[GRASSLIST:167] Re: Sum for an area

[Markus Neteler]

On Thu, Mar 16, 2006 at 10:37:49AM -0300, Daniel Victoria wrote:
> Hi all,
> 
> This is probably a very dumb question but I'm stuck... I need to
> calculate the total precipitation over a basin. I have the annual
> precip raster and the basin raster. So, I'm issuing the command
> 
> r.statistics base=sto_ica cover=ppt.81 at cru method=sum output=test
> 
> And I get:
> ERROR: This module currently only works for integer (CELL) maps
>

yes, an annoying problem...
 
> Of course I could easily convert the precip map (ppt.81) to integer
> but I'm afraid that, since it's a big area, this could result in some
> errors (sub-estimation in the final sum).
> 
> I'm sure there is another way to accomplish what I want, I just don't
> know how. Or, should I not worry about errors (sub-estimations)?
>

if you set a MASK for the basin, will
r.sum
do the job?

Markus