[GRASS-user] Trying to reclassify raster using non-linear functions in GRASS

[Pietro]

Hi Gabriel,

On Fri, Nov 8, 2013 at 1:54 AM, Gabriel Zorello Laporta
<gabriellaporta at gmail.com> wrote:
> I am using ArcInfo Workstation and Grid in order to to produce Gaussian
> functions of elevation from a DEM with minimum value at 800m, as follow:
>
> elev_x800 = elev90 - 800
> elev_x800sq = pow(elev_x800, 2)
> elev_x800sqn = -1 * elev_x800sq
> elev_x800sqnd = elev_x800sqn / 500000
> elev_x800exp = exp(elev_x800sqnd)
> elev_x800gaus = elev_x800exp * 0.000798
> elev_x800gi = (elev_x800gaus * -11330) + 10.044
>
>
> I was wondering how to apply that in GRASS (because I want to move towards
> Open Software). Can you help me?

You can use r.mapcalc:

r.mapcalc expression="elev_x800 = elev90 - 800"

You can see more info about raster algebra, here:

http://grass.osgeo.org/grass64/manuals/r.mapcalc.html

Have a nice day.

Pietro