function initialize() {
      if (GBrowserIsCompatible()) {
        var map = new GMap2(document.getElementById("map_canvas"));
        map.setCenter(new GLatLng(51.524911,-0.140175), 15);
 
	var bounds = map.getBounds();
	var southWest = bounds.getSouthWest();
	var northEast = bounds.getNorthEast();
	var lngSpan = northEast.lng() - southWest.lng();
	var latSpan = northEast.lat() - southWest.lat();


		var point = new GLatLng(51.523511,-0.139475);
		map.addOverlay(new GMarker(point));

	}
    }