On Thu, Feb 23, 2012 at 02:58:49PM -0000, Astrid Emde wrote: > Hello, > > I calculate the area of polygons and get different results with diffrent > programms. > > Here is an example polygon: > > Select st_area(geometryfromtext( > 'POLYGON (( > 2569220.83 5630370.607, > 2569215.357 5630374.968, > 2569216.017 5630375.795, > 2569216.19 5630376.01, > 2569221.663 5630371.649, > 2569220.83 5630370.607 > ))',31466) ); > > These are the results that I get: > * PostGIS: 9.337890625 (with "POSTGIS="1.5.1" GEOS="3.2.0-CAPI-1.6.0") > * AutoCAD Map 2012: 9.3362 > * Kanal++ [1]: 9.3361645 > > PostGIS gives back a slightly bigger area than the other programms. Do you > know why and who is right?
PostGIS area calculator improved in 1.5.4 (yet to be released). BTW, are those meters ? You're worried of 0.001 square meters precision ? What's the precision of your coordinates ? Are your straight lines in your model really straight in the phisical world ? --strk; ,------o-. | __/ | Delivering high quality PostGIS 2.0 ! | / 2.0 | http://strk.keybit.net - http://vizzuality.com `-o------' _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
