[GRASS-user] r.mapcalc r.mapcalculator question

[Dr. Manfred Redslob]

Am Dienstag, den 15.06.2010, 06:39 -0700 schrieb varunvarma:
> Hi, I am a new user to GRASS and have run into a problem while processing
> rasters
> 
> I have 2 raster files (TIFFs) which I have loaded with GRASS in QGIS 1.0.2
> Kore. The rasters contain values of 0 and 1 and represent 2 time steps. What
> I wanted to do is either a simple addition of the 2 rasters or apply an OR
> operator between them. For this I used the r.mapcalc and r.mapcalculator
> tool. However, the cell size of the resulting raster is increased from 250m
> to 2500m which leads to loss of fine scale information.
> 
> Does anyone know why this is happening and what I could do to maintain the
> fine scale information?
> 
> Thank you

Hi however,

please check the actual resolution with g.region -p. Is the result
res=2500? If so, set region with g.region -ap res=250 or with g.region
rast=inputrasterfile. You can controll it again with  g.region -p. After
this settings run r.mapcalc again.

Regards,

Manfred