title: GeoDjango: Determine the area of a polygon
body: <p>In my model I have a polygon field defined via</p>
  
  <pre><code>polygon = models.PolygonField(srid=4326, geography=True, null=True, blank=True)
  </code></pre>
  
  <p>When I want to determine the area of the polygon, I call</p>
  
  <pre><code>area_square_degrees = object.polygon.area
  </code></pre>
  
  <p>But how can I convert the result in <a href="http://en.wikipedia.org/wiki/Square_degree" rel="noreferrer">square degrees</a> into m2 with GeoDjango?
  <a href="https://gis.stackexchange.com/questions/9673/area-units-for-geos-area-property">This answer</a> does not work, since <code>area</code> does not have a method <code>sq_m</code>. Is there any built-in conversion?</p>