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

[Paulo van Breugel]

On November 20, 2017 11:45:57 AM Veronica Andreo <veroandreo at gmail.com> wrote:

> 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 :)

+1

>
> Vero
>
>
>
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