TileUTFGrid example

This example shows how to read data from a TileUTFGrid layer.

Point to a country to see its name and flag.

Tiles made with TileMill. Hosting on MapBox.com or with open-source TileServer.

utfgrid, tileutfgrid, tilejson
<!DOCTYPE html>
<html>
<head>
<title>TileUTFGrid example</title>
<script src="https://code.jquery.com/jquery-1.11.2.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="http://openlayers.org/en/v3.9.0/css/ol.css" type="text/css">
<script src="http://openlayers.org/en/v3.9.0/build/ol.js"></script>

<style>
#country-name {
  color: black;
  font-size: 12pt;
  font-weight: bold;
  text-shadow: white 0.1em 0.1em 0.2em;
}

</style>
</head>
<body>
<div class="container-fluid">

<div class="row-fluid">
  <div class="span12">
    <div id="map" class="map"></div>
  </div>
</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="" />
  </div>
</div>

</div>
<script>
var mapLayer = new ol.layer.Tile({
  source: new ol.source.TileJSON({
    url: 'http://api.tiles.mapbox.com/v3/mapbox.geography-class.json'
  })
});

var gridSource = new ol.source.TileUTFGrid({
  url: 'http://api.tiles.mapbox.com/v3/mapbox.geography-class.json'
});

var gridLayer = new ol.layer.Tile({source: gridSource});

var view = new ol.View({
  center: [0, 0],
  zoom: 1
});

var mapElement = document.getElementById('map');
var map = new ol.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 ol.Overlay({
  element: infoElement,
  offset: [15, 15],
  stopEvent: false
});
map.addOverlay(infoOverlay);

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) {
          /* jshint -W069 */
          flagElement.src = 'data:image/png;base64,' + data['flag_png'];
          nameElement.innerHTML = data['admin'];
          /* jshint +W069 */
        }
        infoOverlay.setPosition(data ? coordinate : undefined);
      });
};

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

map.on('click', function(evt) {
  displayCountryInfo(evt.coordinate);
});

</script>
</body>
</html>