Ron Parker wrote:
> 
> On Tue, 05 Mar 2002 09:59:02 +0200, Vahur Krouverk wrote:
> > Mark Wagner wrote:
> >>
> >> I'm looking for a program that will take a heightfield image that I've
> >> created and turn it into a contour map.  I've found GRASS, but it seems a
> >> bit overkill for the job, and it's a 17 MB download.
> >>
> > Won't POV-Ray be suitable? if you render heightfield orthographically
> > from top and create texture map accordingly to height?
> 
> That technique has a tendency to make fat contour lines where the slope is
> gentle.

Yes, if one wants to have nice contour lines. But I believe, that by
using derivative of slope it could be possible to make line width more
or less constant. For calculating derivative normal of height field
could be suitable and with shader its implementation could be quite easy
(probably easier than with slope map, at least for me). Lack of
transformation to/from screen coordinates probably will be limiting
factor here, but with some adjusting of input parameters it could be
hacked around. Unfortunately I don't have time right now, but I do feel
challenge here and on next free moment try to implement it.

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