[GRASS-dev] r.mapcalc 32-bit ceiling

Andy Wickert andrewwickert at gmail.com
Thu Nov 24 22:31:50 EST 2011

Hi Grass-dev,

I ran into an unexpected issue (to me, at least) with r.mapcalc:
I was multiplying and dividing by some pretty big scalars, and one of
those was greater than a 32-bit signed value (so >2**31). What mapcalc
did was to reduce that value to 2**31 and carry on with operations.
There was no warning, and I didn't find any information about this on
the r.mapcalc help page, so I just wanted to alert (or possibly
remind) the list that this exists and note that (as a non-developer)
it took me a while to figure out that this was a problem. If there is
an easy way to throw an error instead of silently hitting a ceiling,
or this would be important enough to put on the manual webpage, I
think it would be helpful, and certainly would have saved me a ton of

Thanks, and happy Thanksgiving to those in the USA!


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