BAG data _ Indications on basement

Datasets BAG
6

Hi @mdg , I spotted a few things in your question that need some attention in my opinion.

  1. The attribute ground-0.0 was part of the previous version of the 3D BAG, which was replaced in March 2021. Here is the announcement of the new version on this forum: The new 3D BAG is released - BAG - Geoforum , and you might need to check the documentation to navigate the new data model Data Layers - 3D BAG
  2. There are buildings in the Netherlands below the mean sea level (0m), as noted above.
  3. In the new 3D BAG we modify the original building footprints (from the BAG), and remove the parts from the footprint that are underground. This process is not super accurate and if we chop off part of the footprint it does not guarantee that there is a basement. It can also be some error in the input data, error in the algorithm etc.
  4. At the moment we discard these underground parts, because they are not needed for anything. Thus in order to find out if a building has underground parts, you would need to calculate the geometric difference between the BAG and the 3D BAG footprints.
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