Hard Surface Classification

The Hard Surface Routine is based off a planar fit algorithm, which is quite different than the traditional ground classification algorithm traditionally used for airborne LIDAR data. The hard surface routine will classify the dominant, median surface points. This provides an alternative to the traditional ground classification routine. The result is usually better performance on paved surfaces. You may need to draw polygons for paved areas to be able to classify terrain using Ground and paved areas using the Hard surface routine.

Classify Hard Surface Parameters

Classify Hard Surface Parameters


  • Plane Tolerance – Goodness of fit for the dataset
  • Max Terrian – max slope of triangle within the plane
  • Iteration Angle – the iteration angle is the angle between the triangle plane and a line connecting the potential point with the closest triangle vertex
  • Minimum Detail – Minimum Plane Size
  • Minimum triangle – Classification Limit

 Ground vs Hard Surface

Ground Hard Surface
  • Classifies local lowest points
  • Right result in terrain
  • Too low on asphalt
  • Cuts curb stones
  • Requires that you eliminate low points with other routines
  • Classifies median surface
  • Right result on asphalt
  • Keeps curb stones better
  • Does not require elimination of low points


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