On Thu, Jun 30, 2011 at 4:47 PM, Christian Guirreri <christ...@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.gisw...@googlemail.com> wrote: >> >> On Thu, Jun 30, 2011 at 4:01 PM, Christian Guirreri >> <christ...@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@lists.osgeo.org >> > http://lists.osgeo.org/mailman/listinfo/grass-user >> > >> > > > _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user