[GRASS5] NVIZ and raster masking

Paul Kelly paul-grass at stjohnspoint.co.uk
Mon Aug 30 15:02:46 EDT 2004

On Mon, 30 Aug 2004, Otto Dassau wrote:

> It creates masks with values 1 or 0 and works fine with modules like d.rast or r.mapcalc. Does this have changed? I realized that r.mask doesn't exist in GRASS 5.7 anymore, and using a 1/NoData map as Markus describes also works. What would be the correct way to mask subregions?
> 1/NULL or 1/0 ?

Null or 0 cells are masked. Cells that contain *any* other value 
(including 1) are not masked. It is really very versatile!

> 2) In this context I found out that i.smap doesn't support any of those MASKs described above. I always need to add a second step with r.mapcalc to calculate a masked version of the resulting map. But this is maybe sth. for the bugtracker ...

Yes that is a known bug that i.smap does not support MASKed or null cells. 
It really should be documented in the manpage if it is not already. There 
are comments in the source code that suggest it does but it is not 
implemented correctly and would require quite a lot of work to get it 
fixed up IIRC.


More information about the grass-dev mailing list