How to rasterize walls for grid calculations

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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...")
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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 → Current Situation (Ribbon tab) → Overlays (Ribbon bar)
How to rasterize walls for grid calculations:
  1. Add a Heightmap Overlay, configured as DTM, to the Project (if it does not exist yet)
  2. Add a Heightmap Overlay, configured as DSM, to the Project (if it does not exist yet)
  3. 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.
  4. 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))
  5. Modify the legend of the Combo Overlay to have only the following values:
    Value 0: No wall
    Value 1: Wall
  6. Rename the Combo Overlay to "Walls"