[net.graphics] Contour Algorithm wanted

mrs@briar.UUCP (Stephen Covenant) (08/04/86)

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

mike@mipos3.UUCP (Michael Bruck) (08/07/86)

I would also be very interested in a contouring program.

	--Michael Bruck
	  {decwrl,hplabs,amdcad}!intelca!mipos3!mike

mrw@homxb.UUCP (M.WHITNEY) (08/10/86)

To whom it may concern:
                      An outstanding source of contour algorithms
and TONS of other goodies is the _Collected_Algorithms_of_the_ACM_,
which can be found in most college libraries.  I used one called 
GCONTR which did an outstanding job on my thesis graphs.  It is 
written in vanilla FORTRAN-IV, and has many options regarding the
machine dependent stuff.  You will need to adapt your particular
graphics system calls to the ones they use in the program, but it is
really not too difficult.  I also adapted it to run under Microsoft
FORTRAN with a couple of short assembly code programs.  There are other
routines in the Algorithms besides GCONTR that do contour plotting, in-
cluding ones that can be used to generate contour maps with irregularly
spaced data points.

           Ken Becker   hotlv!kab

The opionions expressed above are mine only, and not those of my employer.