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Acquiring elevations for
3D Buildings
Jairo Castillo
The City of Calgary
2013 Calgary Floods
In case of future flooding, the inspector
can access building information
that identifies where the minimum
elevation of t...
How 3D Buildings were created?
LiDAR unclassified
LiDAR Classified
Buildings as dgn file
LiDAR and Buildings
3D Buildings have
unique Structure ID
attributes and the
project was to
calculate three
Elevations per building
(Rooftop, ...
It was a challenge to
process and find heights
of more than 418,000
individual buildings in
the City of Calgary
Points were generated
for every vertex on the
multipatch file
Multipatch Shapefile:
Consists of a number of
surface patches.
“ESRI Shapefile Technical Description” July 1998 . ESRI
<ht...
Rooftop Elevation Workbench
Problem: The Minimum
Elevation of the
Building data does not
fit the surface of the
ground.
Part of the building is in
the ground.
Solution: 3D Buildings
have been transformed as
Footprint (2D) features
Key Transformer:
SurfaceFootprintReplacer
The footprint was
densified every metre
and the vertices were
extracted and
superimposed over the
DEM.
StatisticCalculator
extracts a min and max
value in Z for every
building
FeatureMerger selects
the minimum and
maximum elevation
The workbench creates
a point where the
ground has the
maximum elevation
along the footprint of
the building.
The workbench creates
a point where the
ground has the
minimum elevation
along the footprint of
the building.
Final Attribute table
Ground Elevation Workbench
Thank you!
Jairo Castillo
jairo.castillo@calgary.ca
The City of Calgary
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Gathering Different Elevations for 3D Buildings from DEM

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The 3D buildings were extracted from LiDAR data collected by the City of Calgary but there were no attributes and the type of file of 3D buildings was a geodatabase. Based on what happened with flooding in 2013 the City of Calgary inspectors wanted to know in the event of future flooding, the lowest elevation of the houses or buildings to inspect right away to determine if the building is affected or not by the flooding. The elevations gathered were:
1. The lowest ground elevation of the building (x, y and z).
2. The highest ground elevation of the building (x, y and z).
3. The highest elevation of the building (x, y and z).

These elevations were calculated for more than 400,000 buildings in the City of Calgary and the whole process to gather the elevations were processed from 2 different workbenches, one using the DEM to extract the ground elevations and the other workbench was using the real 3D building elevations to calculate the highest point from every single building.

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Gathering Different Elevations for 3D Buildings from DEM

  1. 1. Acquiring elevations for 3D Buildings Jairo Castillo The City of Calgary
  2. 2. 2013 Calgary Floods
  3. 3. In case of future flooding, the inspector can access building information that identifies where the minimum elevation of the building is to check if the building has been affected. This is important as inspectors often only view the front of residences and buildings.
  4. 4. How 3D Buildings were created?
  5. 5. LiDAR unclassified
  6. 6. LiDAR Classified
  7. 7. Buildings as dgn file
  8. 8. LiDAR and Buildings
  9. 9. 3D Buildings have unique Structure ID attributes and the project was to calculate three Elevations per building (Rooftop, Ground Min Elev, and Ground Max Elev)
  10. 10. It was a challenge to process and find heights of more than 418,000 individual buildings in the City of Calgary
  11. 11. Points were generated for every vertex on the multipatch file
  12. 12. Multipatch Shapefile: Consists of a number of surface patches. “ESRI Shapefile Technical Description” July 1998 . ESRI <http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf >
  13. 13. Rooftop Elevation Workbench
  14. 14. Problem: The Minimum Elevation of the Building data does not fit the surface of the ground.
  15. 15. Part of the building is in the ground.
  16. 16. Solution: 3D Buildings have been transformed as Footprint (2D) features Key Transformer: SurfaceFootprintReplacer
  17. 17. The footprint was densified every metre and the vertices were extracted and superimposed over the DEM.
  18. 18. StatisticCalculator extracts a min and max value in Z for every building
  19. 19. FeatureMerger selects the minimum and maximum elevation
  20. 20. The workbench creates a point where the ground has the maximum elevation along the footprint of the building.
  21. 21. The workbench creates a point where the ground has the minimum elevation along the footprint of the building.
  22. 22. Final Attribute table
  23. 23. Ground Elevation Workbench
  24. 24. Thank you! Jairo Castillo jairo.castillo@calgary.ca The City of Calgary

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