I found that r.mask does not behave as I would expect and I would really appreciate some clarification.
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.”
I found that r.mask does not behave as I would expect and I would really appreciate some clarification.
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.
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 ? :))
> 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 ? :))
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 ? :))
