title: how to make that "$nearSphere" return also the items without any coordinates?
body: <p>I try to do a <code>$nearSphere</code> query like below :</p>
  
  <pre><code>"coordinates":{
    "$nearSphere":{
      "$geometry":{
        "type":"Point",
        "coordinates":[7.16,47.13]}}},
  </code></pre>
  
  <p>The problem is that it doesn't return me the documents that doesn't have a node "<code>coordinates</code>" (even at the end of the list). Is their a way to force <code>$nearSphere</code> to return documents (at the end of the list) that don't have a node "<code>coordinates</code>" node ?</p>