[GRASSLIST:205] Re: Sum for an area

[Markus Neteler]

Hamish wrote:

>>>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?
>>    
>>
>
>r.univar too; any thoughts from the list on if r.univar should report
>sum in full instead of shortening to 1.23456e+07?
>  
>

To me a shortened value doesn't make much sense.

Markus