Technische Universität Berlin
Department of Geoinformation Science
Current Status and Roadmap of CityGML
Thomas H. Kolbe
Director
Institute for Geodesy and Geoinformation Science
Berlin University of Technology
thomas.kolbe@tu-berlin.de
26th of June, 2011
Joint ISPRS 3DCMA & 3D GeoInfo Conference Wuhan, China
2011/06/26
Department of Geoinformation Science
Queries to a 3D City Model / 3D GIS:
• How many buildings, monuments, trees?
• How many storeys?
• Total sealed area?
• From which windows can I see place XY?
• What is the total window area of the buildings?
• Where are the entrances / exits?
• What is the energy demand for heating and electricity?
Image: Berlin Partner, Google
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
3D City Modelling
Department of Geoinformation Science
… is far more than
the 3D visualization
of reality
In fact, the geometry
and its appearance
are only one aspect
of an entity!
Key issue:
Semantic Modelling
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Example for a Semantic Building Model
Department of Geoinformation Science
3D-Modell: Stadt Coburg
BuildingPart
BuildingInstallation
(Dormer)
Building
BuildingPart
Building
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T. H. Kolbe – Status and Roadmap of CityGML
Building surface
(WallSurface)
2011/06/26
Urban Information Modelling with CityGML
Department of Geoinformation Science
Application independent Geospatial Information Model
for semantic 3D city and landscape models
 comprises
different thematic areas
(buildings, vegetation, water, terrain, traffic etc.)
 data
model (UML) according to ISO 191xx standard family
 exchange
format results from rule-based mapping of the
UML diagrams to a GML3 application schema
 Adopted
OGC standard since 08/2008
CityGML represents
 3D
 in
6
geometry, 3D topology, semantics and appearance
5 discrete scales (Levels of Detail, LOD)
T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Multi-scale modelling: 5 levels of details
Department of Geoinformation Science
LOD 0 – Regional model

2.5D Digital Terrain Model
LOD 1 – City / Site model

“block model“ w/o roof structures
LOD 2 – City / Site model

textured, differenciated roof structures
LOD 3 – City / Site model

detailed architecture model
LOD 4 – Interior model

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“walkable“ architecture models
T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Modular Structure of CityGML
Department of Geoinformation Science
Bridge
Tunnel
WaterBody
Vegetation
Transportation
Relief
LandUse
CityObjectGroup
CityFurniture
Building
Application Domain Extensions (ADE)
Generics
Appearance
…
CityGML Core
OGC GML 3.1.1
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Department of Geoinformation Science
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
International Adoption of CityGML
Department of Geoinformation Science
 Cities
/ Municipalities
 e.g. nearly all German cities with 3D city models; Rotterdam
(NL), Zurich (CH), Geneva (CH), Vancouver (CA), Paris (FR),
Marseille (FR), Istanbul (TR), Kuala Lumpur (MY), Yokohama
(JP), Doha (Katar); limited awareness in USA (Boston, Chicago)
 Organisations
 e.g. IGN France, Ordnance Survey UK, State mapping agencies
of Bavaria and North-Rhine Westphalia in Germany, BIMTAS in
Istanbul, many Research Institutes and Universities
 CityGML
is being used as a reference in the
European INSPIRE Initiative
 INSPIRE Building model is nearly identical to CityGML
 The
new national 3D standard of The Netherlands will be
based on CityGML
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Semantic 3D City Model of Berlin
Department of Geoinformation Science
www.virtual-berlin.de
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T. H. Kolbe – Status and Roadmap of CityGML
>500,000 buildings were
automatically reconstructed
using 2D building footprints
from cadastre and airborne
LIDAR data.
Textures were automatically
extracted from oblique aerial
images.
Semantic information is also
transferred from cadastre.
2011/06/26
New Applications: Solar Potential Analysis
Department of Geoinformation Science
Example: Solar Atlas Berlin

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Semantic information (here: estimated solar energy production)
is used both to cartographically style the visualization and to
provide the values shown in the „information balloons“
T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
3D Visualisation of CityGML Models
Department of Geoinformation Science
KML /
COLLADA
One 3D City Model


KML
may comprise
(or link) thematic
data from different
applications
can be stored and
exchanged as one
CityGML dataset
KML /
COLLADA
Multiple, different visualizations with
application specific cartographic stylings
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
3DCityDB – Open Source CityGML Software
Department of Geoinformation Science
Free software to manage and visualize CityGML data:
http://www.3dcitydb.net
3D City Database (new version 2.0.5)

SQL scripts, PL/SQL functions for Oracle Spatial 10g R2 and above
 Comprehensive documentation (incl. mapping of CityGML to relations)
3DCityDB Import/Export Tool (new version 1.3)

Executable Java binaries; tested with Windows, MacOS X, Linux
 Complete source code, comprehensive documentation
 fast CityGML import/export (supports arbitrary file sizes, even >> 4GB)
 KML/COLLADA exporter
citygml4j (current version 1.0)

Java class library and API for reading and writing CityGML datasets
 Library files for Java5 and Java6
 Source code, comprehensive documentation, tutorials
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Simulation of Multi Utility Infrastructures
Department of Geoinformation Science
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Energy Atlas: Urban Information Fusion
Department of Geoinformation Science
Solar Irradiation LOD1
Heat Emission
Utility Networks
Bild: Hoegner / Stilla, TU München
Energy Atlas
Heating Energy
Geschätzter EnergieRequirements
verbrauch [kwh/a]
Thermal Remote Sensing
Solar Potential
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Department of Geoinformation Science
News for Version 1.1
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
CityGML 1.1 Roadmap
Department of Geoinformation Science
20.08.2008
09.12.2009
26.02.2010
Since March 2010
CityGML 1.0
International OGC Encoding Standard
Formation of the CityGML 1.1 SWG
The Standards Working Group (SWG) is in charge of all
changes of the CityGML specification
Public Call for Change Requests (CR)
17 CRs received which have to be processed by the SWG
SWG processes CRs
CRs have to be discussed and voted on; draft version of the
CityGML 1.1 specification is being created currently
today
July/August 2011
Request for Comments (RFC)
The candidate CityGML 1.1 specification will be reviewed and
commented on by the public in a 30-day RFC phase
Final editorial changes based on received comments
End of 2011 –
Beginning of 2012
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Release of CityGML 1.1
T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Received Change Requests comprise...
Department of Geoinformation Science
 New thematic modules
 Bridges and Tunnels
 Walls in cities
 Extensions of existing
 Building module
for the representation of
modules
explicit representation of storeys (as own object class)
additional thematic boundary surfaces (OuterCeilingS., OuterFloorS.)
LOD 0 representation (roofprint, footprint as 3D Multipolygons)
 Generic attributes
Unit of measure (e.g. meters, dollars, etc.) can be given for attributes
Grouping of generic attributes and relation with a unique namespace
 Miscellaneous
 Compressed archive format for CityGML (like KMZ)
 Topologic Network Model
 new CityObject attributes relativeToTerrain, relativeToWater
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
CityGML 1.1 Bridge Model
Department of Geoinformation Science
 Similar
/ coherent structure with the Building model
 Bridges may be decomposed into BridgeParts
 Bridges have Thematic Boundary Surfaces (from LOD2) like
WallSurface, RoofSurface, FloorSurface, etc.
 Thematic Boundary Surfaces can have openings (from LOD3)
 Bridges / BridgeParts can have BridgeInstallations (from LOD2)
 in LOD4 they can also have a representation of their interiors given
by BridgeRooms and BridgeFurniture
 All feature types have thematic attributes (like class, function,
and usage)
 Terrain Intersection Curves
 Bridges
and BridgeParts can be further decomposed into
BridgeConstructionElements (required for static stability)
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Bridge Components
Department of Geoinformation Science
BridgePart
BridgeInstallation (here: signalling lamp)
BridgeConstructionElement
BridgePart
BridgeConstructionElement
BridgePart
Bridge
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Bridge Model in UML [draft; simplified]
Visual Paradigm for UML Standard Edition(Technical University Berlin)
Department of Geoinformation Science
<<Feature>>
core::_CityObject
lod3-4Geometry
<<Object>>
core::ImplicitGeometry
<<Feature>>
BridgePart
*
consistsOfBridgePart
* outerBridgeConstruction
<<Feature>>
BridgeConstructionElement
<<Feature>>
Bridge
*
<<Feature>>
_AbstractBridge
*
*
*
*
<<Feature>>
BridgeInstallation
bridgeInstallation
*
*
*
<<Feature>>
BridgeRoom
0..1
interiorBridgeRoom
*
0..1
lod1-4Geometry
lod2-4Geometry
interiorFurniture
*
<<Feature>>
BridgeFurniture
lod4Geometry
<<Geometry>>
gml::_Geometry
lod2-4Geometry
boundedBy
*
lod3-4Geometry
*
boundedBy
<<Feature>>
_Opening
<<Feature>>
Window
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<<Feature>>
Door
* opening
<<Feature>>
RoofSurface
<<Feature>>
_BoundarySurface
0..2
<<Feature>>
WallSurfacee
T. H. Kolbe – Status and Roadmap of CityGML
<<Feature>>
GroundSurface
<<Feature>>
ClosureSurface
2011/06/26
Examples for Bridges in LODs 1-4
Department of Geoinformation Science
LOD 1
LOD 2
LOD 3
LOD 4
Models source: Google 3D Warehouse
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
CityGML 1.1 Tunnel Model
Department of Geoinformation Science
 Similar
/ coherent structure with the Building model
 Tunnels may be decomposed into TunnelParts
 Tunnels have Thematic Boundary Surfaces (from LOD2) like
WallSurface, RoofSurface, GroundSurface, FloorSurface etc.
 Thematic Boundary Surfaces can have openings (from LOD3)
 Tunnels / TunnelParts can have TunnelInstallations (from LOD2)
 in LOD4 they can also have a representation of their interiors given
by HollowSpaces and TunnelFurniture
 All feature types have thematic attributes (like class, function,
and usage)
 Terrain Intersection Curves
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Tunnel Model in UML [draft; simplified]
Visual Paradigm for UML Standard Edition(Technical University Berlin)
Department of Geoinformation Science
<<Feature>>
core::_CityObject
lod3-4Geometry
<<Object>>
core::ImplicitGeometry
<<Feature>>
TunnelInstallation
<<Feature>>
TunnelPart
*
consistsOfTunnelPart
*
<<Feature>>
_AbstractTunnel
*
tunnelInstallation
*
<<Feature>>
Tunnel
*
*
<<Feature>>
HollowSpace
0..1
interiorHollowSpace
*
*
0..1
interiorFurniture
*
<<Feature>>
TunnelFurniture
lod1-4Geometry
lod2-4Geometry
lod4Geometry
<<Geometry>>
gml::_Geometry
lod2-4Geometry
boundedBy
*
lod3-4Geometry
*
boundedBy
<<Feature>>
_Opening
<<Feature>>
Window
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<<Feature>>
Door
* opening
<<Feature>>
RoofSurface
<<Feature>>
_BoundarySurface
0..2
<<Feature>>
WallSurfacee
T. H. Kolbe – Status and Roadmap of CityGML
<<Feature>>
GroundSurface
<<Feature>>
ClosureSurface
29. Februar,
2011/06/26
2008
Example for a Tunnel in LODs 1-4
Department of Geoinformation Science
LOD 1
LOD 2
LOD 3
LOD 4
Tunnel
Tunnel
interior
(cut 1)
Tunnel
interior
(cut 2)
Image source: Karl-Heinz Häfele, KIT
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Modeling a Metro System using CityGML
Department of Geoinformation Science
Metro station + tunnel
Above ground entry to
the metro station
(LOD3 Building)
Digital Terrain
Model (e.g.
in LOD1)
Connecting tunnel between
two metro stations
(Tunnel object, e.g.
in LOD3)
These two objects
also could be
represented as one
Building with
two BuildingParts
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T. H. Kolbe – Status and Roadmap of CityGML
Underground part of
the metro station
(underground LOD3
Building object)
2011/06/26
Summary
Department of Geoinformation Science
 Semantic
3D City Models (= Urban Information Models)
 allow for 3D visualizations AND thematic analyses
 facilitate comprehensive analyses on the urban scale in the fields of
e.g. energy assessment, environmental simulation, urban planning
 CityGML
intended to be used as a basis for standardized
information structuring and data exchange
 extension mechanisms like Generics & ADE provide flexibility
 International
adoption and system implementations
are making steady progress
 Increasing number of cities worldwide are using CityGML
 Active
further development within SIG 3D and OGC
 CityGML 1.1 to be released by end of 2011 / beginning of 2012
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T. H. Kolbe – Status and Roadmap of CityGML
2011/06/26
Research Topics with Relations to CityGML
Department of Geoinformation Science
 3D
city model validation
 3D
generalization
 3D
data integration
 Automatic
extraction of semantic 3D city models
from sensor data or CAD/CG models
 Reconstruction of Building Information Models from CityGML
 Dynamic
 Urban
 (DB)
 3D
models, relation to procedural models
data mining
index structures for efficient visibility analyses
Cartographic Styling of 3D City Models
 Label Placement, Symbolization
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T. H. Kolbe – Status and Roadmap of CityGML
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