Decimate point clouds to produce smaller LAS files.

• Decimation options are available in the batch file.
  1. "fiters.decimation" will save every nth point.
  2. "filters.voxelcenternearestneighbor" will save the nearest neighbor to the voxel center.
  3. "filters.voxelcentroidnearestneighbor" will save the nearest neighbor to the points' centroid.
  4. "filters.sample" will perform Poisson sampling to determine which points to save.