[GRASS-user] generalize polygons including holes

Robert Nuske rnuske at gwdg.de
Tue Feb 10 00:08:44 PST 2015


Hi Markus,

> >> >>>> v.generalize does not distinguish between outer and inner rings, it
> >> >>>> simply goes through all boundaries and generalizes each one.
> >> >>> 
> >> >>> And this has always been the case or this is specific to GRASS7 ?
> >> >> 
> >> >> This has always been the case.
> >> > 
> >> > Then why doesn't there seem to be any generalization happening for the
> >> > hole
> >> > boundaries of the test dataset with grass64release ?
> >> 
> >> With the test dataset you provided, GRASS 6.4 does generalize the hole
> >> boundaries. I do not have the problem vector of Robert, so I can not
> >> say if the hole boundaries in that vector are generalized or not.
> > 
> > Please find attached a location with a test dataset (snipped of larger
> > vector map) and two images from generalizations carried out in GRASS
> > 6.4.4 (6.4.4-1~trusty5 from ppa:ubuntugis-unstable) and GRASS 7.0
> > (7.0.0+1svn64474~ubuntu14.04.1 from ppa:grass-devel).
> > Blue layer is generalized and red one is the original both at 50%
> > transparency.
> > 
> > 
> > For me, the results from GRASS 7.0 look as expected (inner rings
> > generalized) but v.generalize in GRASS 6.4 seems not to treat inner
> > rings.
> 
> Thanks for the test location, I could reproduce it, fixed in relbr64 r64478.

Thanks for fixing it!


cheers,
  robert



More information about the grass-user mailing list