Demonstrates the use of a heatmap layer.
This example parses a KML file and renders the features as a ol.layer.Heatmap layer.
ol.layer.Heatmap
<!DOCTYPE html> <html> <head> <title>Earthquakes heatmap</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/3.8.1/css/ol.css" type="text/css"> <script src="http://openlayers.org/en/3.8.1/build/ol.js"></script> </head> <body> <div class="container-fluid"> <div class="row-fluid"> <div class="span12"> <div id="map" class="map"></div> </div> <div class="span4"> <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> </div> </div> </div> <script> var blur = document.getElementById('blur'); var radius = document.getElementById('radius'); var vector = new ol.layer.Heatmap({ source: new ol.source.Vector({ url: '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>