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Overlay Map Types

This example uses a tile overlay MapType to overlay the map's tile coordinates on top of the default map tiles.

Read the documentation.

JavaScript

/*
 * This demo illustrates the coordinate system used to display map tiles in the
 * API.
 *
 * Tiles in Google Maps are numbered from the same origin as that for
 * pixels. For Google's implementation of the Mercator projection, the origin
 * tile is always at the northwest corner of the map, with x values increasing
 * from west to east and y values increasing from north to south.
 *
 * Try panning and zooming the map to see how the coordinates change.
 */

/** @constructor */
function CoordMapType(tileSize) {
  this.tileSize = tileSize;
}

CoordMapType.prototype.getTile = function(coord, zoom, ownerDocument) {
  var div = ownerDocument.createElement("div");
  div.innerHTML = coord;
  div.style.width = this.tileSize.width + "px";
  div.style.height = this.tileSize.height + "px";
  div.style.fontSize = "10";
  div.style.borderStyle = "solid";
  div.style.borderWidth = "1px";
  div.style.borderColor = "#AAAAAA";
  return div;
};

function initMap() {
  var map = new google.maps.Map(document.getElementById("map"), {
    zoom: 10,
    center: { lat: 41.85, lng: -87.65 }
  });

  // Insert this overlay map type as the first overlay map type at
  // position 0. Note that all overlay map types appear on top of
  // their parent base map.
  map.overlayMapTypes.insertAt(
    0,
    new CoordMapType(new google.maps.Size(256, 256))
  );
}

CSS

/* 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;
}

HTML

<!DOCTYPE html>
<html>
  <head>
    <title>Overlay Map Types</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <script
      src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap&libraries=&v=weekly"
      defer
    ></script>
    <link rel="stylesheet" type="text/css" href="./style.css" />
    <script src="./app.js"></script>
  </head>
  <body>
    <div id="map"></div>
  </body>
</html>

All

<!DOCTYPE html>
<html>
  <head>
    <title>Overlay Map Types</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <script
      src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap&libraries=&v=weekly"
      defer
    ></script>
    <style type="text/css">
      /* 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>
      (function(exports) {
        "use strict";

        /*
         * This demo illustrates the coordinate system used to display map tiles in the
         * API.
         *
         * Tiles in Google Maps are numbered from the same origin as that for
         * pixels. For Google's implementation of the Mercator projection, the origin
         * tile is always at the northwest corner of the map, with x values increasing
         * from west to east and y values increasing from north to south.
         *
         * Try panning and zooming the map to see how the coordinates change.
         */

        /** @constructor */
        function CoordMapType(tileSize) {
          this.tileSize = tileSize;
        }

        CoordMapType.prototype.getTile = function(coord, zoom, ownerDocument) {
          var div = ownerDocument.createElement("div");
          div.innerHTML = coord;
          div.style.width = this.tileSize.width + "px";
          div.style.height = this.tileSize.height + "px";
          div.style.fontSize = "10";
          div.style.borderStyle = "solid";
          div.style.borderWidth = "1px";
          div.style.borderColor = "#AAAAAA";
          return div;
        };

        function initMap() {
          var map = new google.maps.Map(document.getElementById("map"), {
            zoom: 10,
            center: {
              lat: 41.85,
              lng: -87.65
            }
          }); // Insert this overlay map type as the first overlay map type at
          // position 0. Note that all overlay map types appear on top of
          // their parent base map.

          map.overlayMapTypes.insertAt(
            0,
            new CoordMapType(new google.maps.Size(256, 256))
          );
        }

        exports.CoordMapType = CoordMapType;
        exports.initMap = initMap;
      })((this.window = this.window || {}));
    </script>
  </head>
  <body>
    <div id="map"></div>
  </body>
</html>
(function(exports) { "use strict"; /* * This demo illustrates the coordinate system used to display map tiles in the * API. * * Tiles in Google Maps are numbered from the same origin as that for * pixels. For Google's implementation of the Mercator projection, the origin * tile is always at the northwest corner of the map, with x values increasing * from west to east and y values increasing from north to south. * * Try panning and zooming the map to see how the coordinates change. */ /** @constructor */ function CoordMapType(tileSize) { this.tileSize = tileSize; } CoordMapType.prototype.getTile = function(coord, zoom, ownerDocument) { var div = ownerDocument.createElement("div"); div.innerHTML = coord; div.style.width = this.tileSize.width + "px"; div.style.height = this.tileSize.height + "px"; div.style.fontSize = "10"; div.style.borderStyle = "solid"; div.style.borderWidth = "1px"; div.style.borderColor = "#AAAAAA"; return div; }; function initMap() { var map = new google.maps.Map(document.getElementById("map"), { zoom: 10, center: { lat: 41.85, lng: -87.65 } }); // Insert this overlay map type as the first overlay map type at // position 0. Note that all overlay map types appear on top of // their parent base map. map.overlayMapTypes.insertAt( 0, new CoordMapType(new google.maps.Size(256, 256)) ); } exports.CoordMapType = CoordMapType; exports.initMap = initMap; })((this.window = this.window || {}));
/* 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; }
<!DOCTYPE html> <html> <head> <title>Overlay Map Types</title> <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script> <script src="https://maps.googleapis.com/maps/api/js?key=&callback=initMap&libraries=&v=weekly" defer ></script> <!-- jsFiddle will insert css and js --> </head> <body> <div id="map"></div> </body> </html>