[GRASS-user] Get sums of raster values based on the categories of an overlay raster

[Moritz Lennert]

On 26/11/13 16:28, Johannes Radinger wrote:
> Hi,
>
> I'd like to calculate the sum of all raster values that belong to a
> certain group. This spatially organized group is also indicated by an
> overlay raster (same resolution). Finally I want to assign these sums to
> a new raster. That might sound slightly complicated but here an example:
>
> Asume following initial raster map A with random values like:
>
> 1-2-1-1-3-4-3-4-2-5-2-3
>
> and an overlay raster indicating 3 groups:
>
> 1-1-1-1-2-2-2-2-3-3-3-3
>
> the sums for the groups are:
> group 1 = 5
> group 2 = 14
> group 3= 12
>
> so the final raster would be:
>
> 5-5-5-5-14-14-14-14-12-12-12-12
>
> How can such a task be achieved in GRASS (7)?
> Any ideas?

r.statistics ?

Moritz