[GRASS-user] Extrac values with r.mapcalc

GRASS GRASS user
1

Thanks Markus.

I did test with r.mapcalc novo_raster = if"(mi flat_map==0.0234)", but the map is not appropiate. I know the area of value (0.0234), but is not is equal in the novo_raster.

El 13/04/2011, a las 17:27, Markus Neteler escribió:

2011/4/13 Gaspar Reyes Póndigo <gos47@hotmail.com>:

Hello, Dear grass_user. My first forum participation in the grass_user list

email.

Welcome!

How to extract values of map raster with r.mapcalc? I need make new map

raster based on specific value of other raster.

Please take a look at the if() conditions:

http://grass.osgeo.org/grass64/manuals/html64_user/r.mapcalc.html

Therein is also a section EXAMPLES.

Markus

2

Hi Gaspar,

r.mapcalc “new.map = if(flat_map==0.0234,flat_map,null())” → if you want to preserve original values

or

r.mapcalc “new.map = if(flat_map==0.0234,1,null())” → if you prefer to assign a value of 1 to those values equal to 0.0234 in the original raster map

It should work.
Lluís

El dc 13 de 04 de 2011 a les 18:21 -0500, en/na Gaspar Reyes Póndigo va escriure:

Thanks Markus.

I did test with r.mapcalc novo_raster = if"(mi flat_map==0.0234)", but the map is not appropiate. I know the area of value (0.0234), but is not is equal in the novo_raster.

El 13/04/2011, a las 17:27, Markus Neteler escribió:

2011/4/13 Gaspar Reyes Póndigo <gos47@hotmail.com>:

Hello, Dear grass_user. My first forum participation in the grass_user list
email.

Welcome!

How to extract values of map raster with r.mapcalc? I need make new map
raster based on specific value of other raster.

Please take a look at the if() conditions:

http://grass.osgeo.org/grass64/manuals/html64_user/r.mapcalc.html

Therein is also a section EXAMPLES.

Markus

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