Computes the envelope of a set of points, which represents the area occupied by this points. A nearest neighbours approach is used to generate a concave or convex hull.
This is based on the works of Moreira and Santos 2007.
Adriano Moreira and Maribel Yasmina Santos (2007): CONCAVE HULL: A K-NEAREST NEIGHBOURS APPROACH FOR THE COMPUTATION OF THE REGION OCCUPIED BY A SET OF POINTS. GRAPP 2007 - International Conference on Computer Graphics Theory and Applications, pp. 61-68 moreira_and_santos_2007