[GRASS-user] newbie category question..

[cgnicholas at alamedanet.net]

Hi -

I'm trying to do something I thought was fairly simple, but eludes me...

I'm trying to find the average elevation of polygons.  I used
gdal_rasterize to make a layer, which does indeed have unique categories,
and values, for each building.

I'm trying to use this layer against a DEM, and on a per-polygon basis,
get the min/max of the DEM ... I was thinking that somehow I might use
r.statistics, but....not so straightforward, apparently.

thanks in advance for any suggestions!

Chris

p.s. - it would sure be nice if I could make key/value pairs within
mapcalc; that way I could read a category from one layer, make a key, and
fetch it anywhere within mapcalc...