docs: function(lonlat) {
          var res = this.ovmap.getResolution();
          var extent = this.ovmap.getExtent();
          if (extent) {
              return {
                  x: Math.round(1/res * (lonlat.lon - extent.left)),
                  y: Math.round(1/res * (extent.top - lonlat.lat))
              };
          } 
      }