I'm on GRASS 6.4.1. QGIS 1.7.0 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 > > > > >
_______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
