(1) The document presents a methodology for generalizing 3D building models within CityGML for disaster and emergency management. (2) The methodology involves 6 steps: derivation of coarse levels of detail, projection of outlier buildings, simplification of ground plans, aggregation, and reconstruction of simplified wall elements. (3) The methodology was implemented in C++ and able to generalize 3D building models to support disaster response and recovery by providing different levels of detail for analysis and visualization.

1. Generalization Building
Model Using CityGML
Oriented Literature Review
Digital Photogrammetry
Martin Deikom
Muhammad Irsyadi Firdaus 1

2. 1
2
Literature
Review
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3. The main purpose
Generalization of 3D buildings
within CityGML For Disaster and
Emergency Management
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4. Introduction (1) The benefits of 3D Geo-
information one of them is
for disaster and emergency
management
Open Geospatial Consortium standard, is
being used to model and represent
buildings in different LoDs (LoD0–LoD4),
but it does not provide methods to
generate different LoDs automatically4

5. Introduction (2)
• Generalization based on CityGML specifications
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6. Methodology
A generalization workflow presented in this
Figure is composed of six steps as the
following:
(1) derivation of coarse LoDs;
(2) projection of outlier of building models;
(3) Simplification of segments of the ground
plans extracted from the outlier of
buildings;
(4) aggregation; and
(5) reconstruction of simplified segments of
wall elements. Subsequently, generalized
buildings are visualized offline. A brief
summary of these steps are given below.
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7. Simplification of the 2D ground plan
Simplification of offset taking length of neighboring
edges into account: original edges of offset (a),
extension of the larger edge and identification of
shortest edge (b), and final result of simplification
process (c).
Simplification of a segment with a sharp
corner: Original corner formed by two large
edges (a), creation of a triangle with center
point (b), and simplified corner (c).
Removal of sharp corner: original shape of corner
(a), reduction of longer edges (b), and the result of
the removal of newly formed smaller edges (c).
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8. Results
a. original building b. simplified models c. aggregated models
Aggregation of simplified models
3D building models of a portion of Putrajaya, Malaysia,
visualized in LandXplorer CityGML Viewer 2009.
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Implementation
Generalization of 3D building
models was implemented in a
C++ application. The platform,
Microsoft Visual Studios 2008,
runs on a PC Pentium (R)
Dual-Core CPU 2.10 GHz, 2.00
GB RAM, and Microsoft
Windows 2007.

9. Geo-information Requirements Analysis for
Industrial Fire Disaster
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This Table is involves the 3D geo-information
requirements of the phases of mitigation, preparation,
response and recovery for industrial fire disaster
management.
Building, transportation, protected sites, energy
resources, production and industrial facilities, and
population distribution and demography feature
types are required with their LOD2-4 information.
That is to say, these data sets are essential for 3D
geo-information to manage industrial fire disaster.

10. CONCLUSIONS
• We can generate 3D building model using framework of CityGML
• We argue that 3D geo-information that provide advanced
visualisation, analysis and interaction to the actors involved in DEM
have the potential to improve the DEM processes.
• 3D geo-information can resolve many perception problems and
improve the activity management
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11. Thank you for your attention
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