GIS595/MEA792:
UAV/lidar Data Analytics

This is an unmaintained course material, please see current material at:

Basic workflows for importing lidar data to GRASS GIS

If you want to obtain a DEM/DSM in GRASS from .las point cloud use one of the following options:

  1. binning
    • Use r.in.lidar to create raster map using binning. Crude but fast.
    • Multiple tiles can be merged by r.patch after r.in.lidar (since they are raster maps)
  2. interpolating
    • Use v.in.lidar to create vector map with points (you can use -t and -b to not build topology and attribute table and speed up the process)
    • Multiple tiles can be merged by v.patch (since they are vector maps).
    • This you can interpolate using v.surf.rst.

If the projection of the .las file does not match your GRASS location use one of the following options:

  1. Use las2las before using r.in.lidar or v.in.lidar. The following example command is for reprojecting tiles in NAD83/North Carolina in feet (EPSG:2264) into NAD83/North Carolina in meters (EPSG:3358):
    las2las --a_srs=EPSG:2264 --t_srs=EPSG:3358 -i input_spf.las -o output_spm.las
    
  2. You can create a Location which matches the resolution of the las file and then v.in.lidar to import the points there and finally, go to the desired Location and use v.proj to re-project the data from the other Location.