Easy GRASS 5 question

[bob at math.umn.edu]

I'm trying to understand how to use GRASS as a read/write mapping 
utility.  The challenge for me is to learn what to do in order to 
read a pixel from a map layer, process it in some way, and then 
write it back out with a new value to the same map layer.  The on-line
docs have not yielded the dark secret of this relatively low-level
operation set.  Could somebody point me in the right direction?  Or
should I start looking at the source code for some related commands?

Thanks.  BTW, tangent now compiles, and thanks.

Adios,
Chris
-- 
C.S. Cornuelle 
School of Mathematics/MCIM, University of Minnesota
206 Church St. SE, Minneapolis, MN 55455
(612) 626-8930v, (612) 624-2333f, bob at math.umn.edu
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