Question

I want to integrate MarkerCluster with my database driven Google map and have been struggling to get it to work.

The first code example generates a map from a database that already has the multiple markers lat/long.

The second bit of code is a simple version of Marker Cluster.

How can I combine the two? Both are setup for V3 of the api.

    <script type="text/javascript">
    //<![CDATA[

    var customIcons = {
      restaurant: {
        icon: 'http://labs.google.com/ridefinder/images/mm_20_blue.png',
        shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
      },
      bar: {
        icon: 'http://labs.google.com/ridefinder/images/mm_20_red.png',
        shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
      }
    };

    function load() {
      var map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(47.6145, -122.3418),
        zoom: 13,
        mapTypeId: 'roadmap'
      });
      var infoWindow = new google.maps.InfoWindow;

      // Change this depending on the name of your PHP file
      downloadUrl("<?php bloginfo('stylesheet_directory'); ?>/phpsqlajax_genxml.php ", function(data) {
        var xml = data.responseXML;
        var markers = xml.documentElement.getElementsByTagName("marker");
        for (var i = 0; i < markers.length; i++) {
          var name = markers[i].getAttribute("name");
          var address = markers[i].getAttribute("address");
          var type = markers[i].getAttribute("type");
          var point = new google.maps.LatLng(
              parseFloat(markers[i].getAttribute("lat")),
              parseFloat(markers[i].getAttribute("lng")));
          var html = "<b>" + name + "</b> <br/>" + address;
          var icon = customIcons[type] || {};
          var marker = new google.maps.Marker({
            map: map,
            position: point,
            icon: icon.icon,
            shadow: icon.shadow
          });
          bindInfoWindow(marker, map, infoWindow, html);
        }
      });
    }

    function bindInfoWindow(marker, map, infoWindow, html) {
      google.maps.event.addListener(marker, 'click', function() {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
      });
    }

    function downloadUrl(url, callback) {
      var request = window.ActiveXObject ?
          new ActiveXObject('Microsoft.XMLHTTP') :
          new XMLHttpRequest;

      request.onreadystatechange = function() {
        if (request.readyState == 4) {
          request.onreadystatechange = doNothing;
          callback(request, request.status);
        }
      };

      request.open('GET', url, true);
      request.send(null);
    }

    function doNothing() {}

    //]]>
  </script>

The example below is Marker Cluster:

var center = new google.maps.LatLng(37.4419, -122.1419);
var options = {
  'zoom': 13,
  'center': center,
  'mapTypeId': google.maps.MapTypeId.ROADMAP
};

var map = new google.maps.Map(document.getElementById("map"), options);

var markers = [];
for (var i = 0; i < 100; i++) {
  var latLng = new google.maps.LatLng(data.photos[i].latitude,
      data.photos[i].longitude);
  var marker = new google.maps.Marker({'position': latLng});
  markers.push(marker);
}
var markerCluster = new MarkerClusterer(map, markers);

Answer 1

With a lot of trial and error and some help from @geocodezip:

   <script type="text/javascript">
    //<![CDATA[

    var customIcons = {
      restaurant: {
        icon: 'http://labs.google.com/ridefinder/images/mm_20_blue.png',
        shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
      },
      bar: {
        icon: 'http://labs.google.com/ridefinder/images/mm_20_red.png',
        shadow: 'http://labs.google.com/ridefinder/images/mm_20_shadow.png'
      }
    };

    function load() {
      var cluster = [];
      var map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(47.6145, -122.3418),
        zoom: 13,
        mapTypeId: 'roadmap'
      });
var infowindow = new google.maps.InfoWindow();

      // Change this depending on the name of your PHP file
      downloadUrl("<?php bloginfo('stylesheet_directory'); ?>/phpsqlajax_genxml.php ", function(data) {
        var xml = data.responseXML;
        var markers = xml.documentElement.getElementsByTagName("marker");
        for (var i = 0; i < markers.length; i++) {
          var name = markers[i].getAttribute("name");
          var address = markers[i].getAttribute("address");
          var type = markers[i].getAttribute("type");
          var point = new google.maps.LatLng(
              parseFloat(markers[i].getAttribute("lat")),
              parseFloat(markers[i].getAttribute("lng")));
          var html = "<b>" + name + "</b> <br/>" + address;
          var icon = customIcons[type] || {};
          var marker = new google.maps.Marker({
            map: map,
            position: point,
            icon: icon.icon,
            shadow: icon.shadow
          });
          google.maps.event.addListener(marker, 'click', (function(marker, i) {
                        return function() {
                            infowindow.setContent("Info on member here");
                            infowindow.open(map, marker);
                        }
                    })(marker, i));
          cluster.push(marker);
        }
        var mc = new MarkerClusterer(map,cluster);
      });
    }

    function bindInfoWindow(marker, map, infoWindow, html) {
      google.maps.event.addListener(marker, 'click', function() {
        infoWindow.setContent(html);
        infoWindow.open(map, marker);
      });
    }

    function downloadUrl(url, callback) {
      var request = window.ActiveXObject ?
          new ActiveXObject('Microsoft.XMLHTTP') :
          new XMLHttpRequest;

      request.onreadystatechange = function() {
        if (request.readyState == 4) {
          request.onreadystatechange = doNothing;
          callback(request, request.status);
        }
      };

      request.open('GET', url, true);
      request.send(null);
    }

    function doNothing() {}

    //]]>
  </script>