var rotate = 'a';

function OSMGetTileUrl(a,b) {
	var rot = rotate;
	if (rot == 'a') {
		rotate = 'b';
	} else if (rot == 'b') {
		rotate = 'c';
	} else {
		rotate = 'a';
	}
	return 'http://'+rot+'.tile.openstreetmap.org/'+b+'/'+a.x+'/'+a.y+'.png';
}

var OSM_MAP;

function startOSM() {
	checkMap();
	var copyright = new GCopyright(
			1,	new GLatLngBounds(new GLatLng(53.8136257,-3.0981445),new GLatLng(53.8654855,-2.9663944) ),
			17, 'Open Street Map Community');

	var copyrightCollection = new GCopyrightCollection('');
	copyrightCollection.addCopyright(copyright);

	var tilelayers = [new GTileLayer(copyrightCollection,1,17)];
	tilelayers[0].getTileUrl = OSMGetTileUrl;

	OSM_MAP = new GMapType(tilelayers, G_SATELLITE_MAP.getProjection(), 'O.S.M.');
	map.addMapType(OSM_MAP);
	
	//map.addControl(new GMapTypeControl());
	Element.show('maptab4');
}