Google MarkerClusterer: decluster markers below a certain zoom level?

Question

I\'m using Google MarkerClusterer. I\'d like to decluster all the markers whenever the map goes above zoom level 15.

There is a maxZoom setting in the

Answer 1

 var markerClusterer = new MarkerClusterer(map, myMarkers, {
     maxZoom: 15,
     zoomOnClick: false
   });
//zoom 0 corresponds to a map of the Earth fully zoomed out, 20 is closeup
//markerCluster goes away after zoom 
//turn off zoom on click or spiderfy won't work 

Answer 2

Setting the maxZoom level on this example, declusters all the markers for zoom level 8 and above.

To reproduce:

1. set Max zoom level to 7
2. click refresh map
3. change the zoom level to 0 (the furthest out)
4. click the "+" on the zoom slider 8 times.

The documentation for MarkerClustererPlus is a little clearer:

maxZoom | number | The maximum zoom level at which clustering is enabled or null if clustering is to be enabled at all zoom levels. The default value is null.

code snippet:

var styles = [
  [{
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/people35.png',
    height: 35,
    width: 35,
    anchor: [16, 0],
    textColor: '#ff00ff',
    textSize: 10
  }, {
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/people45.png',
    height: 45,
    width: 45,
    anchor: [24, 0],
    textColor: '#ff0000',
    textSize: 11
  }, {
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/people55.png',
    height: 55,
    width: 55,
    anchor: [32, 0],
    textColor: '#ffffff',
    textSize: 12
  }],
  [{
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/conv30.png',
    height: 27,
    width: 30,
    anchor: [3, 0],
    textColor: '#ff00ff',
    textSize: 10
  }, {
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/conv40.png',
    height: 36,
    width: 40,
    anchor: [6, 0],
    textColor: '#ff0000',
    textSize: 11
  }, {
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/conv50.png',
    width: 50,
    height: 45,
    anchor: [8, 0],
    textSize: 12
  }],
  [{
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/heart30.png',
    height: 26,
    width: 30,
    anchor: [4, 0],
    textColor: '#ff00ff',
    textSize: 10
  }, {
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/heart40.png',
    height: 35,
    width: 40,
    anchor: [8, 0],
    textColor: '#ff0000',
    textSize: 11
  }, {
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/heart50.png',
    width: 50,
    height: 44,
    anchor: [12, 0],
    textSize: 12
  }],
  [{
    url: 'https://cdn.jsdelivr.net/npm/marker-clusterer-plus@2.1.4/images/pin.png',
    height: 48,
    width: 30,
    anchor: [-18, 0],
    textColor: '#ffffff',
    textSize: 10,
    iconAnchor: [15, 48]
  }]
];

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(data) {
  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.photos.length; ++i) {
    var latLng = new google.maps.LatLng(data.photos[i].latitude,
      data.photos[i].longitude)
    var marker = new google.maps.Marker({
      position: latLng,
      draggable: true,
      icon: markerImage
    });
    markers.push(marker);
  }

  var zoom = parseInt(document.getElementById('zoom').value, 10);
  var size = parseInt(document.getElementById('size').value, 10);
  var style = parseInt(document.getElementById('style').value, 10);
  zoom = zoom === -1 ? null : zoom;
  size = size === -1 ? null : size;
  style = style === -1 ? null : style;

  markerClusterer = new MarkerClusterer(map, markers, {
    maxZoom: zoom,
    gridSize: size,
    styles: styles[style],
    imagePath: 'https://developers.google.com/maps/documentation/javascript/examples/markerclusterer/m'
  });
}

function initialize() {
  map = new google.maps.Map(document.getElementById('map'), {
    zoom: 2,
    center: new google.maps.LatLng(39.91, 116.38),
    mapTypeId: google.maps.MapTypeId.ROADMAP
  });

  var refresh = document.getElementById('refresh');
  google.maps.event.addDomListener(refresh, 'click', refreshMap);

  var clear = document.getElementById('clear');
  google.maps.event.addDomListener(clear, 'click', clearClusters);

  $.getJSON("https://api.myjson.com/bins/6ad78", function(data, textStatus, jqXHR) {
    console.log(textStatus);
    refreshMap(data);
  });
}

function clearClusters(e) {
  e.preventDefault();
  e.stopPropagation();
  markerClusterer.clearMarkers();
}

google.maps.event.addDomListener(window, 'load', initialize);

body {
  margin: 0;
  padding: 10px 20px 20px;
  font-family: Arial;
  font-size: 16px;
}

#map-container {
  padding: 6px;
  border-width: 1px;
  border-style: solid;
  border-color: #ccc #ccc #999 #ccc;
  -webkit-box-shadow: rgba(64, 64, 64, 0.5) 0 2px 5px;
  -moz-box-shadow: rgba(64, 64, 64, 0.5) 0 2px 5px;
  box-shadow: rgba(64, 64, 64, 0.1) 0 2px 5px;
  width: 800px;
}

#map {
  width: 800px;
  height: 400px;
}

#actions {
  list-style: none;
  padding: 0;
}

#inline-actions {
  padding-top: 10px;
}

.item {
  margin-left: 20px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk"></script>
<!-- scr -- ipt src="https://googlemaps.github.io/js-marker-clusterer/examples/data.json"></scr -- ipt -->
<script src="https://unpkg.com/@google/markerclustererplus@4.0.1/dist/markerclustererplus.min.js"></script>
<h3>An example of MarkerClusterer v3</h3>
<div id="map-container">
  <div id="map"></div>
</div>
<div id="inline-actions">
  <span>Max zoom level:
        <select id="zoom">
          <option value="-1">Default</option>
          <option value="7">7</option>
          <option value="8">8</option>
          <option value="9">9</option>
          <option value="10">10</option>
          <option value="11">11</option>
          <option value="12">12</option>
          <option value="13">13</option>
          <option value="14">14</option>
        </select>

      </span>
  <span class="item">Cluster size:
        <select id="size">
          <option value="-1">Default</option>
          <option value="40">40</option>
          <option value="50">50</option>
          <option value="70">70</option>
          <option value="80">80</option>
        </select>
      </span>
  <span class="item">Cluster style:
        <select id="style">
          <option value="-1">Default</option>
          <option value="0">People</option>
          <option value="1">Conversation</option>
          <option value="2">Heart</option>
          <option value="3">Pin</option>
       </select>
       <input id="refresh" type="button" value="Refresh Map" class="item"/>
       <a href="#" id="clear">Clear</a>
    </div>

Answer 3

You can always wrire different code, for example combine

• map.getZoom(),
• marker[i].setVisible(true) (or false) and
• google.maps.event.addListener(map, 'zoom_changed', ...

Something like this:

function show_hide_markers(zoom) {
    var markerVisible;
    for (var i = 0; i < markers.length; i++) {
        if (zoom <= zoomRanges[i][1] && zoom >= zoomRanges[i][0] ) { 
             markerVisible = true
        } else markerVisible = false;

        if (markers[i].getVisible() != markersVisible) {
        markers[i].setVisible(markersVisible);}
    }
}

// ...

google.maps.event.addListener(map, 'zoom_changed', function () {
    show_hide_markers(map.getZoom());
});

Create markers array first. Zoom level ranges can be kept in a separate array corresponding somehow to indexes in markers array (zoomRanges here). Zoom levels can be taken also from the original array (list) used to create the markers array.

In this example zoom range is assigned to each marker individually, but two dimensional arrays can be used and markerVisible obtained for entire clusters.

If markers number is not extremely high it should be sufficient. Probably adding / removing culd be applied instead of setting visibility.

Unlike marker manager (at least recently in some cases) this works even under API3 + API key applied. I was forced to do this yesterday / today.