A user asked us how to calculate AGL height (sometimes also called nDSM for buildings or CHM for trees) after DEM extraction by CSF (https://www.researchgate.net/post/Dose_ ... AGL_height). We give a possible solution.
Thank you for using CSF. Currently, we don't have plan to compute AGL height. But I can give two solutions instead.
1. CSF is also integrated in point cloud magic (http://lidar.radi.ac.cn/item_detail.php ... =soft&id=2), and this freeware can compute AGL height. But it has only chinese version.
2. If you use CSF in Cloudcompare, the following steps may work.
a) Get ground points (GPs) and off-ground points (OGPs) by CSF;
b) Compute distance between OGPs and GPs by "Tools->Distances->Cloud/Cloud dist.";
c) GPs should be "reference" points, and OGPs should be "compared" points;
d) In Tab of "general parameters", "split X,Y and Z components" should be selected, because only height (Z component) is needed.
e) In Tab of "local modeling", a local model should be chosen, because there are holes in GPs;
f) After distances computation, select off-ground points and switch "Active" scalar field to "C2C absolute distances (Z)" in the "Properties" window;
g) Convert scalar field of distance (Z) into coordinate (Z) by "Edit->Scalar fields->Set SF as coordinate(s)", and now you have point clouds with AGL height.