[GRASSLIST:2149] Re: r.reclass: how to reclass only part of thecategories

[Michel Wurtz]

Markus Neteler wrote:
> 
> On Fri, Jul 20, 2001 at 12:19:04PM +0200, mlennert at club.worldonline.be wrote:
> > Hello,
> >
> > I've downloaded some GLOBE DEM files, and I would like to use them in nviz.
> > The problem is that some areas (such as the polders in Holland) have values
> > around 65500, making it difficult to use the files in nviz due to the extreme
> > differences in values. I would therefore like to reclass them in order to give
> > them all a value of -1.
[...]
>  Moritz,
> 
> the value "65500" look as if the data are not correctly imported (see other
> comment from Roger). Did you use

It looks like a 16 bits negative number (0 is 65536, and 65500 is -36)
traited like an unsigned integer (which is normal for a category file,
but not for a DEM, especially in polders !)

with r.mapcalc, try : output = if(input < 32767, input, input-65536)

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Michel WURTZ - DIG - Maison de la télédétection
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