var centerLatitude = 51.63462075061097;
var centerLongitude = -0.4882049560546875;
var startZoom = 13;
var currZoom = startZoom;
var markersArray = new Array();
var map;
var description = '';

function addMarker(latitude, longitude, description)
{
    var marker = new GMarker(new GLatLng(latitude, longitude));
    GEvent.addListener(marker, 'click',

        function()
        {
            marker.openInfoWindowHtml(description);
        }
    );

map.addOverlay(marker);

}

function init()
{
   if (GBrowserIsCompatible()) 
   {
      map = new GMap2(document.getElementById("googlemap"));
      map.addControl(new GLargeMapControl());	  
	  map.addControl(new GMapTypeControl());
      map.setMapType(G_HYBRID_MAP);
      addMarker(centerLatitude, centerLongitude, description);	  
      var location = new GLatLng(centerLatitude, centerLongitude);
      map.setCenter(location, startZoom);      
      var marker = new GMarker(location);

    }
}

window.onload = init;
window.onunload = GUnload;