raster analysis using real locations? deficiency in mapcalc??

[Simon Cox]

Happy New Year everyone.

I want to manipulate a raster map layer where I
apply a polynomial transformation, in which the
coefficients of the polynomial are a (simple) function
of real location.  r.mapcalc only appears to know about
relative locations (using the neighbourhood operator).
I can imagine a gruesome technique involving r.stats
and some awk scripts, but there must be a better way.
Can anyone make a suggestion?

Simon Cox
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      __  L     Dr Simon Cox			
   ,~'  L_|\    VIEPS Department of Earth Sciences, 
,-'         \   Monash University, Clayton Vic 3168        
(            \  Australia
\    ___     /          Phone +61 3 905 5762
 L,~'   "\_x/           Fax   +61 3 905 5062
           u    simon at artemis.earth.monash.edu.au
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