[GRASS-user] Re: How to rescale an aspect map

[Moritz Lennert]

On 13/02/12 08:31, leonidas wrote:
> I need the most suitable areas (with SE aspect) to have the value of 255 and
> the unsuitable (North aspect) to have the value of 0. Grass returns N=90 and
> SE=315 and flat=0.
> So the minimum value of aspect raster is flat areas and the max is areas
> with 359 degrees of east.
> I should set North as the minimum value and SE as the max value (most
> suitable areas).
> I should rescale the raster because I need to include it in an AHP method.
> All rasters will be rescaled in a common 0-255 scale.


Try r.recode with rules like this:

90:315:0:255
315:360:255:170
1:90:170:0
0:YourValueForFlatAreas

Moritz