Add option to limit max triangle edge length

[zdila]

Describe the bug

Please add option to limit max triangle edge length. I am not sure if it should belong to filters.delaunay or to filters.faceraster.

Just for the reference - Whitebox Tools has this option - whitebox_tools -r=LidarDigitalSurfaceModel --max_triangle_edge_length=5 ....

System/installation information:

Linux bono 6.0.0-6-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.0.12-1 (2022-12-09) x86_64 GNU/Linux

pdal 2.3.0 (git-version: Release)

[hobu]

see #3928 3928

[abellgithub]

I don't think this is doing what you want. This filter creates a raster from an existing triangulation. The edge length is the edge length of the raster cell.

In general, there's no way to limit the edge length of a triangulation of points because points might simply be too far apart to meet the request. Perhaps the OP can refer to an existing algorithm?

[hobu]

ah, I was confused on what edgeLength mean

[zdila]

In the existing algorithm it is here: https://github.com/jblindsay/whitebox-tools/blob/e7fcdf3fc6fe71956833723b53afdf445b0608d1/whitebox-tools-app/src/tools/lidar_analysis/lidar_dsm.rs#L634

[abellgithub]

That's not a delaunay triangulation. You can't guarantee edge length with a delaunay triangulation.

[wonder-sk]

I think the idea was to make filters.faceraster optionally ignore triangles where the edge length > X when rasterizing triangles (rather than constraining triangle size in Delaunay triangulation)... The assumption is that triangles with long edge(s) would go across "holes" in point cloud data, and that would be a simple way of filtering them out.

[zdila]

Please reopen.

[hobu]

If you have a PR to implement this we will consider merging it. I'm not going to try again 😄