Shouldn't the geodesic area always be greater than the planar area of a polygon?
Tested in ArcMap and ArcGIS Pro, but several my polygons in a shapefile are having projected areas that are greater than the geodesic area.
I've loaded in a shapefile that has a GCS of WGS1984; the dataframe is set to GCS: WGS1984. Once loaded I perform the following:
- Add Field to attribute table and set to double
- Right click field and selected Field Calculator
- Supply the following Python input:
- Select the Project tool in Data Management > Projections and Transformations
- Project the layer to PCS: World Sinusoidal
Then I use Python to check the 2 fields against one another. A quick check of:
# pseudocode for each polygon: diff = geodesic_value - projected_value
A negative value for
diff means that projected was larger; postive is the inverse. It was my understanding that geodesic would (and should) always be larger.