[GRASS-user] categories in raster map

[Moritz Lennert]

On 26/02/09 11:47, FAROUX STEPHANIE wrote:
> Hello,
> I see the function r.cats which allows to read categories of a raster 
> map, but how can i define these attributes? Should i pass by a vector 
> map? In the database menu, it doesn't seem possible to add a table for a 
> raster map.

Raster maps have categories and labels. Categories have to be numerical, 
labels can be anything. Each pixel needs to have a category value (or 
NULL) and optionally you can have one (and only one) label per category 
value.

BTW, r.cats is now replaced by r.category.

If you want to link a cell with many attributes, you will have to use 
vector grids (v.mkgrid or r.to.vect as you suggestà).

Moritz