The red lines are the Voronoi vertices and the blue lines form the Delaunay triangulation. Click anywhere in the applet window to add a point.
Reference: Weatherill N P, "A Method For Generating Irregular Computational Grids In Multiply Connected Planar Domains", International Journal Of Numerial Methods in Fluids, Volume 8, 1988, pages 181-197
Documentation Outlines the Voronoi algorithm based on the above reference (postscript file).
Java source code (written in Visual J++ 1.0)
Windows 95/98/NT application An improved version of the Voronoi demo program for Windows 95 or later.
Windows source code (written in Delphi 2.0)
Fortran source code I wrote this years ago and have forgotten which version of Fortran this compiles with.
Contour plotting program This uses the Voronoi algorithm to triangulate a set of user-specified points. Values associated with the points are linearly interpolated within the triangles to generate the contours.