[GRASS-user] r.mapcalc and producing a max value map

____________________
C. Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: <www.public.asu.edu/~cmbarton>

On Jul 14, 2008, at 6:32 AM, <grass-user-request@lists.osgeo.org> wrote:

Date: Mon, 14 Jul 2008 15:22:03 +0200
From: Christian Schwartze <Christian.Schwartze@uni-jena.de>
Subject: [GRASS-user] (no subject)
To: grass-user@lists.osgeo.org
Message-ID: <1216041723.487b52fbc1998@webmail.uni-jena.de>
Content-Type: text/plain; charset=ISO-8859-1

Dear GRASS users,

could somebody help me to find some solution for the following task?
I have a raster map representing many distinct areas (MAP_1) and a second int
raster with specific values (MAP_2). The result map should contain the same
areas of MAP_1 but with the max MAP_2 value of each area as IDs. I tried some
approaches with r.mapcalc but I don't know how to code the region aspect of
MAP_1 into r.mapcalc.

  MAP_1 MAP_2 ---> MAP_MAX
  ----- ----- -------

  1111333332 5266723974 7777999995
  1113333222 1429784155 ---> 7779999555
  1113333322 4152763923 7779999955
  1111144442 4125718443 7777788885

Christian,

I think what you need is the following:

r.statistics base=map_1 cover=map_2 method=max output=map_max

Michael