"Granularity" from Create Terrain from Point Cloud

Under Create Terrain From Point Cloud (InRoads SELECTseries 3), there is a TIN filter with Granularity option.

What is the definition of "Granularity" in this function?

As my understanding, Granularity: Fine should be less points being filtered (removed) for terrain creation. DTM should be more accurate and more triangles.

Granularity: Coarse should be more points being filtered (removed) for terrain creation. DTM should be less accurate and less triangles.

HOWEVER, the filter results are seems exactly opposite.

Fine...2,646,365 points remain

Coarse: 6,256,833 points remain

Any idea?

  • When it comes to this TIN filter, think of the "granularity" as how much the filter itself is letting through to keep information.  Imagine a materials sieve filter in which the coarse filters let alot more information through because it has a much larger size for things to get through.  The criteria in a coarse filter is much wider apart so more information gets through to remain in the sample point cloud than what is filtered out.  Then when you have a fine filter, you are blocking alot more information to make it through the filter to remain in the surface.  So alot less information actually gets through the filter to remain in the point cloud.  Only certain things are allowed to get through that filter because the values of the criteria are much tighter.  


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    Answer Verified By: Jing Jing