[GRASS-user] Remove islands with v.extract problem (again)

[S. Koukoulas (listes)]

I don't know how your file looks like, but one of the following should work,

try
v.clean and remove small areas
or
make the internal islands polygons, and using the same attributes (add
them), use v.dissolve to get rid of internal polygons.

regards,
sotiris

On 06/12/2014 12:35 PM, Blumentrath, Stefan wrote:
>
> Hi,
>
>  
>
> I am trying to remove islands (here also in the topological sense)
> from a set of lake polygons.
>
>  
>
> The polygon layer contains only the water bodies (means islands within
> the lakes have no category).
>
>  
>
> I tryed v.extract -d as well as v.extract list/cats=1-99999999 both in
> GRASS 6 and 7 (on Ubuntu 12.04 LTS).
>
>  
>
> In all tests the layer did not get modified as expected and islands
> were still present.
>
>  
>
> This topic has been (repeatedly) discussed earlier. But the proposed
> solution (also in the manual of v.extract) did not work for others as
> well (quite some time ago):
>
> http://lists.osgeo.org/pipermail/grass-user/2006-January/032016.html
>
>  
>
> I am wondering what the problem might be?
>
> Any idea? I can provide sample data if that might help...
>
>  
>
> I am now using ST_ExteriorRing from PostGIS
> (http://postgis.net/docs/manual-2.1/ST_ExteriorRing.html) to achieve
> what I want, but it would be nice to have a GRASS solution... 
>
>  
>
> Cheers
>
> Stefan
>
>  
>
>
>
> _______________________________________________
> grass-user mailing list
> grass-user at lists.osgeo.org
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