filters.hag

The Height Above Ground (HAG) filter takes as input a point cloud with a Classification dimension, with ground points assigned the classification label of 2 (per LAS specification). It returns a point cloud with a new dimension HeightAboveGround that contains the normalized height value.

The HAG filter works by iterating through all non-ground points, finding the nearest neighbor (in XY only) amongst the ground points, and computing the distance between the two Z values.

Example

{
  "pipeline":[
    "input.las",
    {
      "type":"filters.hag"
    },
    {
      "type":"filters.ferry",
      "dimensions":"HeightAboveGround = Z",
    },
    {
      "type":"writers.las",
      "filename":"output.las"
    }
  ]
}

Options

None