function initialize(eventCenter, overlay, requestId) {
	  if (GBrowserIsCompatible()) {
		var map = new GMap2(document.getElementById("map_canvas"));
		map.setCenter(new GLatLng(52.0912623, 5.1227478), 12);
		map.addControl(new GSmallMapControl());
		//map.addControl(new GMapTypeControl());       
	
		// Add markers to the map at event locations if checked in ui
		var f = document.forms["cat_control"];
		var f2 = document.forms["cat_control_people"];
		
		//crew - shop
		if(overlay == 1) {
			for (id in vipbusPeople) {
			  var point = new GLatLng(vipbusPeople[id].lat, vipbusPeople[id].lng);				    
			  if(f2.elements["passie"].checked && vipbusPeople[id].cat == 6) {
				  map.addOverlay(createMarkerPeople(point, 6, vipbusPeople[id].name, vipbusPeople[id].descr, vipbusPeople[id].int_url, vipbusPeople[id].url));
			  }		  
			  if(f2.elements["gastro"].checked && vipbusPeople[id].cat == 7) {
				  map.addOverlay(createMarkerPeople(point, 7, vipbusPeople[id].name, vipbusPeople[id].descr, vipbusPeople[id].int_url, vipbusPeople[id].url));
			  }
			}
		}
		//kaart voor single evenement
		else if(overlay == 2) {
			for (id in vipbusEvents) {
				if (vipbusEvents[id].id == requestId) {
					if(vipbusEvents[id].cal == "true") map.setCenter(new GLatLng(vipbusEvents[id].lat, vipbusEvents[id].lng), 15);
					var point = new GLatLng(vipbusEvents[id].lat, vipbusEvents[id].lng);
					if(vipbusEvents[id].cal != "true") map.addOverlay(createMarker(point, vipbusEvents[id].cat, vipbusEvents[id].name, vipbusEvents[id].date, vipbusEvents[id].time, vipbusEvents[id].descr, vipbusEvents[id].location, vipbusEvents[id].id));
				}
			}
		}
		else  {	
			//hoofdkaart op homepage
			for (id in vipbusEvents) {
			  var point = new GLatLng(vipbusEvents[id].lat, vipbusEvents[id].lng);				    
			  if(f.elements["people"].checked && vipbusEvents[id].cat == 1 && vipbusEvents[id].cal != "true" && vipbusEvents[id].history != "true") {
				  map.addOverlay(createMarker(point, 1, vipbusEvents[id].name, vipbusEvents[id].date, vipbusEvents[id].time, vipbusEvents[id].descr, vipbusEvents[id].location, vipbusEvents[id].id));
			  }		  
			  if(f.elements["philo"].checked && vipbusEvents[id].cat == 3 && vipbusEvents[id].cal != "true" && vipbusEvents[id].history != "true") {
				  map.addOverlay(createMarker(point, 3, vipbusEvents[id].name, vipbusEvents[id].date, vipbusEvents[id].time, vipbusEvents[id].descr, vipbusEvents[id].location, vipbusEvents[id].id));
			  }
			  if(f.elements["products"].checked && vipbusEvents[id].cat == 2 && vipbusEvents[id].cal != "true" && vipbusEvents[id].history != "true") {
				  map.addOverlay(createMarker(point, 2, vipbusEvents[id].name, vipbusEvents[id].date, vipbusEvents[id].time, vipbusEvents[id].descr, vipbusEvents[id].location, vipbusEvents[id].id));
			  }
			  if(f.elements["places"].checked && vipbusEvents[id].cat == 5 && vipbusEvents[id].cal != "true" && vipbusEvents[id].history != "true") {
				  map.addOverlay(createMarker(point, 5, vipbusEvents[id].name, vipbusEvents[id].date, vipbusEvents[id].time, vipbusEvents[id].descr, vipbusEvents[id].location, vipbusEvents[id].id));
			  }
			  if(f.elements["projects"].checked && vipbusEvents[id].cat == 4 && vipbusEvents[id].cal != "true" && vipbusEvents[id].history != "true") {
				  map.addOverlay(createMarker(point, 4, vipbusEvents[id].name, vipbusEvents[id].date, vipbusEvents[id].time, vipbusEvents[id].descr, vipbusEvents[id].location, vipbusEvents[id].id));
			  }
			}
			if (eventCenter > 0) {
				for (id in vipbusEvents) {
					if (vipbusEvents[id].id == requestId && vipbusEvents[id].cal != "true") map.setCenter(new GLatLng(vipbusEvents[id].lat, vipbusEvents[id].lng), 14);
				}
			}
		}
	  }
	}