It looks like for the 2nd calculation, your computational region is set to extents of 0W - 1E, 0S - 1N, with a resolution of 1.
So r.mapcalc is only operating on a single 1x1 cell that is outside the area of your raster map. Michael ____________________ C. Michael Barton Director, Center for Social Dynamics & Complexity Professor of Anthropology, School of Human Evolution & Social Change Arizona State University voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC) fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC) www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu On Sep 27, 2011, at 11:50 PM, <grass-user-requ...@lists.osgeo.org> <grass-user-requ...@lists.osgeo.org> wrote: > Date: Mon, 26 Sep 2011 23:19:11 -0400 > From: Jim Mochel <jim.mochel.hi...@gmail.com> > Subject: [GRASS-user] r.mapcalc appears to have changed behavior > To: grass-user@lists.osgeo.org > Message-ID: > <CAE=Y9-Q7tFZ=cJ4TC6nceYA5B=r9e7rrwzbvff_fybmntep...@mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > I had made a number of scripts that worked fine in the 6.4.0 build 6 but > appear to have problems with the same code in later revisions: > > The method used to take about 6-8 secs and produce about what you would > expect on the screen. Now the same calculation takes 0 seconds the file is > radically changed. See the before and after below. > > Any help would be greatly appreciated. > Thanks > Jim Mochel > > r.mapcalc na_dem_sub_20 = na_dem_input - 20 > > > +----------------------------------------------------------------------------+ > | Layer: na_dem Date: Sat Sep 24 17:37:59 2011 > | > | Mapset: PERMANENT Login of Creator: jmochel > | > | Location: wgs84 > | > | DataBase: /home/jmochel/grassdata > | > | Title: ( na_dem ) > | > | Timestamp: none > | > |----------------------------------------------------------------------------| > | > | > | Type of Map: raster Number of Categories: 65535 > | > | Data Type: CELL > | > | Rows: 8384 > | > | Columns: 9102 > | > | Total Cells: 76311168 > | > | Projection: x,y > | > | N: 4384500 S: -3999500 Res: 1000 > | > | E: 4639500 W: -4462500 Res: 1000 > | > | Range of data: min = 0 max = 65535 > | > | > | > | Data Description: > | > | generated by r.in.gdal > | > | > | > | Comments: > | > | r.in.gdal input="/home/jmochel/gis/raw-data/hydo1k/na_dem.bil" outpu\ > | > | t="na_dem" > | > | > | > +----------------------------------------------------------------------------+ > > > r.info map=na_dem_sub_20 > > +----------------------------------------------------------------------------+ > | Layer: na_dem_sub_20 Date: Mon Sep 26 23:06:03 2011 > | > | Mapset: PERMANENT Login of Creator: jmochel > | > | Location: wgs84 > | > | DataBase: /home/jmochel/grassdata > | > | Title: ( na_dem_sub_20 ) > | > | Timestamp: none > | > |----------------------------------------------------------------------------| > | > | > | Type of Map: raster Number of Categories: 610 > | > | Data Type: CELL > | > | Rows: 1 > | > | Columns: 1 > | > | Total Cells: 1 > | > | Projection: x,y > | > | N: 1 S: 0 Res: 1 > | > | E: 1 W: 0 Res: 1 > | > | Range of data: min = 610 max = 610 > | > | > | > | Data Description: > | > | generated by r.mapcalc > | > | > | > | Comments: > | > | na_dem_input@PERMANENT - 20 > | > | > | > +----------------------------------------------------------------------------+ _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user