LAStools Classify

Class tab of the control window for the point cloud.

This strings together three LAStools programs.  All have a restrictive license, and you should carefully evaluate if you are allowed to use the free version.  This is included in MICRODEM solely for educational purposes, and to expose people to LAStools.

Without licensing, large data sets will have anomalies introduced into the data, and you will be warned.  You should read the documentation of each of these modules, to understand the parameters, but a quick run through with the defaults will show how this processing runs.

• lasground: finds the ground returns, which define a continuous surface at the bottom of the point cloud, excluding low noise.  This has several parameters, most importantly a step size which affects how buildings will be excluded, and a bulge parameter which affects how much local variation is allowed in the surface created by a TIN of the ground points.  These two parameters are similar to those used in mcc-lidar (which is completely free, but slow). Intermdiate files are written to MICRODEM's temporary folder.
• lasheight: computes the height of each point above the terrain surface.  Intermdiate files written to MICRODEM's temporary folder.  Should not require any parameters.
• lasclassify: looks for regions above the ground with planar orientation (roofs) or rough surface (vegetation).   It has parameters defining planar and rough; if you want to change the defaults, you will have to experiment, and read the documentation.  The best values depend on the density of the point cloud, and the characteristics of the terrain.

Last revised 10/31/2019