title: geoNear returns incorrect distance
body: <p>I'm playing with geo features of mongodb in Java and i'm facing to the following problem running command 'geoNear':</p>
  
  <p>Given:</p>
  
  <ul>
  <li>A collection named 'GEOENTITIES' with GeoJSON objects</li>
  <li><p>This collection is indexed with the Java code (using Jongo):</p>
  
  <pre><code>collection.ensureIndex("{ coordinates : '2dsphere' }");
  </code></pre></li>
  <li><p>A document (named 'A' for the example) exists with coordinates equals to [48.0, 9.0]</p></li>
  </ul>
  
  <p>When executing :</p>
  
  <pre><code>{geoNear: 'GEOENTITIES', near: [48.0,9.1], spherical: true, num: 5, distanceMultiplier: 6371}
  </code></pre>
  
  <p>Then:</p>
  
  <p>I have the command result:</p>
  
  <pre><code>{ "dis" : 11.11949328574724 , "obj" : { "coordinates" : [ 48.0 , 9.0] , "_id" : { "$oid" : "51a62a5485878b1ceca38ab3"} , "name" : "Toto"}}
  </code></pre>
  
  <p>Why the distance is 11.11 (kilometers) whereas the calculated one from <a href="http://williams.best.vwh.net/gccalc.htm" rel="nofollow">http://williams.best.vwh.net/gccalc.htm</a> - for example - is 7.46 ? 
  I think i did something wrong but don't see what, maybe someone more experimented can help?</p>