[GRASS-user] r.to.vect and then v.clean using tool=rmarea createspolygons instead of holes.

[Moskovitz, Bob]

I followed your suggestion, but I'm still getting the same problem.  It seems strange that v.to.rast would create a vector file that has flawed topology.  Do you know of any alternative to v.clean with rmarea?

Btw, I also tried to use v.generalize with a very small threshold and then v.clean.  This method works for me.

> -----Original Message-----
> From: Alex Mandel [mailto:tech_dev at wildintellect.com]
> Sent: Thursday, December 11, 2008 3:14 PM
> To: Moskovitz, Bob
> Cc: Grass-User (E-mail)
> Subject: Re: [GRASS-user] r.to.vect and then v.clean using tool=rmarea
> createspolygons instead of holes.
> 
> 
> Moskovitz, Bob wrote:
> > Hello Grass-Users,
> >  
> > I'm having problems with this sequence of commands:
> >     r.to.vect -s input=lszone output=lszone10 feature=area
> >     v.clean input=lszone10 output=lszone10_clean 
> tool=rmarea thresh=2800
> >  
> > Below is the output.
> >  
> > Overlaying lszone and lszone10_clean, I see that there are 
> large holes
> > that have been replaced with polygons.  Is this a bug?
> >  
> > Btw, I've tried this with QGIS on Windows XP as well as 
> GRASS 6.4.svn
> > with the same results.
> >  
> > Bob
> >  
> 
> Hmm, I'm wondering if there's a flaw in the topology built by 
> r.to.vect
> 
> What happens if you run v.build before v.clean?
> 
> At second glance I see how if a small polygon gets removed 
> and it shared
> a border with the big polygon, that that border might not exist now.
> maybe add the bpol to tool=rmarea,bpol
> 
> Alex
> 
> 
>