Adding a Custom Overlay

Read the documentation or view this example full screen.

// This example creates a custom overlay called USGSOverlay, containing
// a U.S. Geological Survey (USGS) image of the relevant area on the map.

// Set the custom overlay object's prototype to a new instance
// of OverlayView. In effect, this will subclass the overlay class therefore
// it's simpler to load the API synchronously, using
// google.maps.event.addDomListener().
// Note that we set the prototype to an instance, rather than the
// parent class itself, because we do not wish to modify the parent class.

var overlay;
USGSOverlay.prototype = new google.maps.OverlayView();

// Initialize the map and the custom overlay.

function initMap() {
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 11,
    center: {lat: 62.323907, lng: -150.109291},
    mapTypeId: 'satellite'
  });

  var bounds = new google.maps.LatLngBounds(
      new google.maps.LatLng(62.281819, -150.287132),
      new google.maps.LatLng(62.400471, -150.005608));

  // The photograph is courtesy of the U.S. Geological Survey.
  var srcImage = 'https://developers.google.com/maps/documentation/' +
      'javascript/examples/full/images/talkeetna.png';

  // The custom USGSOverlay object contains the USGS image,
  // the bounds of the image, and a reference to the map.
  overlay = new USGSOverlay(bounds, srcImage, map);
}

/** @constructor */
function USGSOverlay(bounds, image, map) {

  // Initialize all properties.
  this.bounds_ = bounds;
  this.image_ = image;
  this.map_ = map;

  // Define a property to hold the image's div. We'll
  // actually create this div upon receipt of the onAdd()
  // method so we'll leave it null for now.
  this.div_ = null;

  // Explicitly call setMap on this overlay.
  this.setMap(map);
}

/**
 * onAdd is called when the map's panes are ready and the overlay has been
 * added to the map.
 */
USGSOverlay.prototype.onAdd = function() {

  var div = document.createElement('div');
  div.style.borderStyle = 'none';
  div.style.borderWidth = '0px';
  div.style.position = 'absolute';

  // Create the img element and attach it to the div.
  var img = document.createElement('img');
  img.src = this.image_;
  img.style.width = '100%';
  img.style.height = '100%';
  img.style.position = 'absolute';
  div.appendChild(img);

  this.div_ = div;

  // Add the element to the "overlayLayer" pane.
  var panes = this.getPanes();
  panes.overlayLayer.appendChild(div);
};

USGSOverlay.prototype.draw = function() {

  // We use the south-west and north-east
  // coordinates of the overlay to peg it to the correct position and size.
  // To do this, we need to retrieve the projection from the overlay.
  var overlayProjection = this.getProjection();

  // Retrieve the south-west and north-east coordinates of this overlay
  // in LatLngs and convert them to pixel coordinates.
  // We'll use these coordinates to resize the div.
  var sw = overlayProjection.fromLatLngToDivPixel(this.bounds_.getSouthWest());
  var ne = overlayProjection.fromLatLngToDivPixel(this.bounds_.getNorthEast());

  // Resize the image's div to fit the indicated dimensions.
  var div = this.div_;
  div.style.left = sw.x + 'px';
  div.style.top = ne.y + 'px';
  div.style.width = (ne.x - sw.x) + 'px';
  div.style.height = (sw.y - ne.y) + 'px';
};

// The onRemove() method will be called automatically from the API if
// we ever set the overlay's map property to 'null'.
USGSOverlay.prototype.onRemove = function() {
  this.div_.parentNode.removeChild(this.div_);
  this.div_ = null;
};

google.maps.event.addDomListener(window, 'load', initMap);

<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 src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk"></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>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <title>Adding a Custom Overlay</title>
    <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>
    <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY"></script>
    <script>
      // This example creates a custom overlay called USGSOverlay, containing
      // a U.S. Geological Survey (USGS) image of the relevant area on the map.

      // Set the custom overlay object's prototype to a new instance
      // of OverlayView. In effect, this will subclass the overlay class therefore
      // it's simpler to load the API synchronously, using
      // google.maps.event.addDomListener().
      // Note that we set the prototype to an instance, rather than the
      // parent class itself, because we do not wish to modify the parent class.

      var overlay;
      USGSOverlay.prototype = new google.maps.OverlayView();

      // Initialize the map and the custom overlay.

      function initMap() {
        var map = new google.maps.Map(document.getElementById('map'), {
          zoom: 11,
          center: {lat: 62.323907, lng: -150.109291},
          mapTypeId: 'satellite'
        });

        var bounds = new google.maps.LatLngBounds(
            new google.maps.LatLng(62.281819, -150.287132),
            new google.maps.LatLng(62.400471, -150.005608));

        // The photograph is courtesy of the U.S. Geological Survey.
        var srcImage = 'https://developers.google.com/maps/documentation/' +
            'javascript/examples/full/images/talkeetna.png';

        // The custom USGSOverlay object contains the USGS image,
        // the bounds of the image, and a reference to the map.
        overlay = new USGSOverlay(bounds, srcImage, map);
      }

      /** @constructor */
      function USGSOverlay(bounds, image, map) {

        // Initialize all properties.
        this.bounds_ = bounds;
        this.image_ = image;
        this.map_ = map;

        // Define a property to hold the image's div. We'll
        // actually create this div upon receipt of the onAdd()
        // method so we'll leave it null for now.
        this.div_ = null;

        // Explicitly call setMap on this overlay.
        this.setMap(map);
      }

      /**
       * onAdd is called when the map's panes are ready and the overlay has been
       * added to the map.
       */
      USGSOverlay.prototype.onAdd = function() {

        var div = document.createElement('div');
        div.style.borderStyle = 'none';
        div.style.borderWidth = '0px';
        div.style.position = 'absolute';

        // Create the img element and attach it to the div.
        var img = document.createElement('img');
        img.src = this.image_;
        img.style.width = '100%';
        img.style.height = '100%';
        img.style.position = 'absolute';
        div.appendChild(img);

        this.div_ = div;

        // Add the element to the "overlayLayer" pane.
        var panes = this.getPanes();
        panes.overlayLayer.appendChild(div);
      };

      USGSOverlay.prototype.draw = function() {

        // We use the south-west and north-east
        // coordinates of the overlay to peg it to the correct position and size.
        // To do this, we need to retrieve the projection from the overlay.
        var overlayProjection = this.getProjection();

        // Retrieve the south-west and north-east coordinates of this overlay
        // in LatLngs and convert them to pixel coordinates.
        // We'll use these coordinates to resize the div.
        var sw = overlayProjection.fromLatLngToDivPixel(this.bounds_.getSouthWest());
        var ne = overlayProjection.fromLatLngToDivPixel(this.bounds_.getNorthEast());

        // Resize the image's div to fit the indicated dimensions.
        var div = this.div_;
        div.style.left = sw.x + 'px';
        div.style.top = ne.y + 'px';
        div.style.width = (ne.x - sw.x) + 'px';
        div.style.height = (sw.y - ne.y) + 'px';
      };

      // The onRemove() method will be called automatically from the API if
      // we ever set the overlay's map property to 'null'.
      USGSOverlay.prototype.onRemove = function() {
        this.div_.parentNode.removeChild(this.div_);
        this.div_ = null;
      };

      google.maps.event.addDomListener(window, 'load', initMap);
    </script>
  </head>
  <body>
    <div id="map"></div>
  </body>
</html>