function initBiker() {
							var mgr = new MarkerManager(map306004);
					
							dojo.xhrGet({
							url: "/geo/ajax/layeritems/type/biker/title/Biker/lat/" + map306004.getCenter().lat() + "/lng/" + map306004.getCenter().lng() + "/zoom/" + map306004.getZoom() + "/pixel/" + map306004.getSize().width,
							handleAs: "json",
							load: function (data,ioArgs){
								var batch = [];
								for (var i in data["items"]){
									var point = new GPoint(data["items"][i]["lng"], data["items"][i]["lat"]);
									var marker = createMarker(point, data["items"][i]["url"], data["items"][i]["img"], data["items"][i]["login"],"large");
									batch.push(marker);
								}
								mgr.addMarkers(batch,0);
								mgr.refresh();
							}
							});
					
							return mgr;
						}var display_biker = false;
					  var mgr_biker = null;
						function switchBiker() {
							var icon = dojo.byId("bikerIcon");
							var tooltip = dojo.byId("bikerTooltip");
							if (!display_biker) {
								mgr_biker = initBiker();
								display_biker = true;
								dojo.attr(icon,"src","/app/i/layerbiker_on.gif");
								dojo.attr(tooltip,"innerHTML","Biker<br />- Aus -");
							} else {
								mgr_biker.clearMarkers();
								mgr_biker = null;
								display_biker = false;
								dojo.attr(icon,"src","/app/i/layerbiker.gif");
								dojo.attr(tooltip,"innerHTML","Biker<br />- An -");
							}
						}