AlgorithmFilterXY

Filtering Out Points at Same X,Y

Interpolation of a raster surface requires that no two points have the same x and y coordinates (it causes problems mathematically). If two or more points are at the same x,y location, then all the points except the lowest point (i.e., with minimum z coordinate) must be non-ground. So those higher points can be classified and removed from the list of unclassified points.

1. for each x,y location in U₀ with two or points:
2. . . z_lowest = minimum z coordinate of the points at x,y
3. . . for each point P_j at x,y:
4. . . . . if z_j > z_lowest then
5. . . . . . . classify P_j as non-ground and remove it from U₀