[GRASS-user] how to select island polygons with grass

[Markus Neteler]

On Wed, Jun 25, 2008 at 3:46 PM,  <Christian.Strobl at dlr.de> wrote:
>
> hi all,
> principally an easy question but i have spent a few hours with google
> and found nothing. is there a possibilty with grass to select island
> polygons from a grass vector map, for example with arcinfo it was very
> easy
>
> Pseudocode: select Polygons from polygonLayer where leftPolygon =
> rightPolygon

With v.to.db you can select left and right sides.
Usage example:
https://stat.ethz.ch/pipermail/r-sig-geo/2005-October/000616.html

> p.s. exist any possibilities to select geometries with other topological
> criteria, for example dangle lines. i know that is possible to delete
> them with clean but i am looking for a possibility only to select them

v.edit can select:
http://grass.osgeo.org/grass64/manuals/html64_user/v.edit.html

In the new digitizer in wxpython there should be such functionality
to catch dangles.

Hope this helps a bit
Markus

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