Success! Thanks for making this easy for the total noob that I am. On Thu, Jun 30, 2011 at 11:04 AM, Markus Metz < [email protected]> wrote:
> On Thu, Jun 30, 2011 at 4:47 PM, Christian Guirreri > <[email protected]> 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 > > <[email protected]> wrote: > >> > >> On Thu, Jun 30, 2011 at 4:01 PM, Christian Guirreri > >> <[email protected]> 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 > >> > [email protected] > >> > http://lists.osgeo.org/mailman/listinfo/grass-user > >> > > >> > > > > > >
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