title: Convert between coordinate systems with GeoDjango
body: <p>I'm trying to add coordinate information to my database, adding <code>django.contrib.gis</code> support to my app. I'm writing a <code>south</code> data migration that takes the addresses from the database, and asks Google for the coordinates (so far I think my best bet is to use <code>geopy</code> for this).</p>
  
  <p>Next I need to convert the returned coordinates from <code>WGS84:4326</code>, Google's coordinate system, to <code>WGS84:22186</code>, my coordinate system.</p>
  
  <p>I'm lost among the GeoDjango docs trying to find a way to do this. This far, I gather I need to do this:</p>
  
  <pre><code>gcoord = SpatialReference("4326")
  mycoord = SpatialReference("22186")
  trans = CoordTransform(gcoord, mycoord)
  </code></pre>
  
  <p>but then, I don't know how to use that <code>CoordTransform</code> object.. seems to be used by GDAL's data objects, but that's overkill for what I want to do..</p>