This example shows how to read data from a UTFGrid source.

Point to a country to see its name and flag.

Tiles made with [TileMill](http://tilemill.com). Hosting on MapBox.com or with open-source [TileServer](https://github.com/klokantech/tileserver-php/).
<!DOCTYPE html>
    <link rel="stylesheet" href="https://openlayers.org/en/v5.3.0/css/ol.css" type="text/css">
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>

      #country-name {
        color: black;
        font-size: 12pt;
        font-weight: bold;
        text-shadow: white 0.1em 0.1em 0.2em;
    <div id="map" class="map"></div>
    <div style="display: none;">
      <!-- Overlay with the country info -->
      <div id="country-info">
        <div id="country-name">&nbsp;</div>
        <img id="country-flag" src="" />
      import Map from 'ol/Map.js';
      import Overlay from 'ol/Overlay.js';
      import View from 'ol/View.js';
      import TileLayer from 'ol/layer/Tile.js';
      import TileJSON from 'ol/source/TileJSON.js';
      import UTFGrid from 'ol/source/UTFGrid.js';

      var key = 'Your Mapbox access token from http://mapbox.com/ here';

      var mapLayer = new TileLayer({
        source: new TileJSON({
          url: 'https://api.tiles.mapbox.com/v4/mapbox.geography-class.json?secure&access_token=' + key

      var gridSource = new UTFGrid({
        url: 'https://api.tiles.mapbox.com/v4/mapbox.geography-class.json?secure&access_token=' + key

      var gridLayer = new TileLayer({source: gridSource});

      var view = new View({
        center: [0, 0],
        zoom: 1

      var mapElement = document.getElementById('map');
      var map = new Map({
        layers: [mapLayer, gridLayer],
        target: mapElement,
        view: view

      var infoElement = document.getElementById('country-info');
      var flagElement = document.getElementById('country-flag');
      var nameElement = document.getElementById('country-name');

      var infoOverlay = new Overlay({
        element: infoElement,
        offset: [15, 15],
        stopEvent: false

      var displayCountryInfo = function(coordinate) {
        var viewResolution = /** @type {number} */ (view.getResolution());
        gridSource.forDataAtCoordinateAndResolution(coordinate, viewResolution,
          function(data) {
            // If you want to use the template from the TileJSON,
            //  load the mustache.js library separately and call
            //  info.innerHTML = Mustache.render(gridSource.getTemplate(), data);
            mapElement.style.cursor = data ? 'pointer' : '';
            if (data) {
              flagElement.src = 'data:image/png;base64,' + data['flag_png'];
              nameElement.innerHTML = data['admin'];
            infoOverlay.setPosition(data ? coordinate : undefined);

      map.on('pointermove', function(evt) {
        if (evt.dragging) {
        var coordinate = map.getEventCoordinate(evt.originalEvent);

      map.on('click', function(evt) {