title: Units to use for maxdistance and MongoDB?
body: <p>I am trying to get my head around MongoDB and geospatial searches.
  Basically what I want is for users to be able to query documents (images) that
  are shot within a set distance from the users current location. So I the user is searching for all images that are shot within 1 km from where he is standing I try to use 
  the below example but I have no idea what to set as the maxdistance value.</p>
  
  <pre><code>db.places.find({ loc : { $near : [50,50] , $maxDistance : 5 }})
  </code></pre>
  
  <p>So my question is what do I set as maxdistance if I am searching for documents
  within a 1 km radius?</p>
  
  <p>I am totally stuck here.</p>