[GRASS-dev] Overflow warning in r.mapcalc calculation

Paulo van Breugel p.vanbreugel at gmail.com
Wed May 15 04:34:02 PDT 2013


Hi,

I am having trouble with the following computation, which gives me an 
overflow warning ("WARNING: Overflow occured in the calculation").

r.mapcalc "A = if(B==0, (round(C/0.0001)-1175699902)/(3007966667-1175699902) *100.0, 1)" --overwrite


whereby C is a map with values between 1 and 31000. It seems to be 
related to the size of the numbers (no warning if I divide C by 0.001), 
but I am not clear what limit I am hitting here or how to avoid this.

The warning does not stop the calculation, and the resulting map seems 
to be correct. However, I rather avoid this warning, also because the 
warning message causes problems when running in batch from within R.

I am running GRASS 7.0 on Ubuntu 13.04 64 bit.


Best

Paulo



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