[GRASSLIST:3869] Re: Combining maps

[Glynn Clements]

Alexandra Zamparas wrote:

> I am trying to combine two maps: one has subbasins with each subbasin
> being a separate category (1-270) and the other map is a soil texture
> map (1-12) of the same area. I am using the spearfish data. What I
> would like to do is to combine these two in such a way that the output
> shows the outlines of the subbasins and underneath I can see what
> soil types there are in each subbasin. Same thing maybe for the
> landuse map.
> 
> r.combine provides boolean options but here I would like to see the
> various categories of the underlying map in the outlines of the
> subbasins I got from r.watershed.

Set the subbasins map as a mask, e.g. with r.mask. The subbasins
should have a non-zero value while the rest of the map should be zero. 
Then, any operation which reads another map will read null (no data)
for the areas outside of the subbasins. You can use r.resample to
generate a (masked) copy of a map.

-- 
Glynn Clements <glynn.clements at virgin.net>