delaunay

Delaunay triangulation subdivides a set of 2D points into sets of three points such that no other point in the original set lies within the circumcircle of the triangle that these three points define. It is implemented in gnuplot as a filter operation that replaces the input set of points with a list of triangles in the format expected by plot style "with polygons". This filter is used as a first step in finding concave hulls using χ-shapes (see concavehull). It may also be applied explicitly to a projection of a set of 3D points onto the xy plane in order to create a tessellated 3D surface. See delaunay.dem

EXPERIMENTAL (implementation details may change in a future release). Present only if your copy of gnuplot was configured --enable-chi-shapes.

2D example

     plot POINTS using 1:2 delaunay with polygons fillstyle empty

3D example

     set pm3d border lc "black" lw 2
     splot 'hemisphere.dat' using 1:2:3 delaunay with polygons