[postgis-users] Roeck test

Brent Fraser bfraser at geoanalytic.com
Fri Oct 24 09:26:30 PDT 2008


Funny,  I was just doing some web surfing to find the algorithm for a Minimum Bounding Rotated Rectangle and came across this:

http://geometryalgorithms.com/Archive/algorithm_0107/algorithm_0107.htm

Brent

Paul Ramsey wrote:
> Wouldn't the ratio of area to perimeter be a similar metric? Also,
> wouldn't it be easier to just stop letting politicians draw their own
> boundaries? :)
> 
> I wonder what the algorithm for minimum enclosing circle is...
> 
> (Short answer, no, because we don't have a min-circle routine.)
> 
> P.
> 
> On Fri, Oct 24, 2008 at 8:59 AM, Lee Meilleur <lee.meilleur at gis.leg.mn> 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 redistr
> icting 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
>> lee.meilleur at gis.leg.mn
>> http://www.gis.leg.mn
>>
>>
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