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<!DOCTYPE html>
<html lang="en">
<title>Display clusters with a Symbol Layer - Azure Maps Web SDK Samples</title>
<meta charset="utf-8" />
<link rel="shortcut icon" href="/favicon.ico"/>
<meta http-equiv="x-ua-compatible" content="IE=Edge" />
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no" />
<meta name="description" content="This sample shows how to enable point based clustering on a data source and render them with different symbols." />
<meta name="keywords" content="Microsoft maps, map, gis, API, SDK, markers, pins, pushpins, symbols, layer, clustering, superclusterer, earthquakes, USGS" />
<meta name="author" content="Microsoft Azure Maps" />
<!-- Add references to the Azure Maps Map control JavaScript and CSS files. -->
<link rel="stylesheet" href="" type="text/css" />
<script src=""></script>
<script type='text/javascript'>
var map, datasource;
//GeoJSON feed of all earthquakes from the past 30 days. Sourced from the USGS.
var earthquakeFeed = "";
//Find more earthquake data feeds here:
function GetMap() {
//Point the Azure Maps domain to the US Azure Gov Cloud domain.
//Initialize a map instance.
map = new atlas.Map('myMap', {
center: [-97, 39],
zoom: 3,
style: 'grayscale_dark',
view: 'Auto',
//Add authentication details for connecting to Azure Maps.
authOptions: {
//Use Azure Active Directory authentication.
authType: 'anonymous',
clientId: 'c9f2f391-13f1-407b-a4a5-f0a241bacfbf', //Your Azure Active Directory client id for accessing your Azure Maps account.
getToken: function (resolve, reject, map) {
//URL to your authentication service that retrieves an Azure Active Directory Token.
var tokenServiceUrl = '';
fetch(tokenServiceUrl).then(r => r.text()).then(token => resolve(token));
//Alternatively, use an Azure Maps key. Get an Azure Maps key at NOTE: The primary key should be used as the key.
//authType: 'subscriptionKey',
//subscriptionKey: '<Your Azure Maps Key>'
//Wait until the map resources are ready.'ready', function () {
//Create an array of custom icon promises to load into the map.
var iconPromises = [
map.imageSprite.add('earthquake_icon', '../Common/images/icons/earthquake_icon.png'),
map.imageSprite.add('warning_triangle_icon', '../Common/images/icons/warning_triangle_icon.png')
//Load all the custom image icons into the map resources.
Promise.all(iconPromises).then(function () {
//Create a data source and add it to the map.
datasource = new atlas.source.DataSource(null, {
//Tell the data source to cluster point data.
cluster: true
//Add two symbol layers to the map, one for clusters, one for individual points.
//Create a symbol layer to render the clusters.
new atlas.layer.SymbolLayer(datasource, null, {
iconOptions: {
image: 'warning_triangle_icon'
textOptions: {
textField: ['get', 'point_count_abbreviated'],
offset: [0, -0.4]
//Create a layer to render the individual locations.
new atlas.layer.SymbolLayer(datasource, null, {
iconOptions: {
image: 'earthquake_icon'
filter: ['!', ['has', 'point_count']] //Filter out clustered points from this layer.
//Retrieve a GeoJSON data set and add it to the data source.
<body onload="GetMap()">
<div id="myMap" style="position:relative;width:100%;min-width:290px;height:600px;"></div>
<fieldset style="width:calc(100% - 30px);min-width:290px;margin-top:10px;">
<legend><h1 style="font-size:16px">Display clusters with a Symbol Layer</h1></legend>
This sample shows how to enable point based clustering on a data source and render them with different symbols. Clustered points have four properties;
<li>cluster - A boolean value indicating that it is a cluster.</li>
<li>cluster_id - A unique id for the cluster which can be used with the DataSource getClusterExpansionZoom, getClusterChildren, and getClusterLeaves functions.</li>
<li>point_count - The number of points the cluster contains.</li>
<li>point_count_abbreviated - A string that abbreviates the point_count value if it is long. (i.e. 4,000 becomes 4K)</li>