Google maps - sloučení ikon (markers clustering)

  <div id="map" style="width: 100%; height: 800px;"></div>

  <script type="text/javascript">
     var map = new google.maps.Map(document.getElementById('map'), {
      zoom: 8,
      center: new google.maps.LatLng(49.664730, 15.795109),
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });

    var locations = [
      ['lokalita 1', 49.664948, 14.503054],
      ['lokalita 2', 49.792277, 15.580362]
    ];

    var infowindow = new google.maps.InfoWindow();

    var marker, i;

    for (i = 0; i < locations.length; i++) {  
      marker = new google.maps.Marker({
        position: new google.maps.LatLng(locations[i][1], locations[i][2]),
        map: map
      });

      google.maps.event.addListener(marker, 'click', (function(marker, i) {
        return function() {
          infowindow.setContent(locations[i][0]);
          infowindow.open(map, marker);
        }
      })(marker, i));
    }
  </script>