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Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!ai-lab!sundar
From: sundar@wheaties.ai.mit.edu (Sundar Narasimhan)
Newsgroups: comp.graphics,sci.math
Subject: reference to contour plotting algorithm wanted.
Keywords: contour plots, vision, 3d-plotting
Message-ID: <717@special-k.ai.mit.edu>
Date: 2 Mar 89 00:21:44 GMT
Distribution: na
Organization: MIT AI Lab, Cambridge, MA
Lines: 16

Hi: I have a matrix of numbers (a discrete sampling of an underlying 
continuous space) that I'd like to produce a contour plot from. I'd like the
plot to do subpixel calculations (i.e. I dont want lines Manhattan routed).

Does anyone have a reference to algorithms that will do this? (I tried the 
usual hacks of modifying something like Breshenham's line drawing algorithm 
and a thresholding algorithm (i.e. you threshold above a certain height and 
then compute the boundary of the resulting regions for all heights given by
the contour quantization step) but they don't quite work).

-Sundar
(reply to sundar@wheaties.ai.mit.edu -- I'll summarize if there is interest)

PS: Note that I DO NOT have equations to describe the surface. If I did, I 
could probably use macsyma's contour plotting option. (BTW, does anyone know
how the algorithm for macsyma's contour plotting works?)