L'ho usato insieme a jQuery e fa il lavoro:
var map;
var markers = [];
var infoWindow;
function initialize() {
var center = new google.maps.LatLng(-29.6833300, 152.9333300);
var mapOptions = {
zoom: 5,
center: center,
panControl: false,
zoomControl: false,
mapTypeControl: false,
scaleControl: false,
streetViewControl: false,
overviewMapControl: false,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
$.getJSON('jsonbackend.php', function(data) {
infoWindow = new google.maps.InfoWindow();
$.each(data, function(key, val) {
if(val['LATITUDE']!='' && val['LONGITUDE']!='')
{
// Set the coordonates of the new point
var latLng = new google.maps.LatLng(val['LATITUDE'],val['LONGITUDE']);
//Check Markers array for duplicate position and offset a little
if(markers.length != 0) {
for (i=0; i < markers.length; i++) {
var existingMarker = markers[i];
var pos = existingMarker.getPosition();
if (latLng.equals(pos)) {
var a = 360.0 / markers.length;
var newLat = pos.lat() + -.00004 * Math.cos((+a*i) / 180 * Math.PI); //x
var newLng = pos.lng() + -.00004 * Math.sin((+a*i) / 180 * Math.PI); //Y
var latLng = new google.maps.LatLng(newLat,newLng);
}
}
}
// Initialize the new marker
var marker = new google.maps.Marker({map: map, position: latLng, title: val['TITLE']});
// The HTML that is shown in the window of each item (when the icon it's clicked)
var html = "<div id='iwcontent'><h3>"+val['TITLE']+"</h3>"+
"<strong>Address: </strong>"+val['ADDRESS']+", "+val['SUBURB']+", "+val['STATE']+", "+val['POSTCODE']+"<br>"+
"</div>";
// Binds the infoWindow to the point
bindInfoWindow(marker, map, infoWindow, html);
// Add the marker to the array
markers.push(marker);
}
});
// Make a cluster with the markers from the array
var markerCluster = new MarkerClusterer(map, markers, { zoomOnClick: true, maxZoom: 15, gridSize: 20 });
});
}
function markerOpen(markerid) {
map.setZoom(22);
map.panTo(markers[markerid].getPosition());
google.maps.event.trigger(markers[markerid],'click');
switchView('map');
}
google.maps.event.addDomListener(window, 'load', initialize);