On 06/10/14 17:31, Pietro wrote:
Il 06/ott/2014 17:04 "Moritz Lennert" <[email protected] <mailto:[email protected]>> ha scritto: > > On 06/10/14 16:14, Pietro wrote: >> >> On Mon, Oct 6, 2014 at 3:17 PM, Moritz Lennert >> <[email protected] <mailto:[email protected]>> wrote: >>> >>> On 06/10/14 14:54, Pietro wrote: >>>> >>>> >>>> Trying to circumvent the r.mapcalc min/max limit, >>> >>> >>> >>> Just out of curiosity: why don't you just use r.recode or r.rescale ? >> >> >> r.rescale was my first option, but it just reclassify in two >> categories 1 and 255. > > > r.rescale assumes that input is integer, so if you feed it values between 0 and 1 then yes, but using the NC data as example and feeding it the elevation data directly: > > r.rescale elevation out=elevation_0_255 to=0,255 > > gives the expected result. To make the example reproducible I've scaled the elevation map to have all the values between 0 and 1. So as you said r.rescale is not an option. >> I didn't thought about r.recode...but I think that easier combining r.info <http://r.info>. > > Why would you need r.info <http://r.info> for that ? Sorry I was in harry to catch the train... I was too succinct... I mean as you suggested combine r.mapcalc and r.info <http://r.info> to rescale... Another option is to modify r.rescale to work with CELL,FCELL, and DCELL. I don't see any particular reason to limit the module to the cell case... > Dividing by the max and then rescaling should give the same > result as rescaling from the original values... All you are > doing is dividing all values by a constant before rescaling. Yes, this was just an example using the north Carolina data set to make the problem reproducible... But it is true I can also multiply my map to 10000 and then use r.rescale. I think should work.
Or just use r.recode which is meant for FCELL and DCELL. A part from a small bug that made using -1.0:1.0:0:255 difficult (#2053), it works perfectly.
Moritz
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