title: OpenLayer Coordinate System
body: <p>I'm struggling to understand the coordinate system used by OpenLayers.</p>
  
  <p>Leicester, UK is at approx. </p>
  
  <pre><code>Latitude:  52.63973017532399
  Longitude: -1.142578125
  </code></pre>
  
  <p>But to display the same location using OpenLayers I have to use:</p>
  
  <pre><code>Latitude:  6915601.9146245
  Longitude: -125089.1967713
  </code></pre>
  
  <p>e.g:</p>
  
  <pre><code>var center  = new OpenLayers.LonLat(-125089.1967713, 6915601.9146245);
  var map     = new OpenLayers.Map("demoMap");
  map.addLayer(new OpenLayers.Layer.OSM());
  map.setCenter(center, 12);
  </code></pre>
  
  <p>These are clearly not Latitude-Longitude coordinates, is there some conversion I need to take account of?</p>
  
  <p>A working example is <a href="http://craig-russell.co.uk/demos/openlayers/so_map.html" rel="noreferrer">http://craig-russell.co.uk/demos/openlayers/so_map.html</a></p>