You're all set!

To start developing, please head over to our developer documentation.

Activate the Google Maps JavaScript API

To get you started we'll guide you through the Google Developers Console to do a few things first:

  1. Create or choose a project
  2. Activate the Google Maps JavaScript API and related services
  3. Create appropriate keys
Continue

Data Layer: Dynamic Styling

Read the documentation or view this example full screen.

var map;
function initMap() {
  map = new google.maps.Map(document.getElementById('map'), {
    zoom: 4,
    center: {lat: -28, lng: 137}
  });

  // Load GeoJSON.
  map.data.loadGeoJson(
      'https://storage.googleapis.com/mapsdevsite/json/google.json');

  // Color each letter gray. Change the color when the isColorful property
  // is set to true.
  map.data.setStyle(function(feature) {
    var color = 'gray';
    if (feature.getProperty('isColorful')) {
      color = feature.getProperty('color');
    }
    return /** @type {google.maps.Data.StyleOptions} */({
      fillColor: color,
      strokeColor: color,
      strokeWeight: 2
    });
  });

  // When the user clicks, set 'isColorful', changing the color of the letters.
  map.data.addListener('click', function(event) {
    event.feature.setProperty('isColorful', true);
  });

  // When the user hovers, tempt them to click by outlining the letters.
  // Call revertStyle() to remove all overrides. This will use the style rules
  // defined in the function passed to setStyle()
  map.data.addListener('mouseover', function(event) {
    map.data.revertStyle();
    map.data.overrideStyle(event.feature, {strokeWeight: 8});
  });

  map.data.addListener('mouseout', function(event) {
    map.data.revertStyle();
  });
}
<div id="map"></div>
/* Always set the map height explicitly to define the size of the div
 * element that contains the map. */
#map {
  height: 100%;
}
/* Optional: Makes the sample page fill the window. */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}
<!-- Replace the value of the key parameter with your own API key. -->
<script async defer
src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&callback=initMap">
</script>

Try it yourself

Hover at top right of the code block to copy the code or open it in JSFiddle.

<!DOCTYPE html>
<html>
  <head>
    <title>Data Layer: Dynamic Styling</title>
    <meta name="viewport" content="initial-scale=1.0">
    <meta charset="utf-8">
    <style>
      /* Always set the map height explicitly to define the size of the div
       * element that contains the map. */
      #map {
        height: 100%;
      }
      /* Optional: Makes the sample page fill the window. */
      html, body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
    </style>
  </head>
  <body>
    <div id="map"></div>
    <script>

      var map;
      function initMap() {
        map = new google.maps.Map(document.getElementById('map'), {
          zoom: 4,
          center: {lat: -28, lng: 137}
        });

        // Load GeoJSON.
        map.data.loadGeoJson(
            'https://storage.googleapis.com/mapsdevsite/json/google.json');

        // Color each letter gray. Change the color when the isColorful property
        // is set to true.
        map.data.setStyle(function(feature) {
          var color = 'gray';
          if (feature.getProperty('isColorful')) {
            color = feature.getProperty('color');
          }
          return /** @type {google.maps.Data.StyleOptions} */({
            fillColor: color,
            strokeColor: color,
            strokeWeight: 2
          });
        });

        // When the user clicks, set 'isColorful', changing the color of the letters.
        map.data.addListener('click', function(event) {
          event.feature.setProperty('isColorful', true);
        });

        // When the user hovers, tempt them to click by outlining the letters.
        // Call revertStyle() to remove all overrides. This will use the style rules
        // defined in the function passed to setStyle()
        map.data.addListener('mouseover', function(event) {
          map.data.revertStyle();
          map.data.overrideStyle(event.feature, {strokeWeight: 8});
        });

        map.data.addListener('mouseout', function(event) {
          map.data.revertStyle();
        });
      }
    </script>
    <script async defer
    src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap">
    </script>
  </body>
</html>

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