How to rasterize walls for grid calculations
Revision as of 09:24, 15 August 2023 by Rudolf@tygron.nl (talk | contribs) (Created page with "For some calculations, it may be relevant to know where the walls of structures exist. This is a trivial consideration, but a bit more complex to implement in a geographical calculation. However, by using some localized checks on the behavior and local changes of elevation models, it is possible to create a spatial calculation which can find the locations of walls of structures. {{editor location|Overlays}} {{editor steps|title=rasterize walls for grid calculations | A...")
For some calculations, it may be relevant to know where the walls of structures exist. This is a trivial consideration, but a bit more complex to implement in a geographical calculation. However, by using some localized checks on the behavior and local changes of elevation models, it is possible to create a spatial calculation which can find the locations of walls of structures.
How to rasterize walls for grid calculations:
- Add a Heightmap Overlay, configured as DTM, to the Project (if it does not exist yet)
- Add a Heightmap Overlay, configured as DSM, to the Project (if it does not exist yet)
- Add an Average Overlay to the Project.
Set the averaging to the DSM Heightmap Overlay.
Set the averaging distance to approximately 2.5 times the grid cell size. - Add a Combo Overlay to the Project with the following configuration:
A: DTM Overlay
B:DSM Overlay
C:Average Overlay of DSM
Formula: AND(GT(SUB(C, A), 1), GT(SUB(C, B), 1)) - Modify the legend of the Combo Overlay to have only the following values:
Value 0: No wall
Value 1: Wall - Rename the Combo Overlay to "Walls"