[GRASS-user] Unable to get rid of duplicate polygons

[Markus Neteler]

On Sun, Apr 1, 2012 at 9:45 PM, David J. Bakeman <dbakeman at comcast.net> wrote:
> I didn't find an answer in the archives so.
>
> I have a shapefile of polygons and some of the polygons are duplicated.  I
> thought I could use v.clean tool=rmdupl to get rid of these polygons.  I use
> v.in.ogr to read it in and I get the following:
>
> WARNING: 8 areas represent more (overlapping) features, because polygons
>          overlap in input layer(s). Such areas are linked to more than 1
>          row in attribute table. The number of features for those areas is
>          stored as category in layer 2
>
> That is correct in that there are 8 duplicate polygons but the only
> different attribute is the cat which grass added?  What am I missing?  I
> then tried v.clean tool=bpol,rmdupl and nothing changes it still has the 8
> duplicates.  What am I doing wrong?

I think that you need to add the break tool for v.clean.

> I am using grass 6.3.0 on fedora core 14 linux.

Please note that you can upgrade to grass-6.4.0-4.fc14:
http://koji.fedoraproject.org/koji/buildinfo?buildID=263115

Markus