[GRASSLIST:165] Sum for an area

[Daniel Victoria]

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

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)?

Thanks
Daniel