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On 21/06/2019 15:18, Stefan Blumentrath
wrote:
Ah, OK. Got that wrong, sorry. I don`t think holes have an area (but I may be wrong).... So you might have to add a centroid first? https://grass.osgeo.org/grass76/manuals/v.centroids.htmlCheers Stefan -----Original Message----- From: grass-user <[email protected]> On Behalf Of Robert Nuske Sent: fredag 21. juni 2019 13:49 To: grass-user <[email protected]> Subject: [GRASS-user] Fwd: Re: remove small islands from vector areas -------- Weitergeleitete Nachricht -------- Betreff: Re: [GRASS-user] remove small islands from vector areas Datum: Fri, 21 Jun 2019 13:47:52 +0200 Von: Robert Nuske <[email protected]> An: Stefan Blumentrath <[email protected]> Hi Stefan, as far as I understood does rmarea that remove small areas but not islands (holes) within areas. At least i didn't find a way to remove islands with v.clean.
When you say "remove islands" do you mean to "fill" small holes, and make them part of the surrounding polygon? If so, then this the procedure works: First buffer the original polygon by some distance "dist" that is big enough to cover what you consider "small". Then buffer again by "-dist". The small holes get filled on the first buffer, and the original polygons are restored without those holes with the negative distance by the second buffer.
thanks robert Am 21.06.19 um 13:06 schrieb Stefan Blumentrath:Hi Robert, Did you have a look at v.clean: https://grass.osgeo.org/grass77/manuals/v.clean.html with tool=rmarea > Cheers Stefan -----Original Message----- From: grass-user <[email protected]> On Behalf Of Robert Nuske Sent: fredag 21. juni 2019 12:33 To: grass-user <[email protected]> Subject: [GRASS-user] remove small islands from vector areas Dear Listers, sorry, it's me again. I want to remove islands smaller than a certain threshold from my vector map or if that is not possible all islands. I found some trick on an old manual page of v.extract. But this does not work anymore. Is there a new trick? thnaks robert _______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user_______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user -- Micha Silver Ben Gurion Univ. Sde Boker, Remote Sensing Lab cell: +972-523-665918 |
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