Re: [GRASS-user] log(0)-error in r.mapcalculator

2012-11-09 Thread Patrick S.
Thank you so much, Markus! That was the missing hint and it works now! However, I just went through the documentation, which says: /F/ means that the functions always results in a floating point value and Function log has F. This is somehow misleading and rather should be an *. Can I correct

Re: [GRASS-user] log(0)-error in r.mapcalculator

2012-11-09 Thread Markus Metz
On Fri, Nov 9, 2012 at 9:27 AM, Patrick S. patrick_...@gmx.ch wrote: Thank you so much, Markus! That was the missing hint and it works now! However, I just went through the documentation, which says: F means that the functions always results in a floating point value and Function log has F.

Re: [GRASS-user] log(0)-error in r.mapcalculator

2012-11-09 Thread Patrick S.
Markus, I understand your arguments, but A is the slope of r.slope.aspect and has floating point values as input for the formula. I just created a testcase to be able to report on the behavior in detail. As you can see below the results are truncated to integer as soon as I add a term to A

Re: [GRASS-user] log(0)-error in r.mapcalculator

2012-11-09 Thread Glynn Clements
Patrick S. wrote: ###Testcase2: formula= log(((A+1)/100)/(1-(A+1/100))) Note that (A+1/100) = A+(1/100) = A as 1/100 will use integer division. -- Glynn Clements gl...@gclements.plus.com ___ grass-user mailing list

[GRASS-user] log(0)-error in r.mapcalculator

2012-11-08 Thread Patrick S.
Dear List, I keep getting a log(0) error in r.mapcalculator, even if I enlarge the data. This seems to be a bug as I controlled the same data with R and get (non-infinity) values. Does r.mapcalculator eventually truncate the results of formulas to some integer values? logit-expression:

Re: [GRASS-user] log(0)-error in r.mapcalculator

2012-11-08 Thread Markus Metz
On Thu, Nov 8, 2012 at 10:50 AM, Patrick S. patrick_...@gmx.ch wrote: Dear List, I keep getting a log(0) error in r.mapcalculator, even if I enlarge the data. This seems to be a bug as I controlled the same data with R and get (non-infinity) values. Does r.mapcalculator eventually truncate