code: function (viewPortPx) {
          var lonlat = null;
          if ( (this.mapObject != null) && 
               (this.getMapObjectCenter() != null) ) {
              var moPixel = this.getMapObjectPixelFromOLPixel(viewPortPx);
              var moLonLat = this.getMapObjectLonLatFromMapObjectPixel(moPixel);
              lonlat = this.getOLLonLatFromMapObjectLonLat(moLonLat);
          }
          return lonlat;
      }
docs: ***************************************************** /* /*                 Baselayer Functions /* ***************************************************** 
  Method: getLonLatFromViewPortPx
  Get a map location from a pixel location
  
  Parameters:
  viewPortPx - {<OpenLayers.Pixel>}
  
  Returns:
  {<OpenLayers.LonLat>} An OpenLayers.LonLat which is the passed-in view
  port OpenLayers.Pixel, translated into lon/lat by map lib
  If the map lib is not loaded or not centered, returns null