The LIDAR_THIN command allows Lidar point clouds to be spatially thinned, either in 2D or 3D. A full Lidar point, with all attributes, is kept for each cell that has a point.The following parameters are supported by the command:
- FILENAME - filename or description of loaded Lidar layer(s) to spatially thin. This parameter can be listed more than once to specify multiple input files, like FILENAME="FILENAME_1" FILENAME="FILENAME_2". If no FILENAME is provided, all loaded Lidar layers will be thinned.
- LAYER_DESC - specifies the description to assign to the new point cloud layer. If not provided a default description will be assigned.
- GRID_BIN_SIZE - specifies the spacing that the data is thinned to as a multiple of the native spacing/resolution of the source Lidar point clouds. For example, GRID_BIN_SIZE=4 would create a new point cloud at 1/4th of the native spacing. To specify the spacing in ground distance, use the SPATIAL_RES_METERS parameter instead.
- SPATIAL_RES_METERS - specifies the spacing that the data is thinned to in meters.
- ELEV_DIST - specifies the spacing in the Z direction that the data is thinned to in meters. Only applies if THIN_ALG="3D" is used. If not provided, the ELEV_DIST will be the same as the 2D spacing (from GRID_BIN_SIZE or SPATIAL_RES_METERS).
- THIN_ALG - specifies the thinning algorithm that is used. The following values are supported:
- 3D (default): the Lidar point of median height is kept from each 3D cell (2D size from GRID_BIN_SIZE or SPATIAL_RES_METERS, height from ELEV_DIST)
- MIN: the Lidar point of minimum height is kept from each 2D cell
- MAX: the Lidar point of maximum height is kept from each 2D cell
- MED: the Lidar point of median height is kept from each 2D cell