title: How to calculate the area of a polygon on the earth's surface using python?
body: <p>The title basically says it all. I need to calculate the area inside a polygon on the Earth's surface using Python. <a href="https://stackoverflow.com/questions/1340223/calculating-area-enclosed-by-arbitrary-polygon-on-earths-surface">Calculating area enclosed by arbitrary polygon on Earth&#39;s surface</a> says something about it, but remains vague on the technical details:</p>
  
  <blockquote>
    <p>If you want to do this with a more
    "GIS" flavor, then you need to select
    an unit-of-measure for your area and
    find an appropriate projection that
    preserves area (not all do). Since you
    are talking about calculating an
    arbitrary polygon, I would use
    something like a Lambert Azimuthal
    Equal Area projection. Set the
    origin/center of the projection to be
    the center of your polygon, project
    the polygon to the new coordinate
    system, then calculate the area using
    standard planar techniques.</p>
  </blockquote>
  
  <p>So, how do I do this in Python?</p>