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

[David J. Bakeman]

Markus Neteler wrote:
> 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.
>    
Correct that was actually what I was using:  v.clean tool=break,rmdupl

Looking closer I see that when I run v.clean it doesn't even report the 
duplicates that v.in.ogr did but they are still there.  The only thing 
that differs in coordinates or attributes is the cat attribute that 
grass added.
>    
>> 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
>    
Thanks I'll see if I can upgrade.
> Markus
>
>