Earthquakes Heatmap

This example uses OpenLayers v4.0.1. The latest is v.

#### Earthquakes Heatmap

radius size blur size

Demonstrates the use of a heatmap layer.

This example parses a KML file and renders the features as a `ol.layer.Heatmap` layer.

Related API documentation:

- ol.Map
,
- ol.View
,
- ol.format.KML
,
- ol.layer.Heatmap
,
- ol.layer.Tile
,
- ol.source.Stamen
,
- ol.source.Vector

Copy Edit
Earthquakes Heatmap Demonstrates the use of a heatmap layer. var blur = document.getElementById('blur'); var radius = document.getElementById('radius'); var vector = new ol.layer.Heatmap({ source: new ol.source.Vector({ url: 'https://openlayers.org/en/v4.0.1/examples/data/kml/2012_Earthquakes_Mag5.kml', format: new ol.format.KML({ extractStyles: false }) }), blur: parseInt(blur.value, 10), radius: parseInt(radius.value, 10) }); vector.getSource().on('addfeature', function(event) { // 2012_Earthquakes_Mag5.kml stores the magnitude of each earthquake in a // standards-violating <magnitude> tag in each Placemark. We extract it from // the Placemark's name instead. var name = event.feature.get('name'); var magnitude = parseFloat(name.substr(2)); event.feature.set('weight', magnitude - 5); }); var raster = new ol.layer.Tile({ source: new ol.source.Stamen({ layer: 'toner' }) }); var map = new ol.Map({ layers: [raster, vector], target: 'map', view: new ol.View({ center: [0, 0], zoom: 2 }) }); blur.addEventListener('input', function() { vector.setBlur(parseInt(blur.value, 10)); }); radius.addEventListener('input', function() { vector.setRadius(parseInt(radius.value, 10)); }); <div id="map" class="map"></div> <form> <label>radius size</label> <input id="radius" type="range" min="1" max="50" step="1" value="5"/> <label>blur size</label> <input id="blur" type="range" min="1" max="50" step="1" value="15"/> </form>

    <!DOCTYPE html>
    <html>
      <head>
        <title>Earthquakes Heatmap</title>
        <link rel="stylesheet" href="https://openlayers.org/en/v4.0.1/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>
        <script src="https://openlayers.org/en/v4.0.1/build/ol.js"></script>
      </head>
      <body>
        <div id="map" class="map"></div>
        <form>
          <label>radius size</label>
          <input id="radius" type="range" min="1" max="50" step="1" value="5"/>
          <label>blur size</label>
          <input id="blur" type="range" min="1" max="50" step="1" value="15"/>
        </form>
        <script>
          var blur = document.getElementById('blur');
          var radius = document.getElementById('radius');

          var vector = new ol.layer.Heatmap({
            source: new ol.source.Vector({
              url: 'https://openlayers.org/en/v4.0.1/examples/data/kml/2012_Earthquakes_Mag5.kml',
              format: new ol.format.KML({
                extractStyles: false
              })
            }),
            blur: parseInt(blur.value, 10),
            radius: parseInt(radius.value, 10)
          });

          vector.getSource().on('addfeature', function(event) {
            // 2012_Earthquakes_Mag5.kml stores the magnitude of each earthquake in a
            // standards-violating <magnitude> tag in each Placemark.  We extract it from
            // the Placemark's name instead.
            var name = event.feature.get('name');
            var magnitude = parseFloat(name.substr(2));
            event.feature.set('weight', magnitude - 5);
          });

          var raster = new ol.layer.Tile({
            source: new ol.source.Stamen({
              layer: 'toner'
            })
          });

          var map = new ol.Map({
            layers: [raster, vector],
            target: 'map',
            view: new ol.View({
              center: [0, 0],
              zoom: 2
            })
          });

          blur.addEventListener('input', function() {
            vector.setBlur(parseInt(blur.value, 10));
          });

          radius.addEventListener('input', function() {
            vector.setRadius(parseInt(radius.value, 10));
          });
        </script>
      </body>
    </html>