title: Geo question: How to generate a .wld file given some ground control points?
body: <p>OK, so I have a jpeg and a bunch of ground control points (x/y pixels and corresponding lat/lon references).</p>
  
  <p>I'd like to generate a .wld world file to accompany the jpeg, from the command line. My coordinate system is Google Maps, i.e. EPSG:900913. </p>
  
  <p>I know that I can use gdal_transform to generate a .vrt given the gcps, but what I need is a .wld file. (Not really clear on the difference, but that's definitely what I need!)</p>
  
  <p>Anyone have any idea how to do this?</p>
  
  <p>Thanks
  Richard</p>