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geoflow3d / gfp-building-reconstruction

Geoflow plugin for building LoD2 reconstruction from a point cloud
GNU Affero General Public License v3.0
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Ground detection inside footprints #20

Closed Ylannl closed 4 years ago

Ylannl commented 4 years ago

This will fix seemingly arbitrary planes getting assigned to:

  1. courtyards inside building footprints that are not present as a hole in the input polygon
  2. underground parts of the building (eg parking garage Markthal)

Idea for implementation:

  1. including the ground points inside and around the building
  2. fit a plane through the ground points
  3. include the ground plane in the graph-cut optimisation
  4. include the ground points in the heightfield used by the gc optimisation
  5. remove the faces that are labelled with the ground plane after the optimisation
balazsdukai commented 4 years ago

I think there is a large overlap with https://github.com/tudelft3d/underground-buildings-filtering/issues/3 . Would it solve the issue if the underground part was cut off from the footprint before going into geoflow?

But in case we do an underground-part-filtering prior geoflow, probably we won't identify all the cases (but most I think), so you still need to handle these somehow. Or they will simply end up in the bunch of reconstructed buildings that are "problematic".

Which makes me wonder if https://github.com/tudelft3d/underground-buildings-filtering/issues/3 is redundant.

Or, since we do the whole underground building classification anyways, maybe better to keep this task there, so you don't need to deal with it in the reconstruction?

In the classification we label these partially underground buildings, would the labeling help?

Ylannl commented 4 years ago

I believe the method I propose above gives a more elegant and robust solution than cutting or replacing the footprint prior to reconstruction. It will be more data-driven and less dependent on errors in the BAG/BGT polygons. That is if it all works as well as I expect it to...

I think I would first try to simply perform this for all the buildings. In that case no prior labelling is needed. In fact it would be easy to label the building if a part of the footprint was cut off.

Labelling the floating buildings would still be useful however. I don't see how I can do that in the reconstruction method.

Ylannl commented 4 years ago

This should be fixed now with 4842e5b