[GRASS-dev] r.mask: odd behavior?

[Veronica Andreo]

2017-11-19 22:08 GMT+01:00 Veronica Andreo <veroandreo at gmail.com>:

> Hi Markus,
>
> > The issue is the following: I apply a mask, then I do some processing, I
>> remove the mask and when I display the resulting map, all the pixels were
>> processed. I would expect that those pixels that I masked were treated as
>> NULL and not considered exactly as the message says:
>>
> >
>> > "All subsequent raster operations will be limited to the MASK area.
>> Removing
>> > or renaming raster map named 'MASK' will restore raster operations to
>> > normal."
>>
>> A MASK affects only reading raster data, not writing raster data.
>> Therefore r.mapcalc "test = 1" will always produce a map without NULL cells.
>>
>
> Got it! That r.mapcalc expression was not reading any map. If I do for
> example
>
> r.mapcalc expression="elev1=elevation + 1"
>
> and then remove the mask, it does work as I would have expected.
>
> IMHO, the message is confusing then... not "all" subsequent raster
> operations are limited to the mask, only if you read a map...
> What about a mask also for writing raster data in GRASS 8 ? :))
>

I have added it here: https://trac.osgeo.org/grass/wiki/Grass8Planning
Maybe someone else thinks this would be useful :)

Vero
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