I wonder about the PostGIS value, too. JTS gives 9.336164500133789.
On 2/23/2012 6:58 AM, 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? Best regards Astrid [1] http://tandler.com/communal_gis/watermanagment/wastewater/sewer-gis-kanalplusplus.htm
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