🚀 go-pugleaf

I  am looking for a public domain contour routine, preferably written in
C, but one written in Fortran is acceptable.  The  actual  code,  though
helpful,  is  not as important as a description of the actual algorithm.
The data to be contoured is on  a  non-uniform  rectangular  grid
{z  =  f(x,y)},  labels for the contour levels are not required, crowded 
lines need not be eliminated, BUT the algorithm must be FAST.

A  more  sophisticated  algorithm  which  removes   the   aforementioned
restrictions  would  be useful for future enhancements;namely, plots and
smooths irregularly distributed data, labels the contours and eliminates
crowding of contour lines.


Thanks in advance,

Mark R. Simpson
Philips Laboratories
Briarcliff Manor, NY