[GRASS-user] Some issues with r.mapcalc

[achim]

Hi,

you can use another if-clause,to test, if the other map is null using
"isnull(railroads)" eg.

Another way could be to use ||| (3x"|") to handle null-values
(for that see:
http://grass.itc.it/grass64/manuals/html64_user/r.mapcalc.html
section "sull support").

achim


Fulvio Mastrogiovanni schrieb:
> Hi everyone,
> 
> I hope you can help me in solving this issue. Basically, what I want to do is to
> create a new raster map whose cells are simply given by the "or" of other two
> maps (possibly for specific categories), as follows:
> 
> r.mapcalc test=if(vegcover==1 || railroads==1)
> 
> However, maps like railroads are null() when not equal to 1. The resulting map
> "test" is null() wherever cells in railroads are null(), therefore making
> null() also cells where vegcover is 1.
> 
> How can I solve this issue?
> 
> Thanks!
> 
> Fulvio
> 
>