPart'')
**class http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_class.xml
**function http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_function.xml
**usage http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_usage.xml
**roofType http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/_AbstractBuilding_roofType.xml

*Building installations (''bldg:BuildingInstallation'')
**function http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml

-----
-----

=== Generic Attributes ===
Generic (user defined) attributes may be used to represent attributes which are '''not covered explicitly by the CityGML schema'''. Generic attributes must be used with care; they shall only be used if there is no appropriate attribute available in the overall CityGML schema. Otherwise, problems concerning semantic interoperability may arise. Interoperability of generic attributes is '''reduced to attribute values''' which can only be interpreted semantically by additional information.
The following attribute types are defined:

* ''stringAttribute'' - for arbitrary strings
* ''intAttribute'' - for dimensionless integer numbers
* ''doubleAttribute'' - for dimensionless floating point numbers
* ''dateAttribute'' - for dates with integer-valued year, month and day representation in the format YYYY-MM-DD (e.g. 2013-03-08)
* ''uriAttribute'' - represents a Uniform Resource Identifier Reference (URI) (e.g. a link to a document or a web site)
* ''measureAttribute'' - for dimensioned values (CityGML 2.0)

Attributes can be combined in CityGML 2.0 by generic attribute sets '''''genericAttributeSet''''' with an optional '''''codeSpace'''''. If the '''''codeSpace''''' attribute is present, then its value should identify an authority for the set, such as the organisation or community who defined its content. The generic attribute set may contain arbitrary generic attributes.

'''CityGML Examples'''

<gen:stringAttribute name="'''construction'''"><gen:value>'''concrete'''</gen:value></gen:stringAttribute>
<gen:intAttribute name="'''entries'''"><gen:value>'''3'''</gen:value></gen:intAttribute>
<gen:doubleAttribute name="'''floor area ratio FAR'''"><gen:value>'''0.33'''</gen:value></gen:doubleAttribute>
<gen:dateAttribute name="'''approval date'''"><gen:value>'''2012-03-09'''</gen:value></gen:dateAttribute>
<gen:uriAttribute name="'''website '''"><gen:value>'''http://www.sig3d.org'''</gen:value></gen:uriAttribute>
<gen:measureAttribute name="'''building width'''"><gen:value uom="#'''m'''">'''10.00'''</gen:value>/gen:measureAttribute>

<gen:genericAttributeSet name="'''Base Quantities'''">
<gen:measureAttribute name="Height"><gen:value uom="#m">9.00</gen:value></gen:measureAttribute>
<gen:measureAttribute name="Area"><gen:value uom="#m2">80.00</gen:value></gen:measureAttribute>
<gen:measureAttribute name="Volume"><gen:value uom="#m3">720.00</gen:value></gen:measureAttribute>
</gen:genericAttributeSet>
-----
-----

=== Geometry ===

There is '''no GML Profile''' for CityGML. This means that CityGML instance files will validate with every GML geometry. The specification '''restricts''' the usage of GML geometry classes (CityGML 2.0 Annex D "Overview of employed GML3 geometry classes).
CityGML references to the following geometry classes ('''CityGML 2.0 Annex D'''):

<table width="1200px" border="1" cellspacing="0">
<tr align="left">
<td width="250px">
'''Abstract Classes'''
</td>
<td width="250px">
'''Instantiated Classes'''
</td>
<td width="700px">
'''Further Limitations'''
</td>
</tr>
<tr>
<td width="250px" rowspan="2">
''gml:_Solid''
</td>
<td width="250px">
''gml:'''Solid'''''
</td>
<td>
only ''gml:OrientableSurface'', ''gml:Polygon'', ''gml:CompositeSurface'',

''tex:TexturedSurface'' (obsolete)
</td>
</tr>
<tr>
<td>
''gml:'''CompositeSolid'''''
</td>
<td>
no restriction
</td>
</tr>

<tr>
<td rowspan="6">
''gml:_Surface''
</td>
<td>
''gml:'''Polygon'''''
</td>
<td>
only ''gml:'''LinearRing''''' and ''gml:'''Ring''''' exclusively with ''gml:LineString'' or ''gml:CompositeCurve''
</td>
</tr>
<tr>

<td>
''gml:'''OrientableSurface'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>

<td>
''tex:TextureSurface''
</td>
<td>
obsolete
</td>
</tr>
<tr>

<td>
''gml:'''CompositeSurface'''''
</td>
<td>
only ''gml:OrientableSurface'', ''gml:Polygon'', ''gml:CompositeSurface''

''tex:TexturedSurface'' (veraltet)
</td>
</tr>
<tr>

<td>
''gml:'''TriangulatedSurface'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>

<td>
''gml:'''Tin'''''
</td>
<td>
no restriction
</td>
</tr>

<tr>
<td rowspan="2">
''gml:_Curve''
</td>
<td>
''gml:'''LineString'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>
<td>
''gml:'''CompositeCurve'''''
</td>
<td>
''gml:LineString'' and ''gml:CompositeCurve'' only
</td>
</tr>
<tr>
<td>
''gml:_GeometricPrimitive''
</td>
<td>
''gml:'''Point'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>

<td>
''gml:_Coverage''
</td>
<td>
''gml:'''RectifiedGridCoverage'''''
</td>
<td>
no restriction
</td>
</tr>


<tr>
<td rowspan="6">
''gml:_AbstractGeometricAggregate''
</td>
<td>
''gml:'''MultiSolid'''''
</td>
<td>
no restriction
</td>

</tr>
<tr>
<td>
''gml:'''MultiSurface'''''
</td>
<td>
only ''gml:OrientableSurface'', ''gml:Polygon'', ''gml:CompositeSurface'',

''tex:TexturedSurface'' (obsolete)
</td>
</tr>
<tr>
<td>
''gml:'''MultiCurve'''''
</td>
<td>
only ''gml:LineString'' and ''gml:CompositeCurve''
</td>
</tr>
<tr>
<td>
''gml:'''MultiPoint'''''
</td>
<td>
no restriction
</td>
</tr>
<tr>
<td>
''gml:'''GeometricComplex'''''
</td>
<td>
restricted to connected linear networks
</td>
</tr>
<tr>
<td>
''gml:'''MultiGeometry'''''
</td>
<td>
restrictrions see allowed geometry types
</td>

</tr>

</table>

In order to keep the instance files small and to ensure an optimal editability of models, maximum flat polygons should be used, if appropriate with holes (inner rings).

-----
-----

=== File Name ===
It is recommended to use *.gml as file extension to distinguish CityGML files from other XML files.
-----
-----

== Modeling ==

=== Base Modeling ===
The base modeling includes the modeling of the '''building resp. building part''' itself in LoD1, with appropriate '''boundary surfaces''' in LoD2 and LoD3 and with '''windows and doors''' in LoD3. In addition, the basic modeling covers the general use of '''building installations'''.
-----
-----
==== <span id="Building">Building (''bldg:Building'')</span> ====

===== Definition =====
'''SIG3D:''' A free-standing self-supporting construction that is roofed, usually walled, and can be entered by humans and is normally designed to stand permanently in one place. It is intended for human occupancy (for example: a place of work or recreation), habitation and/or shelter of humans, animals or things.

'''ISO:''' Provision of shelter for its occupants or contents as one of its main purposes; usually partially or totally enclosed and designed to stand permanently in one place

===== CityGML Feature =====
''bldg:Building''

===== Geometry =====
'''''gml:Solid''''' see [[Handbuch für die Modellierung von 3D Objekten - Teil 1: Grundlagen (Regeln für valide GML Geometrie-Elemente in CityGML)#gml:Solid| Modeling Guide - Part 1]]

It is recommended to use '''''gml:Solid''''' depending on the LoD in the following way :

*In LoD1 a solid directly contains the bounding geometry ('''Figure A''')
*In LoD2 and LoD3 a solid contains external references (Xlinks) to the bounding geometry ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer bottom surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]] as well as [[#Türen|doors]] and [[#Fenster|windows]]) ('''Figure B''') ( see also conformance requirement no. 4 in chapter 10.3.9 of the CityGML V2.0 specification )


<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="400">
[[image:BuildingSolid-V1.png|300px]]
</td>
<td width="400">
[[image:BuildingSolidXlink.png|350px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
</tr>
</table>

'''''gml:MultiSurface''''' ''' <span style="color:#FF0000">(not recommended)</span>'''

'''''gml:MultiCurve''''' '''<span style="color:#FF0000">(not recommended)</span>'''

===== <span id="BuildingAttributes">Attributes</span> =====
; ''gml:id'' <span style="color:#008000">(mandatory)</span>
: from GML version 3.2 onwards an id is mandatory
; ''gml:name'' <span style="color:#00FF00">(recommended, if available in the underlying land register)</span>
:'name' is the proper name or the name of the building.
; ''bldg:class'' (LoD1, LoD2, LoD3)
:The attribute ''bldg:class'' allows an unspecified classification of the building; no suggestion from the SIG3D;
; ''bldg:function'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:The 'function' of a building is the predominantly functional significance of the building at the date of data collection ( principle of dominance ); see also in the SIG3D code lists.
; ''bldg:usage'' (LoD1, LoD2, LoD3) <span style="color:#0000FF">(conditionally recommended)</span>
:The 'usage' of a building describes the use of the building and contains the respective percentage usage share of the total use.
; ''bldg:yearOfConstruction'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:The 'yearOfConstruction' is the year of completion of the construction or alteration of the building;
; ''bldg:yearOfDemolition'' (LoD1, LoD2, LoD3)
:The 'yearOfDemolition' is the year of deconstruction of the building;
;''bldg:roofType'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:'Roof type' describes the characteristic shape of the roof; see also in the code list of the SIG3D
; ''bldg:measuredHeight'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:'Measured height' is the difference in [m] between the highest point of the roof structure and the defined footprint of the building; see also [[#Heights|Heights]]
; ''bldg:storeysAboveGround'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended, if available in the underlying land register)</span>
:'storeys above ground' is the number of above-ground floors
; ''bldg:storeysBelowGround'' (LoD1, LoD2, LoD3) <span style="color:#00FF00">(recommended, if available in the underlying land register)</span>
:'storeys below ground' is the number of underground floors
; ''bldg:storeysHeightsAboveGround'' (LoD1, LoD2, LoD3)
:Height between two consecutive floors of the above-ground floors
; ''bldg:storeysHeightsBelowGround'' (LoD1, LoD2, LoD3)
:Height between two consecutive floors of the underground floors
; ''bldg:lodXSolid'' (LoD1, LoD2, LoD3)
:LoDX geometry (volume)of the building
; ''bldg:lodXMultiSurface'' (LoD1, LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:LoDX geometry (surface) of the building
; ''bldg:lodYMultiCurve'' (LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:LoDY geometry (curve) of the building
; ''bldg:lodXTerrainIntersection'' (LoD1, LoD2, LoD3)
:LoDX geometry (curve) of the [[#Terrain Intersection Line|terrain intersection line]] of the building
; ''bldg:outerBuildingInstallation'' (LoD2, LoD3)
:Relation to LoD2/LoD3 building installation
; ''bldg:boundedBy'' (LoD2, LoD3)
: Relation to boundary surfaces ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer floor surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]])
; ''bldg:consistsOfBuildingPart'' (LoD1, LoD2, LoD3)
:Relation to LoD1/LoD2/LoD3 building parts
; ''bldg:address'' (LoD1, LoD2, LoD3)
:Relation to one or more building addresses

===== Examples =====

<table width="1200px" border="0" cellspacing="6">
<tr align="left">
<td colspan="6">
'''Detached family house'''
</td>
</tr>
<tr align="middle">
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-real.png|200px]]
</td>

<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD0.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD1.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD2.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Building-Example-1-V1-LOD3.png|200px]]
</td>
<tr align="middle" valign="top">
<td>
Real Building
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

</table>
-----
-----

==== <span id="Gebäude">Building Part (''bldg:BuildingPart'')</span> ====

===== Definition =====
'''SIG3D:''' A building part is a sub-division of a building that is homogeneous related to its physical, functional or temporal aspects and may be considered as a building.

The subdivision of a building can be done by different criteria, e.g.
* structural like number of floors, roof type, height, construction method,
* administrative like building function, ownership, year of construction.

Building parts (''bldg:BuildingParts'') must satisfy the following conditions ( necessary conditions ):
* A building part '''always''' has a relation (bldg:consistsOfBuildingPart) to '''exactly one''' building:
* Buildings and building parts '''touch each other''' planar or linear-shaped,
* Building parts must be '''"connected to ground"''' and can have the following '''properties''' ( for example, storeys are no building parts ):
** Building parts may have different '''building attributes''' ( e.g. function, roof type ),
** Building parts may have an address that '''differs''' from the address of the building,
** The geometry of building parts (''bldg:BuildingParts'') must be modeled in a way that both the '''volume''' and the '''surfaces''' of the boundary surfaces ( wall surfaces, roof surfaces and ground surfaces ) correspond to the real conditions ([[#BuildingPart/Geometry|see chapter Building Part/Geometry]]),
** If a building part is emphasized as the '''main part of the building''', its semantics and geometry can be modeled in the parent building,
** Building parts will not be subdivided into further building parts.

===== CityGML Feature =====

''bldg:BuildingPart''

===== <span id="BuildingPart/Geometry"> Geometry</span> =====
;'''''gml:Solid'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:Solid|Modeling Guide for 3D Objects - Part 1]]

:It is recommended to use '''''gml:Solid''''' depending on the LoD in the following way :

:*In LoD1 a solid directly contains the bounding geometry ('''Figure A''')
:*In LoD2 and LoD3 a solid contains external references (Xlinks) to the bounding geometry ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer bottom surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]] as well as [[#Türen|doors]] and [[#Fenster|windows]]). '''In real nonexistent surfaces''' are modeled as closure surfaces ('''Figure B''').
:*In LoD2 a solid contains external references (Xlinks) to the real bounding geometry. '''In real nonexistent surfaces''' are modeled as closure surfaces and assigned directly to the building part ('''Figure C''').


<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD1.png|200px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-FallB.png|200px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-FallB.png|200px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD1-gedreht.png|300px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-gedreht-FallB.png|300px]]
</td>
<td width="400">
[[image:Geometrie-Beispiel-Wiki-LOD2-gedreht-FallC.png|300px]]
</td>
</tr>

<tr align="left" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
<td>
Figure C
</td>

</tr>
</table>

; ''bldg:boundedBy'' (LoD2, LoD3)
: Relation to boundary surfaces ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer floor surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]])

'''''gml:MultiSurface''''' ''' <span style="color:#FF0000">(not recommended)</span>'''

'''''gml:MultiCurve''''' '''<span style="color:#FF0000">(not recommended)</span>'''

===== <span id="BuildingAttribute">Attributes</span> =====
Since the building part is derived from the building, all attributes of the building are also available for the building part (see also [[#BuildingAttribute|Building Attribute]]).

'''Exception:''' ''bldg:consistsOfBuildingPart''

===== Examples =====
<table width="1100px" border="0" cellspacing="0">
<tr align="left">
<td>
'''Office with factory hall'''
</td>
<td>

</td>
</tr>
<tr align="left">
<td width="550px" valign="bottom">
[[image:Buero-Werkshalle-01.png|500px]]
</td>
<td width="550px" valign="bottom">

</td>

</tr>
<tr align="left">
<td>
"structurally distinct" building parts → "Office" as function of BuildingPart 1 ; "Factory Hall" as function of BuildingPart 2
</td>
<td>

</td>
</tr>
</table>

<table width="1100px" border="0" cellspacing="0">
<tr align="left">
<td>
'''Detached house with staggered shed roof'''
</td>
<td>
'''House with a projecting floor'''
</td>
</tr>
<tr align="left">
<td width="550px" valign="bottom">
[[image:FJK-Haus-BuildingParts.png|500px]]
</td>
<td width="550px" valign="bottom">
[[image:FJK-Haus-BuildingParts-03.png|500px]]
</td>

</tr>
<tr align="left">
<td>
No "structurally distinct" building parts → roofType "staggered shed roof"
</td>
<td>
No "structurally distinct" building parts; 1 building part not "connected to ground"
</td>
</tr>
</table>

'''Examples with overarching building parts'''

Variante 1
[[image:Variante-01-V2-red.png|500px]]

'''Variante 2'''
[[image:Variante-02-V1-red.png|500px]]

Variante 3
[[image:Variante-03-V2-red.png|500px]]

-----
-----

==== <span id="BuildingInstallation">Building Installations (''bldg:BuildingInstallation'')</span> ====

===== Definition =====
'''SIG3D:''' Permanently installed parts of the buildings outer shell which are accessory for the building structure including loggia, dormer, etc. Doors and windows are modeled by the corresponding CityGML classes.

===== CityGML Feature =====

*'''LOD1:''' not available
*'''LOD2:''' ''bldg:BuildingInstallation''
*'''LOD3:''' ''bldg:BuildingInstallation''

===== <span id="BuildingInstallation/Geometry"> Geometry</span> =====
;'''''gml:Geometry'''''
:'''''gml:Geometry''''' allows '''points''', '''lines''', '''areas''', '''volumes''' as well as any combination of these elements.
:The use of points is '''<span style="color:#FF0000">not recommended</span>'''. <br />
:The use of lines is only '''<span style="color:#0000FF">recommenced under certain circumstances</span>''', because not all applications are able process this geometry.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:Haus-mit-Antenne-V1.png|300px]]
</td>
<td width="300">
[[image:Haus-mit-SolarPanel-V1.png|300px]]
</td>
<td width="300">
[[image:Haus-mit-Kamin-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
Lines (e.g. Antenna)
</td>
<td width="300">
Surfaces (e.g. Solar Panel)
</td>
<td width="300">
Volumes (e.g. Chimney)
</td>
</tr>
</table>

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:Haus-mit-SatellitenAntenne-V2.png|300px]]
</td>
<td width="300">
[[image:LoD2-Haus-Treppe-V2-MultiGeo-V1.png|300px]]
</td>
<td width="300">
[[image:Haus-mit-Balkon-V2.png|300px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
Lines and surfaces (e.g. satellite dish)
</td>
<td width="300">
Lines and surfaces resp. surfaces and volumes (e.g. stair and porch)
</td>
<td width="300">
Lines, surfaces und volumes (e.g. balcony)
</td>
</tr>
</table>

; ''bldg:boundedBy'' (LoD2, LoD3)
: Relation to boundary surfaces ([[#Wandflächen|wall surfaces]], [[#Dachflächen|roof surfaces]], [[#Grundflächen|ground surfaces]], [[#Äußere_Deckenflächen|outer ceiling surfaces]], [[#Äußere_Bodenflächen|outer floor surfaces]] and [[#Virtuelle_Begrenzungsflächen|closure surfaces]]) → see also [[#ErweiterteModellierung|Extended Modeling]]

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-Solid-V1.png|200px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-V1.png|320px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-Solid-V1-explode.png|200px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-V1-explode.png|320px]]
</td>
</tr>

<tr align="left" valign="center">
<td width="300">
Building with a small ridge turret (modeled as building installation with geometry)
</td>
<td width="500">
Building with a tower (modeled as building installation with boundary surfaces)
</td>
</tr>
</table>

===== <span id="BuildingInstallation/Attributes">Attributes</span> =====
; ''gml:id'' <span style="color:#008000">(mandatory)</span>
: from GML version 3.2 onwards an id is mandatory
; ''bldg:class'' (LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:The attribute ''bldg:class'' allows an unspecified classification of the building installation; no suggestion from the SIG3D;
; ''bldg:function'' (LoD2, LoD3) <span style="color:#00FF00">(recommended)</span>
:The 'function' of a building installation is the predominantly functional significance of the building installation at the date of data collection ( principle of dominance ); see also in the SIG3D code lists.
; ''bldg:usage'' (LoD2, LoD3) <span style="color:#FF0000">(not recommended)</span>
:no suggestion from the SIG3D;
; ''bldg:lodXGeometry'' (LoD2, LoD3)
:LoDX geometry of the building installation;

===== <span id="BuildingInstallation/Examples">Examples</span> =====
<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-Solid-LOD1-V1.png|300px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-Solid-LOD2-V1.png|300px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-Solid-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
LoD1: no building installation
</td>
<td width="300">
LoD2: simplified building installation
</td>
<td width="300">
LoD3: detailed building installation
</td>
</tr>
</table>
<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-LOD1-V1.png|400px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-V1.png|400px]]
</td>
<td width="300">
[[image:LoD2-Haus-Turm-BoundeBy-LOD3-V1.png|400px]]
</td>
</tr>
<tr align="left" valign="center">
<td width="300">
LoD1: no building installation
</td>
<td width="300">
LoD2: simplified building installation
</td>
<td width="300">
LoD3: detailed building installation
</td>
</tr>
</table>

------
------

==== <span id="GroundSurfaces">Ground Surfaces (''bldg:GroundSurface'')</span> ====

===== Definition =====
'''SIG3D:''' Exterior, lower boundary surface of a building, building part or building installation against soil or water ( e.g. foundation ).

===== CityGML Feature =====

*'''LoD1:''' not available
*'''LoD2:''' ''bldg:GroundSurface''
*'''LoD3:''' ''bldg:GroundSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:Solid|Modeling Guide for 3D Objects - Part 1]]
* A '''ground surface''' consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.

[[image:GroundSurface-Flaech-Volumen.png|600px]]

* The '''elevation''' of the ground surface depends on the availability of data:
** If there is information available about cellars, the elevation of the ground surface is set to the lower edge of the floor of the cellar ('''Figure A''');
** If the ground surface of the building, building part or building installation is generated by an intersection with the terrain, the elevation of the (horizontal) ground surface is set to the lowest absolute height of the corresponding terrain intersection line ('''Figure B''');
** It is <span style="color:#FF0000">not recommeded</span> to generate the ground surface of the building, building part or building installation directly from an intersection with the terrain ('''Figure C''');


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:GroundSurface-Skizze-5-V2.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-Skizze-6-V2.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-Skizze-7-V2.png|250px]]
</td>
<tr align="left" valign="top">
<td>
Figure A
</td>
<td>
Figure B
</td>
<td>
Figure C
</td>
</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>

===== Attribute =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry of the base area
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry of the base area
;''bldg:opening'' <span style="color:#FF0000">not recommended</span>
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:GroundSurface-0-V1.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-1-V1.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-2-V1.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-3-V1.png|250px]]
</td>
<tr align="left" valign="top">
<td>
Building without cellar and one floor slab
(One bldg:GroundSurface)
</td>
<td>
Building with cellar and one floor slab
(One bldg:GroundSurface)
</td>
<td>
Building with partial cellar and two different floor slabs
(Two bldg:GroundSurface)
</td>
<td>
Building with cellar and ramp
(Two bldg:GroundSurface)
</td>
</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:GroundSurface-5-V2.png|250px]]
</td>
<td width="253">
[[image:GroundSurface-6-V2.png|250px]]
</td>
<td width="250">
[[image:GroundSurface-7-V2.png|250px]]
</td>
<tr align="left" valign="top">
<td>
Building with ground surface at lower edge of floor cellar
(One bldg:GroundSurface)
</td>
<td>
Building with ground surface at lowest absolute height of the corresponding terrain intersection line
(One bldg:GroundSurface)
</td>
<td>
Building with ground surface based on intersection with the terrain
(One bldg:GroundSurface) <span style="color:#FF0000">not recommended</span>

</td>

</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>
-----
-----

==== <span id="WallSurfaces">Wall Surfaces (''bldg:WallSurface'')</span> ====

===== Definition =====
'''SIG3D:''' A wall surface is an exterior, lateral boundary surface of a building, building part or building installation.

'''ISO:''' A wall is a vertical construction that bounds or subdivides a space and usually fulfils a loadbearing or retaining function.

The normals of the wall surfaces should generally lie in the horizontal ( up to 45 degrees ).

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:WallSurface''
* '''LoD3:''' ''bldg:WallSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* A '''wall surface''' surface consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.

[[image:WallSurface-Flaechen-Volumen.png|600px]]

* '''Wall projections''', which do not limit the volume of the building will be modeled according to the rules for
'''[[#AuskragendeBauelemente|Cantilevered building elements]]'''.



* A '''wall surface''' ''must'' consist of '''several surfaces ( SurfaceMember )''' if :
** a wall surfaces has different '''colors''' or '''textures'''<table border="0" cellspacing="6"><tr align="left" valign="top"><td width="300">[[image:WallSurface-mit-Farben-V1.png|300px]]</td><td width="300">[[image:WallSurface-mit-Texturen-V1.png|300px]]</td><tr align="left" valign="top"><td>4 wall surfaces with 3 areas each (1 area in "orange"; 2 areas in "beige")(4 bldg:WallSurface)</td><td>4 wall surfaces with 2 areas each (1 area with texture "plaster"; 1 area with texture "sandstone") (4 bldg:WallSurface)</td></table>
** a wall surface is '''nonplanar'''<table border="0" cellspacing="6"><tr align="left" valign="top"><td width="300">[[image:WallSurface-Rund-V1.png|300px]]</td><td width="300">[[image:WallSurface-Laibungen-V1.png|300px]]</td><tr align="left" valign="top"><td>5 wall surfaces; 4 wall surfaces with 1 surface each and 1 wall surface (circular wall) with 6 surfaces (4 bldg:WallSurface)</td><td>Front wall as 1 wall surface consisting of 4 surfaces (revealing areas); right wall as 1 wall surface consisting of 13 surfaces (12 revealing areas)</td></table>
* A '''wall surface''' ''might'' consist of '''several surfaces ( SurfaceMember )''' if :
** it is intended to indicate a '''storey structure'''<table border="0" cellspacing="6"><tr align="left" valign="top"><td width="300">[[image:WallSurface-ohne-Stockwerke-V1.png|300px]]</td><td width="300">[[image:WallSurface-mit-Stockwerke-V1.png|300px]]</td><tr align="left" valign="top"><td>4 wall surfaces with 1 surface each (4 bldg:WallSurface)</td><td>4 wall surfaces with 3 surfaces each (ground floor, upper floor and top floor) (4 bldg:WallSurface)</td></table>

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry of the wall
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry of the wall
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====
<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:WallSurface-0-V2.png|250px|link=WallSurface-0-Animation]]
</td>
<td width="250">
[[image:WallSurface-1-V2.png|250px|link=WallSurface-1-Animation]]
</td>
<td width="250">
[[image:WallSurface-2-V2.png|250px|link=WallSurface-2-Animation]]
</td>
<tr align="left" valign="top">
<td>
A wall surface with 4 surfaces
(1 bldg:WallSurface)
<span style="color:#FF0000">not recommended</span>
</td>
<td>
4 wall surfaces with 1 surface each
(4 bldg:WallSurface)
</td>
<td>
4 wall surfaces (3 planar walls with 1 surface each and 1 circular wall with 12 surfaces)
(4 bldg:WallSurface)
</td>
</tr>
</table>

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:WallSurface-3-V2.png|250px]]
</td>
<td width="250">
[[image:WallSurface-4-V2.png|250px]]
</td>
<tr align="left" valign="top">
<td>
1 wall surface with elliptic or circular layout
(1 bldg:WallSurface)
</td>
<td>
5 wall surfaces by staggered facades
(5 bldg:WallSurface)
</td>
</table>
-----
-----

==== <span id="RoofSurfaces">Roof Surfaces (''bldg:RoofSurface'')</span> ====

===== Definition =====
'''SIG3D:''' A roof surface is a exterior, upper boundary surface of a building, building part or building installation, whose primary function is to protect from the effects of weather.
'''ISO:''' A roof is a construction that encloses a building from above

The normals of a roof should generally lie in the vertical.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:RoofSurface''
* '''LoD3:''' ''bldg:RoofSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* A '''roof surface''' surface consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.

[[image:RoofSurface-Flaechen-Volumen.png|600px]]

* '''Roof projections''', which do not limit the volume of the building will be modeled according to the rules for '''[[#AuskragendeBauelemente|cantilevered building elements]]'''.

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry of the roof
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry of the roof
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Gable Roof'''
</td>
<td width="250">
'''Gable Roof'''
</td>
<td width="250">
'''Mixed Roof'''
</td>
<td width="250">
'''Tent Roof'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:RoofSurface-0-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-1-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-2-V1.png|220px]]
</td>
<td width="250">
[[image:RoofSurface-3-V1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 roof surface with 2 surfaces
(1 bldg:RoofSurface) <span style="color:#FF0000">not recommended</span>
</td>
<td>
2 roof surfaces with 1 surface each
(2 bldg:RoofSurface)
</td>
<td>
3 roof surfaces ( 2 planar roof surfaces with 1 surface each and 1 conical roof area with 12 surfaces )
(3 bldg:RoofSurface)
</td>
<td>
1 conical roof area with 24 surfaces
(1 bldg:RoofSurface)
</td>
</tr>
<tr align="left" valign="top">
<td>

</td>
<td>

</td>
</tr>
</table>


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Jerkinhead Roof'''
</td>
<td width="250">
'''Gambrel Roof'''
</td>
<td width="250">
'''Arch Roof'''
</td>
<td width="250">
'''Dome Roof'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:RoofSurface-4-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-5-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-6-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-8-V1.png|220px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
4 roof surfaces
(4 bldg:RoofSurface)
</td>
<td>
4 roof surfaces
(4 bldg:RoofSurface)
</td>
<td>
1 roof surface with 12 surfaces
(1 bldg:RoofSurface)
</td>
<td>
1 roof surface with 264 surfaces
(1 bldg:RoofSurface)
</td>
</tr>
</table>

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Shed Roof I'''
</td>
<td width="250">
'''Shed Roof II'''
</td>
<td width="250">

</td>
<td width="250">

</td>

</tr>
<tr align="left" valign="top">
<td width="250">
[[image:RoofSurface-9-V1.png|250px]]
</td>
<td width="250">
[[image:RoofSurface-10-V1.png|250px]]
</td>
<td width="250">

</td>
<td width="250">

</td>
</tr>
<tr align="left" valign="top">
<td>
5 roof surfaces
(5 bldg:RoofSurface)
</td>
<td>
10 roof surfaces
(10 bldg:RoofSurface)
</td>
<td>

</td>
<td>

</td>
</tr>
</table>
-----
-----

==== <span id="OuterFloorSurfaces">Outer Floor Surfaces(''bldg:OuterFloorSurface'')</span> ====

===== Definition =====
'''SIG3D:''' Exterior, upper boundary surface of a building, building part or building installation which is not a roof.

The normals of an outer floor surface should generally be vertical directed upwards.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:OuterFloorSurface''
* '''LoD3:''' ''bldg:OuterFloorSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* An outer floor surface consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="400">
[[image:OuterFloorSurface-Uebersicht.png|300px]]
</td>
<td width="600">
[[image:OuterFloorSurface-Flaechen-Volumen.png|600px]]
</td>
</table>

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Roof terrace'''
</td>
<td width="250">
'''Loggia'''
</td>
<td width="250">
'''Roof terrace'''
</td>
</tr>
<tr align="left" valign="top">
<td width="300">
[[image:OuterFloorSurface-01-V1.png|300px]]
</td>
<td width="300">
[[image:OuterFloorSurface-02-V1.png|300px]]
</td>
<td width="300">
[[image:OuterFloorSurface-03-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 OuterFloorSurface
</td>
<td>
1 OuterFloorSurface
</td>
<td>
1 OuterFloorSurface
</td>
</tr>
</table>

-----
-----

==== <span id="OuterCeilingSurface">Outer Ceiling Surface(''bldg:OuterCeilingSurface'')</span> ====

===== Definition =====
'''SIG3D:''' Exterior, lower boundary surface of a building, building part or building installation against air.

The normals of an outer ceiling surface should generally be vertical directed downwards.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:OuterCeilingSurface''
* '''LoD3:''' ''bldg:OuterCeilingSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* An '''outer ceiling surface''' consists only of surfaces which are '''visible from the outside''' of the building, building part or building installation.


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="400">
[[image:OuterFloorSurface-Uebersicht.png|300px]]
</td>
<td width="600">
[[image:OuterCeilingSurface-Flaechen-Volumen.png|600px]]
</td>
</table>

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:opening''
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Passage'''
</td>
<td width="250">
'''Loggia'''
</td>
<td width="250">
'''Cantilevered floor'''
</td>
</tr>
<tr align="left" valign="top">
<td width="300">
[[image:OuterCeilingSurface-02-V1.png|300px]]
</td>
<td width="300">
[[image:OuterCeilingSurface-01-V1.png|300px]]
</td>
<td width="300">
[[image:OuterCeilingSurface-03-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 OuterCeilingSurface
</td>
<td>
1 OuterCeilingSurface
</td>
<td>
1 OuterCeilingSurface
</td>
</tr>
</table>

-----
-----

==== <span id="VitualBoundarySurface">Virtual Boundary Surface (''bldg:ClosureSurface'')</span>====

===== Definition =====
'''SIG3D:''' Exterior or interior boundary surface providing virtual boundaries, typically used to seal holes in volumetric objects.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' ''bldg:ClosureSurface''
* '''LoD3:''' ''bldg:ClosureSurface''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]
* A '''closure surface''' consists only of virtual ( imaginary ) surfaces which are '''visible from the outside''' of the building, building part or building installation.

===== Attributes =====
;''bldg:lod2MultiSurface''
:points to the LoD2 surface geometry
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:opening'' <span style="color:#FF0000">not recommended</span>
:points to a CityGML feature ''bldg:Opening'' ( ''bldg:Door'' ( see [[#Doors|doors]] ) or ''bldg:Window'' ( see [[#windows|windows]] ) )

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Open barn'''
</td>
<td width="250">
'''Railway platform hall'''
</td>
<td width="250">
'''Parking garage'''
</td>
</tr>
<tr align="left" valign="top">
<td width="300">
[[image:ClosureSurface-01-V1.png|300px]]
</td>
<td width="300">
[[image:ClosureSurface-03-V1.png|300px]]
</td>
<td width="300">
[[image:ClosureSurface-02-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
1 ClosureSurface
</td>
<td>
2 ClosureSurface
</td>
<td>
28 ClosureSurface
</td>
</tr>
</table>

-----
-----

==== <span id="Doors">Doors (''bldg:Door'')</span> ====

===== Definition =====
'''ISO 6707-1:''' Construction for closing an opening intended primarily for access or egress or both.

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' not available
* '''LoD3:''' ''bldg:Door''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]

* A '''door''' consists only of surfaces which are either '''visible from the outside''' of the building, building part or building installation ( case A, B or C ) or consists of '''solids''' ( case D ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:TerrassenTuer-Detail-0.png|250px]]
</td>
<td width="250">
[[image:TerrassenTuer-Detail-0-Texture.png|250px]]
</td>
<td width="250">
[[image:TerrassenTuer-Detail-1-Flaeche.png|250px]]
</td>
<td width="250">
[[image:TerrassenTuer-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
[[image:TerrassenTuer-Schnitt-Detail-0.png|250px]]
</td>
<td>
[[image:TerrassenTuer-Schnitt-Detail-0-Texture.png|250px]]
</td>
<td>
[[image:TerrassenTuer-Schnitt-Detail-1-Flaeche.png|250px]]
</td>
<td>
[[image:TerrassenTuer-Schnitt-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Door as a simple surface)
</td>
<td>
'''Case B''' (Door as a textured surface)
</td>
<td>
'''Case C''' (Door modeled in detail with surfaces only visible from the outside)
</td>
<td>
'''Case D''' (Door as a solid)
</td>
</tr>
</table>

* In order to ensure a closed outer shell of the building, the doors should '''not''' be modeled '''in an opened state''' ( case A ) but '''in closed condition''' ( case B ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="500">
[[image:Tuer-offen-red-v1.png|500px]]
</td>
<td width="500">
[[image:Tuer-zu-red-v1.png|500px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Doors opened)
</td>
<td>
'''Case B''' (Doors closed)
</td>
</tr>
</table>

===== Attributes =====
;''bldg:lod3MultiSurface''
:points to the LoD3 surface geometry
;''bldg:address''
:points to the address of the door

===== Examples =====


<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Simple Doors'''
</td>
<td width="250">
'''Simple Doors with Embrasure'''
</td>
<td width="250">
'''Doors modeled in detail'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:Beispiel-Tueren-GanzEinfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Tueren-Einfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Tueren-Komplex-Red-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
Number of Polygons (Complete Model) = 19
</td>
<td>
Number of Polygons (Complete Model) = 128
</td>
<td>
Number of Polygons (Complete Model) = 3498
</td>
</tr>
</table>

----
----

==== <span id="Windows">Windows (''bldg:Window'')</span> ====

===== Definition =====
'''SIG3D:''' Construction for closing an opening in a wall or roof, primarily intended to admit light and / or provide ventilation (cf. ISO 6707).

===== CityGML Feature =====
* '''LoD1:''' not available
* '''LoD2:''' not available
* '''LoD3:''' ''bldg:Window''

===== Geometry =====
;'''''gml:MultiSurface'''''
:see also [[Modeling Guide for 3D Objects - Part 1: Basics (Rules for Validating GML Geometries in CityGML)#gml:MultiSurface|Modeling Guide for 3D Objects - Part 1]]

* A '''window''' consists only of surfaces which are either '''visible from the outside''' of the building, building part or building installation ( case A, B or C ) or consists of '''solids''' ( case D ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
[[image:RechteckFenster-Detail-0.png|250px]]
</td>
<td width="250">
[[image:RechteckFenster-Detail-0-Texture.png|250px]]
</td>
<td width="250">
[[image:RechteckFenster-Detail-1-Flaeche.png|250px]]
</td>
<td width="250">
[[image:RechteckFenster-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
[[image:RechteckFenster-Schnitt-Detail-0.png|250px]]
</td>
<td>
[[image:RechteckFenster-Schnitt-Detail-0-Texture.png|250px]]
</td>
<td>
[[image:RechteckFenster-Schnitt-Detail-1-Flaeche.png|250px]]
</td>
<td>
[[image:RechteckFenster-Schnitt-Detail-1.png|250px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Window as a simple surface)
</td>
<td>
'''Case B''' (Window as a textured surface)
</td>
<td>
'''Case C''' (Window modeled in detail with surfaces only visible from the outside)
</td>
<td>
'''Case D''' (Window as a solid)
</td>
</tr>
</table>

* In order to ensure a closed outer shell of the building, the windows should '''not''' be modeled '''in an opened state''' ( case A ) but '''in closed condition''' ( case B ).

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="500">
[[image:Fenster-offen-red-v1.png|500px]]
</td>
<td width="500">
[[image:Fenster-geschlossen-red-v1.png|500px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
'''Case A''' (Windows opened)
</td>
<td>
'''Case B''' (Windows closed)
</td>
</tr>
</table>

===== Attributes =====
;''bldg:lod3MultiSurface''
:Zeigt auf die LOD3 Geometrie

===== Examples =====

<table border="0" cellspacing="6">
<tr align="left" valign="top">
<td width="250">
'''Simple Window'''
</td>
<td width="250">
'''Simple Window with Embrasure'''
</td>
<td width="250">
'''Detailled Window'''
</td>
</tr>
<tr align="left" valign="top">
<td width="250">
[[image:Beispiel-Fenster-GanzEinfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Fenster-Einfach-Red-V1.png|300px]]
</td>
<td width="250">
[[image:Beispiel-Fenster-Komplex-Red-V1.png|300px]]
</td>
</tr>
<tr align="left" valign="top">
<td>
Number of Polygons (Complete Model) = 28
</td>
<td>
Number of Polygons (Complete Model) = 412
</td>
<td>
Number of Polygons (Complete Model) = 6269
</td>
</tr>
</table>

----
----

=== <span id ="ExtendedModeling">Extended Modeling</span> ===
The Extended Modeling covers the modeling of frequently appearing '''architectural building components''' which significantly form the building's outer appearence. These building components are modeled as '''building installations''' as a general rule.
-----
-----
==== <span id="Balconies">Balconies</span> ====

===== Definition =====
'''SIG3D:''' A '''Balcony''' is a platform attached to a building which lies above the terrain level and projects from the building structure.
It is supported by columns or console brackets, and enclosed with a balustrade [cit. en. Wikipedia]. The word's origin lies in the Italian word "balcone", which itself originates from the old-high-german word "balcho".

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====

*'''''gml:Geometry'' <span style="color:#00FF00">recommended</span>'''
** '''Threshold LOD2:'''
*** Modeling only, if the balcony's depth >= 0.5 m;
**** Plane ground-area, if the component's thickness <= 0.5 m;
**** Plane side-walls, if the component's thickness <= 0.5 m;
** '''Threshold LOD3:'''
*** Modeling only, if the balcony's depth >= 0.2 m;
**** Plane ground-Area, if the component's thickness <= 0.2 m;
**** Plane side-walls, if the component's thickness <= 0.2 m;
** '''Modeling principle'''
*** The building contains all geometry-containing border surfaces.
*** The balcony is modeled as a '''Building Installation with Geometry'''. That is without semantic differentiation.
*** The building's volume references (Xlink) to the corresponding boarder surfaces.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Balkon-Prinzip.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modeling principle of a balcony</td>
</tr>
</table>

*'''''bldg:boundedBy'' <span style="color:#FF0000">not recommended</span>'''

===== Attributes =====
;''bldg:function''
:Balcony'' (1000); see SIG 3D Codelistrecommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#FF0000">'''not recommended:'''</span> A Balcony is considered as '''one''' building component which is semantically not subdivided any further.

===== Examples =====

<table width="1200px" border="1" cellspacing="0" >

<tr align="left">
<td colspan="6">
'''Balconies'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Real Building
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td rowspan="2" width="200px" valign="top">
[[image:KHH-3-Balkone-01-red.JPG|200px]]
</td>

<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD0.png|200px]]
</td>
<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD1.png|200px]]
</td>
<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD2.png|200px]]
</td>
<td width="200px" valign="top">
[[image:KHH-3-Balkone-01-LOD3.png|200px]]
</td>
</tr>

<tr align="middle">
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/6/6e/KHH-3-Balkone-LOD0-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/c/ce/KHH-3-Balkone-LOD1-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/a/ac/KHH-3-Balkone-LOD2-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/d/d0/KHH-3-Balkone-LOD3-V01.gml CityGML download]
</td>
</tr>


<tr align="left">
<td colspan="6">
Above terrain level, projected from the building structure --> Balcony
</td>
</tr>
</table>

<table width="1200px" border="1" cellspacing="0">

<tr align="middle">
<td rowspan="2" width="200px" valign="top">
[[image:Eckbalkon-03-red.png|200px]]
</td>

<td width="200px" valign="top">
[[image:Eckbalkon-LOD0-01.png|200px]]
</td>
<td width="200px" valign="top">
[[image:Eckbalkon-LOD1-01.png|200px]]
</td>
<td width="200px" valign="top">
[[image:Eckbalkon-LOD2-01.png|200px]]
</td>
<td width="200px" valign="top">
[[image:Eckbalkon-LOD3-02.png|200px]]
</td>

<tr align="middle">
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/9/96/Eckbalkon-LOD0-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/4/4a/Eckbalkon-LOD1-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/7/77/Eckbalkon-LOD2-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[http://quality.citygmlwiki.org/images/5/56/Eckbalkon-LOD3-V01.gml CityGML download]
</td>

</tr>
<tr align="left">
<td colspan="6">
Above terrain level, partly projected from the building structure, not bounded by 3 walls --> Balcony (no Loggia)
</td>
</tr>
</table>

-----
-----




==== Loggias ====

===== Definition =====
'''SIG3D:''' A '''Loggia''' is an enclosed on top exterior room within the building footprint, which is surrounded by '''3''' walls at full storey height. From an architectonical point of view, a '''Loggia''' (from the Italian) is a room within a building, which opens to the exterior area by means of archs or other constructional appliances. At ground floor level, Loggias create a passage between the interior area and the exterior area. At upper floor levels, Loggias are used as connection passages or as outdoor seating.

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">not recommended</span>'''

*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** '''Threshold LOD2:'''
*** Modeling only, if the Loggia's depth >= 0.5 m;
** '''Threshold LOD3:'''
*** Modeling only, if the Loggia's depth >= 0.2 m;
** '''Modeling Principle'''
*** The building contains all geometry-containing boundary surfaces

*** The Loggia (BuildingInstallation) '''references (Xlink)''' to the building's corresponding boundary surfaces. If the Loggia's floor is not part of the exterior building structure, it will be modeled as boundary surface at the building installation.
*** The building's volume references (Xlink) to the building's corresponding boundary surfaces.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Loggia-Prinzip-v2.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modeling Principle of a Loggia</td>
</tr>
</table>


===== Attributes =====
;''bldg:function''
:Loggia (1001); see SIG 3D Codelist recommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> A Loggia is considered as a building component which semantically consists of the building's boundary surfaces and possibly an exterior floor surface.

===== Examples =====

<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="left">
<td colspan="6">
'''Loggien'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Real Building
</td>
<td>
ALKIS (German Cadastral Data)
</td>
<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z09.png|200px]]
Interior Loggia
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z09.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z09.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_01.jpg|200px]]
[http://quality.citygmlwiki.org/images/9/9a/Loggia-01-CityGML-LOD2-V1.gml CityGML download]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z12.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z12.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_01.jpg|200px]]
[http://quality.citygmlwiki.org/images/9/9a/Loggia-01-CityGML-LOD2-V1.gml CityGML download]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z13.png|200px]]
Partly set back ground floor
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z13.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z14.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_02.jpg|200px]]
[http://quality.citygmlwiki.org/images/6/63/Loggia-02-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z13.png|200px]]
Multi-storey building with interior Loggias
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z15.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z14.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_03.jpg.png|200px]]
[http://quality.citygmlwiki.org/images/c/c2/Loggia-03-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z16.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z16.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_03.jpg.png|200px]]
[http://quality.citygmlwiki.org/images/c/c2/Loggia-03-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Loggia_Z17.png|200px]]
Multi-storey building, Loggias across the whole front-width and height
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z17.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z17.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_04.jpg|200px]]
[http://quality.citygmlwiki.org/images/d/d8/Loggia-04-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z18.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z17.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_04.jpg|200px]]
[http://quality.citygmlwiki.org/images/d/d8/Loggia-04-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Loggien_halbe_Breite-05-Foto-V1.png|200px]]
Loggias across half the front-width (row house)
</td>
<td width="200px" valign="bottom">
[[image:|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:|200px]]
Kamen Am Langen Kamp 25
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_05.jpg|200px]]
[http://quality.citygmlwiki.org/images/a/a9/Loggia-05-CityGML-LOD2-V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Vorgebaute_Loggien-06-Foto-V1.jpg|200px]]
Projecting Loggias
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Loggia_Z19.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Loggia_Z14.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Loggia_Z19.png|200px]]
[http://quality.citygmlwiki.org/images/f/f6/Loggia-06-CityGML-LOD2_V1.gml CityGML download] *
</td>
<td width="200px" valign="bottom">
</td>
</tr>
</table>
* In this example, the geometry is modeled within the <code>lod2Solid</code> but not within the specified <code>BoundarySurface</code> elements (opposed to the standard)!

-----
-----

==== Thoroughfare ====

===== Definition =====
SIG3D: An open '''Thoroughfare''' is a part of a building at ground level for '''vehicles''' to drive through the building. It is bounded by walls and a roof.

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">not recommended</span>'''



*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** Threshold LOD2 / LOD3:
*** Modeling only, if the Thoroughfare's depth and height >= 2 m;
** '''Modeling Principle''' (Thoroughfare in a building)
*** The building contains all geometry-containing boundary surfaces.
*** The Thoroughfare (BuildingInstallation) '''references (Xlink)''' to the building's corresponding boundary surfaces.
*** The building's volume references (Xlink) to the building's corresponding boarder surfaces.<table border="0" cellspacing="6"><tr align="left" valign="center"><td width="600">[[image:Durchfahrt-Prinzip.png|600px]]</td></tr><tr align="center" valign="top"><td>Modeling Principle of a Thoroughfare</td></tr></table>
** '''Modeling Principle''' (Shared Thoroughfare through two buildings)
*** Each building contains all geometry-containing boundary surfaces
*** The Thoroughfare (BuildingInstallation) is assigned to the building which contains the greater part of the Thoroughfare. The Thoroughfare '''references (Xlink)''' to the building's corresponding boarder surfaces and complements the Thoroughfare with bounding geometry at the BuildingInstallation.
*** The building's volume references (Xlink) to the building's corresponding boarder surfaces.<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Durchfahrt-Prinzip-Var-2.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modeling Principle of a shared Thoroughfare</td>
</tr>
</table>

<br />
'''Note:''' The modeling of buildings with a closed building construction is described in [[#GebäudeInGeschlossenerBauweise|Kapitel 3.7]]

===== Attributes =====
;''bldg:function''
:Thoroughfare (1002); see SIG 3D codelist recommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> A Thoroughfare is considered as a building component which semantically consists of the building's boundary surfaces and possibly an exterior floor surface.

===== Examples =====
<table width="1200px" border="1" cellspacing="0" style="border:thin">

<tr align="left">
<td colspan="6">
'''Thoroughfares'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Actual Example
</td>
<td>
ALKIS
</td>
<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Durchfahrt_Z26.png|200px]]
Thoroughfare inside of a building
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z26.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z26.png|200px]]
[http://quality.citygmlwiki.org/images/0/05/Durchfahrt-01-CityGML-LOD1-V2.gml CityGML download]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-01-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/2/20/Durchfahrt-01-CityGML-LOD2-V2.gml CityGML download]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Zwei_Gebaeude_mit_gemeinsamer_Durchfahrt-02-Foto-V1.jpg|200px]]
Two buildings with a shared Thoroughfare
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z27.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z26.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-02-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/a/a5/Durchfahrt-02-CityGML-LOD2-V4.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

Two buildings with separate Thorouoghfares
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z28.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z27.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-03-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/f/f1/Durchfahrt-03-CityGML-LOD2-V2.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">

Two offset buildings with separate Thoroughfares
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z29.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z29.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-04-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/4/4c/Durchfahrt-04-CityGML-LOD2-V1.gml CityGML download]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Zwei_Gebaeude_mit_einseitiger_Durchfahrt-05-Foto-V1.jpg|200px]]
Two buildings with onesided Thoroughfare
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z27.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:Durchfahrt-05-LOD2.jpg|200px]]<br />
[http://quality.citygmlwiki.org/images/e/eb/Durchfahrt-05-CityGML-LOD2-V1.gml CityGML herunterladen]<br />
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Zwei_Gebaeude_mit_Verbindungstrakt-01-Foto-V1.jpg|200px]]
Two buildings with a connection section
</td>
<td width="200px" valign="bottom">
[[image:ALKIS_Durchfahrt_Z31.png|200px]]
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z31.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Durchfahrt_Z31.png|200px]]
</td>
<td width="200px" valign="bottom">
</td>
</tr>

<tr align="middle">
<td width="200px" valign="bottom">
[[image:Real_Durchfahrt_Z53.png|200px]]
Upper floor Thoroughfare
</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">

</td>
<td width="200px" valign="bottom">
[[image:LOD1_Durchfahrt_Z53.png|200px]]
</td>
<td width="200px" valign="bottom">
[[image:LOD2_Durchfahrt_Z53.png|200px]]
</td>
<td width="200px" valign="bottom">
</td>
</tr>
</table>

==== Dormers / Zwerchhaus (Zwerchgiebel)====

===== Definition =====
'''SIG3D:'''
'''SIG3D:''' A '''dormer'''' is a structural element of a building that protrudes from the plane of a sloping roof surface. Dormers are used, either in original construction or as later additions, to create usable space in the roof of a building by adding headroom and usually also by enabling addition of windows [Wikipedia].

A '''dormer''' does not lie on the same plane as the building's exterior wall. The dormer (or the dormer's footprint) has a minimum offset of 0,5 m and lies inside the building's footprint.

'''SIG3D:''' The '''Zwerchhaus''' is a one or more story installation of a sloping roof surface. It consists of a gable and its own roof. The !!!Zwerchgiebel!!! follows the exterior wall's building line. That represents the difference between a !!!Zwerchhaus!!! and a gable, because a gable does not have to follow the building line. The roof of the !!!Zwerchhaus!!! is often designed as a ridge roof. The ridge follows cross to the main roof's ridge. So the rainwater pipes continue in an orthogonal way to each other.

'''Note:''' The '''zwerchhaus''' is not modeled as a part of the building installation, but as a building's boundary surface itself.

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">not recommended</span>'''

*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** Threshold LOD2:
*** Modeling only, if the dormer's height >= 2 m;
** Threshold LOD3:
***
** '''Modeling Principle'''
*** The building contains all geometry-containing boundary surfaces of the building structure. To close the building's volume, a ClosureSurface is modeled into the roof's gap.
*** The dormer (BuildingInstallation) '''contains all geometry-containing boundary surfaces''' of the dormer. To close the volume, either a ClosureSurface is modeled or it is closed by referencing to the building's corresponding ClosureSurface (Xlink to OrientableSurface).
*** The building's volume, the building structure's volume and the volume of the dormer ('''CompositeSolid''') reference (Xlink)to the corresponding boundary surfaces of the building structure and dormer.

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Dachgaube-Prinzip.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modelling Principle of a dormer</td>
</tr>
</table>

===== Attributes =====
;''bldg:function''
:Dormer (1003); see SIG 3D codelisten recommendation for[http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> A dormer is considered as a building component which semantically consists of the building's boundary surfaces.

===== Examples =====
<table width="1200px" border="1" cellspacing="0" >

<tr align="left">
<td colspan="6">
'''Dormer'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Actual Example
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="top">

</td>

<td width="200px" valign="top">

</td>
<td width="200px" valign="top">

</td>
<td width="200px" valign="top">
[[image:DachgaubeClosure-01-LOD2.jpg|200px]]
[http://quality.citygmlwiki.org/images/b/b5/DachgaubeClosure-V1.gml CityGML download]
</td>
<td width="200px" valign="top">

</td>
</tr>
</table>

<table width="1200px" border="1" cellspacing="0" >

<tr align="left">
<td colspan="6">
'''Zwerchhaus (Zwerchgiebel)'''
</td>
</tr>

<tr align="middle" valign="top">
<td>
Actual Example
</td>

<td>
CityGML LOD0
</td>
<td>
CityGML LOD1
</td>
<td>
CityGML LOD2
</td>
<td>
CityGML LOD3
</td>
</tr>

<tr align="middle">
<td width="200px" valign="top">
[[image:Zwerchhaus-Foto-V3.jpg|200px]]
</td>

<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD0-v02.png|170px]]
[http://quality.citygmlwiki.org/images/a/a0/Zwerchgiebel-LOD0-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD1-v02.png|170px]]
[http://quality.citygmlwiki.org/images/3/32/Zwerchgiebel-LOD1-V01.gml CityGML download]
</td>
<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD2-v02.png|170px]]
[http://quality.citygmlwiki.org/images/4/4b/Zwerchgiebel-LOD2-V02.gml CityGML download]
</td>
<td width="200px" valign="top">
[[image:Zwerchgiebel-LOD3-v02.png|170px]]
[http://quality.citygmlwiki.org/images/d/d4/Zwerchgiebel-LOD3-V01.gml CityGML download]
</td>

</tr>
</table>

==== Arcades / Architrav ====

===== Definition =====
'''SIG3D:''' An arcade is a succession of arches, each counter thrusting the next, supported by columns or piers, or a covered walk enclosed by a line of such arches on one or both sides. In warmer or wet climates, exterior arcades provide shelter for pedestrians.[Wikipedia]

'''SIG3D:''' An '''architrave''' (from Italian architrave, from Greek ἀρχι, archi- and Latin trabs, bar) is the lintel or beam that rests on the capitals of the columns. It is an architectural element in Classical architecture. In the ancient world, it was also called Epistyl because it was commonly built on pillars.[Wikipedia]

===== CityGML Feature =====
* '''LOD1:''' not available
* '''LOD2:''' ''bldg:BuildingInstallation''
* '''LOD3:''' ''bldg:BuildingInstallation''

===== Geometry =====
*'''''gml:Geometry'' <span style="color:#FF0000">net recommended</span>'''

*'''''bldg:boundedBy'' <span style="color:#00FF00">recommended</span>'''
** '''Threshold LOD2:'''
*** Threshold-values for the modelling of beams: all sides of the beam's BoundingBox are >= 0.5 m
** '''Modelling principle'''
*** The building contains all geometry-containing boundary surfaces
*** The Arcade (BuildingInstallation) '''references (Xlink)''' to the building's corresponding boundary surfaces
*** The building's volume references (Xlink) to the building's corresponding boundary surfaces

<table border="0" cellspacing="6">
<tr align="left" valign="center">
<td width="600">
[[image:Arkade-Prinzip.png|600px]]
</td>
</tr>
<tr align="center" valign="top">
<td>
Modelling principle of an arcade</td>
</tr>
</table>

===== Attributes =====
;''bldg:function''
:Arcade (1009); see SIG 3D codelist recommendation for [http://www.sig3d.org/codelists/Handbuch-SIG3D/building/2.0/CL-V1.0/BuildingInstallation_function.xml ''bldg:BuildingInstallation --> function'' ]
;''bldg:boundedBy''
:<span style="color:#00FF00">'''recommended:'''</span> An Arcade is considered as a building component which semantically consists of the building's boundary surfaces.

===== Examples =====

{| width="1200px" cellspacing="0" border="1" style="border:thin"
|- align="left"
| colspan="6" |
'''Arcades'''

|- valign="top" align="center"
|
Actual example

|
ALKIS

|
CityGML LOD0

|
CityGML LOD1

|
CityGML LOD2

|
CityGML LOD3

|- align="center"
| width="200px" valign="bottom" |
[[Image:Real Arkaden.png|200px]]

| width="200px" valign="bottom" |
[[Image:ALKIS Arkaden.png|200px]]

| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
[[Image:LOD1 Arkaden.png|200px]]

| width="200px" valign="bottom" |
[[Image:LOD2 Arkaden V1.png|200px]]

| width="200px" valign="bottom" |
|- align="center"
| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
| width="200px" valign="bottom" |
[[Image:LOD2 Arkaden V2.png|200px]]

| width="200px" valign="bottom" |
|}

<br>

{| width="1200px" cellspacing="0" border="1"
|- align="left"
| colspan="6" |
'''Arcade'''

|- valign="top" align="center"
|
Real Building



|
CityGML LOD0

|
CityGML LOD1

|
CityGML LOD2

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CityGML LOD3

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[[Image:Arkaden-01-Foto-V1.jpg|200px]]



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[[Image:Arkade-LOD0-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/4/43/Arkade-LoD0-Beispiel-Wiki-01-V01.gml CityGML download]

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[[Image:Arkade-LOD1-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/2/21/Arkade-LoD1-Beispiel-Wiki-01-V01.gml CityGML download]

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[[Image:Arkade-LOD2-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/e/e5/Arkade-LoD2-Beispiel-Wiki-01-V01.gml CityGML download]

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[[Image:Arkade-LOD3-v01-red.png|200px]] [http://quality.citygmlwiki.org/images/f/fb/Arkade-LoD3-Beispiel-Wiki-01-V01.gml CityGML download]

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