[GRASS-user] cutting issue (again): r.mapcalc vs. r.resample

[Rich Shepard]

On Mon, 25 Jan 2010, Tim Michelsen wrote:

> I while ago I asked how to cut a small map from a larger one using the
> region settings as boundary for the small map:
> http://n2.nabble.com/r-mapcalc-changes-color-table-td4072836.html#a4072836

> I tried this again:
> Approach 1: r.mapcalc
> Approach 2: r.resample

> Am I doing something wrong?

Tim,

   Looks like it.

   I asked for guidance on doing just what you need to do: cut out the
project area from a larger DEM.

   The approach that worked for me was described by Helmut Kudrnovsky:

   1) zoom to your area of interest of your larger region.

   2) v.in.region e.g. "v.in.region output=testarea", so the extent of your
   area of interest is defined by the vector "testarea"

   3) "g.region vect=testarea", by this  the region is set to your area of
   interest for analysis. "This region defines the geographic area in which
   all GRASS displays and raster analyses will be done."

   Works like a charm.

Rich