geompack, a FORTRAN77 code which computes the Delaunay triangulation of a set of points in the plane, by Barry Joe.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
geompack is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version.
geometry, a FORTRAN77 library which performs geometric calculations in 2, 3 and N dimensional space.
triangulation, a FORTRAN77 library which performs various operations on order 3 (linear) or order 6 (quadratic) triangulations.
Original FORTRAN77 version by Barry Joe; This version by John Burkardt.