I understand how vegetation could be removed, but buildings? How is that accomplished?
https://desktop.arcgis.com/en/arcmap/latest/manage-data/las-...
There will be a different algorithm for each feature class. For example, points that are part of a building might be identified by finding groups of points that form a very flat surface. ML models can also do this based on training data.
https://pro.arcgis.com/en/pro-app/latest/tool-reference/3d-a...
The final digital elevation model (DEM) is then just taking the "Ground" class from the classified point cloud and using them to triangulate a surface. This differs from a digital surface model (DSM), which will triangulate a surface based on ground+building+vegetation points.
It the Scotland we have heather that can coat hills but I’m not sure that you’d be able to tell the difference between that and a forest canopy to assume a height and then subtract. Maybe there’s more than the point cloud to work with.
With this information, you can filter the point cloud to only include points from the final return, which is likely to be the ground/a solid surface unless the vegetation is very dense.
Wasn't this also how the cities in the Amazon were discovered as well? These maps are fascinating. I can see ancient structures everywhere! Then again I'm not a trained archeologist.
schobi•8mo ago
The description confused me, as it describes the use of a real Lidar measurements to detect "change" in the terrain. But certainly, it can't be a temporal change before and after... to detect medieval settings in the data. Is the area still changing differentlybetween scans over multi year's? I don't think so.
I think this is visualization code highlighting natural VS. human train structures, at known locations of old settlements? Showing different approaches on how to visualize the man-made heights in the terrain.
But still, I'm lost how this could help finding new ones..
folli•8mo ago
See also here for an in-depth discussion on the potential use of such data: https://www.mdpi.com/2072-4292/15/6/1569
How do you suggest to change the description to make it less confusing?
folli•8mo ago
Of course, nothing so exciting to be discovered in Switzerland anymore ;)