filters.smrf

Filter ground returns using the Simple Morphological Filter (SMRF) approach outlined in [Pingel2013].

[Pingel2013]Pingel, T.J., Clarke, K.C., McBride, W.A., 2013. An improved simple morphological filter for the terrain classification of airborne LIDAR data. ISPRS J. Photogramm. Remote Sens. 77, 21–30.

Example

The sample pipeline below uses filters.smrf to segment ground and non-ground returns, writing only the ground returns to the output file.

{
  "pipeline":[
    "input.las",
    {
      "type":"filters.smrf"
    },
    {
      "type":"filters.range",
      "limits":"Classification[2:2]"
    },
    "output.laz"
  ]
}

Options

cell
Cell size. [Default: 1.0]
cut
Cut net size (cut=0 skips the net cutting step). [Default: 0.0]
outdir
Optional output directory for debugging intermediate rasters.
scalar
Elevation scalar. [Default: 1.25]
slope
Slope (rise over run). [Default: 0.15]
threshold
Elevation threshold. [Default: 0.5]
window
Max window size. [Default: 18.0]