google.load('maps', '3', {
	other_params : 'sensor=false'
});

google.setOnLoadCallback(initialize);

var markerClusterer = null;
var map = null;
var imageUrl = 'http://chart.apis.google.com/chart?cht=mm&chs=24x32&'
		+ 'chco=FFFFFF,008CFF,000000&ext=.png';

function refreshMap() {
	if (markerClusterer) {
		markerClusterer.clearMarkers();
	}

	var markers = [];

	var markerImage = new google.maps.MarkerImage(imageUrl,
			new google.maps.Size(24, 32));

	for ( var i = 0; i < data.count; ++i) {
		var latLng = new google.maps.LatLng(data.item[i].lat, data.item[i].lng);
		var marker = new google.maps.Marker({
			position : latLng,
			draggable : true,
			icon : markerImage
		});
		markers.push(marker);
	}

	markerClusterer = new MarkerClusterer(map, markers, {
		gridSize : 20,
	});
}

function initialize() {
	map = new google.maps.Map(document.getElementById('map'), {
		zoom : 7,
		center : new google.maps.LatLng(49.827778, 15.375833),
		mapTypeId : google.maps.MapTypeId.ROADMAP,
		panControl : false,
		zoomControl : true,
		mapTypeControl : false,
		scaleControl : false,
		streetViewControl : false,
		overviewMapControl : false
	});

	refreshMap();
}