[GRASS-user] Fill holes with an area bigger of a specific value in a raster coverage

[Jorge Arevalo]

Hello Markus,


On Tue, Apr 29, 2014 at 10:07 PM, Markus Neteler <neteler at osgeo.org> wrote:

> On Tue, Apr 29, 2014 at 6:48 PM, Jorge Arevalo
> <jorgearevalo at libregis.org> wrote:
> > I want to fill some areas of a raster coverage with a value of my choice.
> > Those areas now contain NODATA values. So, they look like holes in my
> > coverage.
>
> If you want to set all NODATA area to the same value, then use r.null
> with null=yourvalue:
>
> http://grass.osgeo.org/grass70/manuals/r.null.html#examples
>
>
Yep, we already solved that. But thanks!



>
> > I know I could use r.clump function , but I don't know how to specify the
> > maximum area. Because if a hole is bigger than that area, I don't want to
> > consider it as hole. Is that even possible with GRASS?
>
> You could assign all NODATA areas a specific, yet unused value (see above).
> Then extract this value with r.mapcalc (if condition) and extract from
> the resulting map only the smaller areas with
>
> http://grass.osgeo.org/grass70/manuals/r.reclass.area.html
>
> Then merge them back with r.patch into the original maps in order to
> create the final map.
>
> Maybe there are other possibilities, too.
>
> Markus
>


Sounds like a good plan. We will try that way. Many thanks!!



-- 
Jorge Arevalo
Freelance developer

http://about.me/jorgeas80
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