function initialize() {
if (GBrowserIsCompatible()) {
var map = new GMap2(document.getElementById("map_canvas")); var center = new GLatLng(13.42456,99.95671);
map.setCenter(center, 17);
map.addMapType(G_PHYSICAL_MAP);
map.removeMapType(G_NORMAL_MAP);
map.setUIToDefault();
var marker = new GMarker(center, {draggable: true});
map.addOverlay(marker);
GEvent.addListener(marker, "dragend", function() {
var point = marker.getPoint();
map.panTo(point);