[GRASS-user] v.generalize issues

[Christian Guirreri]

Success! Thanks for making this easy for the total noob that I am.

On Thu, Jun 30, 2011 at 11:04 AM, Markus Metz <
markus.metz.giswork at googlemail.com> wrote:

> On Thu, Jun 30, 2011 at 4:47 PM, Christian Guirreri
> <christian at guirreri.com> wrote:
> > I'm on GRASS 6.4.1. QGIS 1.7.0
> >
> In this version, v.generalize is still broken. You would need a recent
> version of GRASS 6.4.2. For Windows, you can get a recent version
> here:
>
> http://wingrass.fsv.cvut.cz/grass64/
>
> Markus M
>
>
> > On Thu, Jun 30, 2011 at 10:18 AM, Markus Metz
> > <markus.metz.giswork at googlemail.com> wrote:
> >>
> >> On Thu, Jun 30, 2011 at 4:01 PM, Christian Guirreri
> >> <christian at guirreri.com> wrote:
> >> > I'm a brand new user to GIS - my goal right now is to heavily simplify
> >> > Tiger
> >> > 2010 county and distrct data, without producing gaps between
> boundaries.
> >> > I've been testing this with v.generalize in grass via QuantumGIS -
> I've
> >> > had
> >> > tons of issues with the Grass toolbox crashing, but have narrowed down
> >> > to
> >> > using the Hermite algorithm. While it works, I'm having some bizarre
> >> > issues
> >> > with it. Apologies for the cross-post with the PostGIS mailing list.
> >> >
> >> > In the attached gif of California counties, from left to right, I have
> >> > used
> >> > the following tolerance values with the Hermite algorithm:
> >> >  - original
> >> >  - 1.0
> >> >  - 0.08
> >> >  - 0.01
> >> >  - 0.00001
> >> >
> >> > Why do counties disappear entirely as I decrease the tolerance?
> >> >
> >> This problem has been fixed in GRASS 6.4 only 2 weeks ago (June 13).
> >> Please update your GRASS version if possible.
> >>
> >> Markus M
> >>
> >>
> >> > In the Grass Tools I choose the v.generalize function. I choose
> Boundary
> >> > as
> >> > the feature type (though I've tried checking others, as well as all of
> >> > them
> >> > and it doesn't seem to change anything). Everything else is default,
> >> > except
> >> > for tolerance as notated above.
> >> >
> >> > When I tested this originally on only Arkansas and Mississippi, I got
> >> > really
> >> > nice results. I then tried it on the entire US and had the missing
> >> > counties
> >> > problem. So I tried only California, and still have the same issue.
> >> >
> >> > I've tried other algorithms, but this has so far given me the detail I
> >> > want
> >> > - of course sans counties! Any thoughts?
> >> >
> >> > Thanks,
> >> >  - Chris
> >> > _______________________________________________
> >> > grass-user mailing list
> >> > grass-user at lists.osgeo.org
> >> > http://lists.osgeo.org/mailman/listinfo/grass-user
> >> >
> >> >
> >
> >
>
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