I'm working with GeoDjango and have a polygon in the WGS84 projection. I need to find its area in square meters. When I call polygon.area, I get some float out and I have no idea what the units of it are.
For example, Central Park in New York (843 acres according to Wikipedia) has roughly these coordinates (WGS84):
MULTIPOLYGON (((-73.9582363278800017 40.8002491235089977, -73.9489666135250019 40.7967404799830007, -73.9729992062979989 40.7639841980140005, -73.9820972592760029 40.7681446212439980, -73.9582363278800017 40.8002491235089977)))
Accessing the "area" property by calling polygon.area yields 0.00038966160697
When I plug the polygon WKT into PostGIS directly and call ST_Area (as suggested here: How can I measure area from geographic coordinates?), I get 3650892.09953911 (which is in square meters), which comes out to about 920 acres, which is about right (I didn't digitize Central Park perfectly). I'd prefer not to have to do raw SQL calls in the code to avoid potential SQL injections. Is there a way to get to this number straight from GEOS?