Open Geospatial Consortium Inc. Date: 2007-06-17 Reference number of this OGC® project document: OGC 07-062 Version: 0.4.0 Category: OGC Best Practices Document Editors: Gerhard Gröger, Thomas H. Kolbe, Angela Czerwinski Candidate OpenGIS® CityGML Implementation Specification (City Geography Markup Language) Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. To obtain additional rights of use, visit http://www.opengeospatial.org/legal/. Warning This is an OGC Best Practices document. It is not an OGC Standard and may not be referred to as an OGC Standard. It is subject to change without notice. However, this document is an official position of the OGC membership on this particular technology topic. Document type: OpenGIS® Engineering Report Document subtype: Application Schema for the Geography Markup Language 3 (GML 3.1.1) Document stage: OpenGIS® Best Practices Document Document language: English OGC 07-062 Contents i. Preface....................................................................................................................... vi ii. Submitting organizations......................................................................................... vi iii. Submission contact points ....................................................................................... vi iv. Revision history .......................................................................................................vii v. Changes to the OGC® Abstract Specification ......................................................vii vi. Acknowledgments ...................................................................................................vii Foreword ...........................................................................................................................viii 0 Introduction............................................................................................................... x 0.1 Motivation........................................................................................................ x 0.2 Historical background...................................................................................... x 1 Scope...........................................................................................................................1 2 Conformance ............................................................................................................. 2 3 Normative references................................................................................................ 2 4 Conventions ............................................................................................................... 3 4.1 Abbreviated terms............................................................................................ 3 4.2 UML Notation.................................................................................................. 4 4.3 XML-Schema................................................................................................... 5 5 Overview of CityGML .............................................................................................. 7 6 General characteristics of CityGML....................................................................... 9 6.1 Multi-scale modelling (5 levels of detail, LOD).............................................. 9 6.2 Coherent semantical-geometrical modelling ................................................. 10 6.3 Closure surfaces............................................................................................. 10 6.4 Terrain Intersection Curve (TIC)................................................................... 11 6.5 Dictionaries and code lists for enumerative attributes................................... 11 6.6 External references......................................................................................... 12 6.7 City object groups.......................................................................................... 12 6.8 Appearances................................................................................................... 12 6.9 Prototypic objects / scene graph concepts ..................................................... 13 6.10 Generic city objects and attributes................................................................. 13 6.11 Application Domain Extensions (ADE) ........................................................ 13 7 Spatial model ........................................................................................................... 15 7.1 Geometric-topological model ........................................................................ 15 7.2 Implicit geometries, prototypic objects, scene graph concepts...................... 18 8 Appearance model................................................................................................... 21 ii Copyright © 2007 Open Geospatial Consortium, Inc. All Rights Reserved. OGC 07-062 8.1 Relation between appearances, features and geometry.................................. 21 8.2 Appearance and SurfaceData......................................................................... 22 8.3 Material.......................................................................................................... 23 8.4 Texture and texture mapping ......................................................................... 24 8.5 Related concepts ............................................................................................ 30 8.6 Material model in previous CityGML versions [deprecated]........................ 30 9 Thematic model ....................................................................................................... 33 9.1 Top level classes ............................................................................................ 33 9.2 Digital Terrain Model (DTM)........................................................................ 36 9.3 Building model............................................................................................... 40 9.3.1 Building and building part........................................................................................ 42 9.3.2 Boundary surfaces.................................................................................................... 46 9.3.3 Outer building installations ...................................................................................... 49 9.3.4 Openings .................................................................................................................. 50 9.3.5 Building Interior....................................................................................................... 51 9.3.6 Modelling building storeys using CityObjectGroups............................................... 53 9.3.7 External code lists .................................................................................................... 53 9.4 Water bodies .................................................................................................. 54 9.4.1 Water body............................................................................................................... 56 9.4.2 Boundary surfaces.................................................................................................... 56 9.4.3 External code lists .................................................................................................... 58 9.5 Transportation objects.................................................................................... 59 9.5.1 Transportation complex ........................................................................................... 62 9.5.2 Subclasses of transportation complexes................................................................... 64 9.5.3 External code lists .................................................................................................... 65 9.6 Vegetation objects.......................................................................................... 66 9.6.1 Vegetation object ..................................................................................................... 68 9.6.2 Solitary vegetation objects ....................................................................................... 68 9.6.3 Plant cover objects ................................................................................................... 69 9.6.4 External code lists .................................................................................................... 69 9.6.5 Example of a CityGML dataset................................................................................ 69 9.7 City furniture.................................................................................................. 71 9.7.1 City furniture object ................................................................................................. 72 9.7.2 External code lists .................................................................................................... 73 9.7.3 Example of CityGML dataset .................................................................................. 73 9.8 Land use......................................................................................................... 75 9.8.1 Land use object ........................................................................................................ 76 9.8.2 External code lists .................................................................................................... 76 9.9 City object groups.........................................................................................