[comp.graphics] CONTOUR plotting; the GRAFIC package

narayan@cs.iastate.edu (Pankaj Narayan) (02/19/90)

	I want some reference where I can find an algorithm for
	drawing CONTOURS.

	The basic method of drawing them should be quite easy, as in:

	pick a point (x,y)
	find  f(x,y)
	color the corresponding pixel with the appropriate color (depending
	    on the value of f(x,y)
	examine neighboring points in some order (say, all those to the
	   right hand side)
	whichever point has a value close to the previous f(x,y), move there
	 and color that pixel.
	etc.

	The problem is to generate a data set that is large enough to
	help me generate a fine-grained set of contours. Perhaps the book
	that has algorithms for generating contours will also have
	methods for generating contour sets.

	If anyone of you has worked with a package called 'GRAFIC' that is
	written in FORTRAN at MIT (I think), and has seen the contour
	generation in that and has some idea of what algorithm that
	package uses (also, how do they get the data set for the
	demo program ??), I'd love to hear from you.

	Please mail or post.

	Pankaj Narayan
	narayan@atanasoff.cs.iastate.edu