Heatmaps

by grant

HTML

<script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
<script src="https://maps.googleapis.com/maps/api/js"></script>
<script src="https://maps.googleapis.com/maps/api/js?v=3.exp&amp;sensor=false&amp;libraries=visualization"></script>
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Google Maps JavaScript API v3 Example: Heatmap Layer</title>
   
    
  </head>

  <body onload="initialize()">
    <div id="map_canvas" style="height: 600px; width: 800px;"></div>
    <div id="sidebar">
      <button onclick="toggleHeatmap()">Toggle Heatmap</button>
      <button onclick="changeGradient()">Change gradient</button>
      <button onclick="changeRadius()">Change radius</button>
      <button onclick="changeOpacity()">Change opacity</button>  
    </div>
  </body>
</html>

CSS

/* Always set the map height explicitly to define the size of the div
       * element that contains the map. */
#map {
  height: 90%;
}

/* Optional: Makes the sample page fill the window. */
html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
}

#floating-panel {
  position: absolute;
  top: 10px;
  left: 25%;
  z-index: 5;
  background-color: #fff;
  padding: 5px;
  border: 1px solid #999;
  text-align: center;
  font-family: "Roboto", "sans-serif";
  line-height: 30px;
  padding-left: 10px;
}

#floating-panel {
  background-color: #fff;
  border: 1px solid #999;
  left: 25%;
  padding: 5px;
  position: absolute;
  top: 10px;
  z-index: 5;
}

JavaScript

// Adding Data Points
      var map, pointarray, heatmap;

      var taxiData = [
  {location: new google.maps.LatLng(37.782, -122.447), weight: 30},
  new google.maps.LatLng(37.782, -122.445),
  {location: new google.maps.LatLng(37.782, -122.443), weight: 2},
  {location: new google.maps.LatLng(37.782, -122.441), weight: 3},
  {location: new google.maps.LatLng(37.782, -122.439), weight: 2},
  new google.maps.LatLng(37.782, -122.437),
  {location: new google.maps.LatLng(37.782, -122.435), weight: 0.5},

  {location: new google.maps.LatLng(37.785, -122.447), weight: 3},
  {location: new google.maps.LatLng(37.785, -122.445), weight: 2},
  new google.maps.LatLng(37.785, -122.443),
  {location: new google.maps.LatLng(37.785, -122.441), weight: 0.5},
  new google.maps.LatLng(37.785, -122.439),
  {location: new google.maps.LatLng(37.785, -122.437), weight: 2},
  {location: new google.maps.LatLng(37.785, -122.435), weight: 10}
];

      function initialize() {
        var mapOptions = {
          zoom: 13,
          center: new google.maps.LatLng(37.774546, -122.433523),
          mapTypeId: google.maps.MapTypeId.SATELLITE
        };

        map = new google.maps.Map(document.getElementById('map_canvas'),
            mapOptions);

        pointArray = new google.maps.MVCArray(taxiData);

        heatmap = new google.maps.visualization.HeatmapLayer({
          data: pointArray
        });

        heatmap.setMap(map);
      }

      function toggleHeatmap() {
        heatmap.setMap(heatmap.getMap() ? null : map);
      }

      function changeGradient() {
        var gradient = [
          'rgba(0, 255, 255, 0)',
          'rgba(0, 255, 255, 1)',
          'rgba(0, 191, 255, 1)',
          'rgba(0, 127, 255, 1)',
          'rgba(0, 63, 255, 1)',
          'rgba(0, 0, 255, 1)',
          'rgba(0, 0, 223, 1)',
          'rgba(0, 0, 191, 1)',
          'rgba(0, 0, 159, 1)',
          'rgba(0, 0, 127, 1)',
          'rgba(63, 0, 91, 1)',
          'rgba(127, 0, 63, 1)',
   ...