Milton Cezar Ribeiro wrote:
Dear all.
I am trying to work around with a problem of map size under Vista (>2G).
I was wondering if I use the command below I will get a raster
map with values integer and >=0.
    r.mapcalc "Dem.new=if(Dem>=0,int(Dem),null())"
If the original DEM is of type DCELL, you can reduce file sizes with
r.mapcalc "DEM.float = float(DEM)"
because one DCELL value needs 8 byte whereas both FCELL and CELL values need 4 bytes each. Converting from FCELL to CELL doesn't make a big difference, I even found that sometimes FCELL raster maps are higher compressed in GRASS than CELL raster maps.

I would rather try to keep decimal places for elevation maps, results are in my experience more accurate with floating point than with integer (e.g. 1m vertical resolution) maps (notwithstanding that a vertical resolution of say 0.1 micrometer is IMHO nonsense).

Just my .2c

Markus M

As my original map have values positive and negative, as well as
it is fload, my question is if are there a way of I force my output
map accept only integers>=0. By the way, is there a way
of I know if a map is float or integer?
bests milton
------------------------------------------------------------------------

_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user
_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

Reply via email to