I have a shapefile with 62.000 polygons.
I have created two fields (Double) AREA1 and AREA2 with identical properties.
On AREA1 I have calculated the area of polygons with Calculate Geometry > area process.
On AREA2 I have calculated the area of polygons with Field calculator and the command: !shape.area!
When I compare the difference between the two fields ([AREA1] - [AREA2]), I find 30 polygons with no zero difference less than 0,01 square meters.
Is there a different algorithm for these processes?
Does anyone know why is this happening?
does the file have a defined coordinate system? problems in calculating shape geometry arise when there is no know coordinate system. This is well documented on this site.
The shapefile has a coordinate system defined (Greek Grid).
I tried yesterday after publishing my question to calculate with and without defined Projection and the result was the same.