Bruce, You're absolutely right ;-)
Regards -- Pedro Doria Meunier <[EMAIL PROTECTED]> On Fri, 2008-10-24 at 12:25 -0600, Bruce Rindahl wrote: > After a quick look at the links, couldn't a stored procedure > (function) be used here? I envision the input is a polygon, grab the > outside ring, explode the vertices's to get a set of points(all > existing functions). Then the collection of points could be looped > through with the algorithm described to return a center and radius > which could then give a circle (buffer). > Or am I on drugs here.. > Bruce > > > Lee Meilleur wrote: > > Yes and yes to both questions, but the Roeck test is required by some > > states. And some states don't allow their politicians to draw their > > political boundaries. > > > > Thanks Martin, I'll test the convex hull and compare with the Roeck from > > our commercial software. > > > > Brent, thanks for the link, not sure if Paul will get the algorithm into > > the final release of PostGIS 1.3.4. I have two years to figure this out. > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Martin Davis > > Sent: Friday, October 24, 2008 11:40 AM > > To: PostGIS Users Discussion > > Subject: Re: [postgis-users] Roeck test > > > > > > Wouldn't it be easier and more accurate to use the convex hull of the > > polygon instead of the minimum enclosing ball? The CH will have smaller > > area (i.e. be a tighter bound on the area covered by the polygon), so it > > seems like it would give a more accurate basis for comparison. > > > > Lee Meilleur wrote: > > > > > Has anyone calculated the Roeck test using PostGIS? This is an area > > > based measure that computes the ratio of the area of a polygon to the > > > area of the minimum enclosing circle for the polygon. It's used to > > > measure compactness of districts for redistricting applications, > > > basically a way to test for gerrymandering. Thanks. > > > > > > Lee Meilleur > > > LCC-GIS Office > > > Minnesota Legislature > > > 100 Rev. Dr. MLK Jr Blvd. > > > 55 State Office Building > > > St. Paul, MN 55155 > > > 651.296.0098 Fax: 651.297.3697 > > > [EMAIL PROTECTED] > > > http://www.gis.leg.mn > > > > > > > > > _______________________________________________ > > > postgis-users mailing list [email protected] > > > http://postgis.refractions.net/mailman/listinfo/postgis-users > > > > > > > > > > > > > -- > > Martin Davis > > Senior Technical Architect > > Refractions Research, Inc. > > (250) 383-3022 > > > > _______________________________________________ > > postgis-users mailing list > > [email protected] > > http://postgis.refractions.net/mailman/listinfo/postgis-users > > _______________________________________________ > > postgis-users mailing list > > [email protected] > > http://postgis.refractions.net/mailman/listinfo/postgis-users > > > > > > > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users
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