This example creates a map that displays a window with the latitude, longitude,
and world, pixel, and tile coordinates for Chicago, IL. It also shows how these
values change as the zoom level is adjusted.

Read the
[documentation](https://developers.google.com/maps/documentation/javascript/trafficlayer.md.txt#transit_layer).
<iframe src="https://geo-devrel-javascript-samples.web.app/samples/map-coordinates/app/dist/" allow="fullscreen; "></iframe>

### TypeScript

```typescript
function initMap(): void {
  const chicago = new google.maps.LatLng(41.85, -87.65);

  const map = new google.maps.Map(
    document.getElementById("map") as HTMLElement,
    {
      center: chicago,
      zoom: 3,
    }
  );

  const coordInfoWindow = new google.maps.InfoWindow();

  coordInfoWindow.setContent(createInfoWindowContent(chicago, map.getZoom()!));
  coordInfoWindow.setPosition(chicago);
  coordInfoWindow.open(map);

  map.addListener("zoom_changed", () => {
    coordInfoWindow.setContent(
      createInfoWindowContent(chicago, map.getZoom()!)
    );
    coordInfoWindow.open(map);
  });
}

const TILE_SIZE = 256;

function createInfoWindowContent(latLng: google.maps.LatLng, zoom: number) {
  const scale = 1 << zoom;

  const worldCoordinate = project(latLng);

  const pixelCoordinate = new google.maps.Point(
    Math.floor(worldCoordinate.x * scale),
    Math.floor(worldCoordinate.y * scale)
  );

  const tileCoordinate = new google.maps.Point(
    Math.floor((worldCoordinate.x * scale) / TILE_SIZE),
    Math.floor((worldCoordinate.y * scale) / TILE_SIZE)
  );

  return [
    "Chicago, IL",
    "LatLng: " + latLng,
    "Zoom level: " + zoom,
    "World Coordinate: " + worldCoordinate,
    "Pixel Coordinate: " + pixelCoordinate,
    "Tile Coordinate: " + tileCoordinate,
  ].join("<br>");
}

// The mapping between latitude, longitude and pixels is defined by the web
// mercator projection.
function project(latLng: google.maps.LatLng) {
  let siny = Math.sin((latLng.lat() * Math.PI) / 180);

  // Truncating to 0.9999 effectively limits latitude to 89.189. This is
  // about a third of a tile past the edge of the world tile.
  siny = Math.min(Math.max(siny, -0.9999), 0.9999);

  return new google.maps.Point(
    TILE_SIZE * (0.5 + latLng.lng() / 360),
    TILE_SIZE * (0.5 - Math.log((1 + siny) / (1 - siny)) / (4 * Math.PI))
  );
}

declare global {
  interface Window {
    initMap: () => void;
  }
}
window.initMap = initMap;
```

> [!NOTE]
> **Note:** Read the [guide](https://developers.google.com/maps/documentation/javascript/using-typescript.md.txt) on using TypeScript and Google Maps.

### JavaScript

```javascript
function initMap() {
  const chicago = new google.maps.LatLng(41.85, -87.65);
  const map = new google.maps.Map(document.getElementById("map"), {
    center: chicago,
    zoom: 3,
  });
  const coordInfoWindow = new google.maps.InfoWindow();

  coordInfoWindow.setContent(createInfoWindowContent(chicago, map.getZoom()));
  coordInfoWindow.setPosition(chicago);
  coordInfoWindow.open(map);
  map.addListener("zoom_changed", () => {
    coordInfoWindow.setContent(createInfoWindowContent(chicago, map.getZoom()));
    coordInfoWindow.open(map);
  });
}

const TILE_SIZE = 256;

function createInfoWindowContent(latLng, zoom) {
  const scale = 1 << zoom;
  const worldCoordinate = project(latLng);
  const pixelCoordinate = new google.maps.Point(
    Math.floor(worldCoordinate.x * scale),
    Math.floor(worldCoordinate.y * scale),
  );
  const tileCoordinate = new google.maps.Point(
    Math.floor((worldCoordinate.x * scale) / TILE_SIZE),
    Math.floor((worldCoordinate.y * scale) / TILE_SIZE),
  );
  return [
    "Chicago, IL",
    "LatLng: " + latLng,
    "Zoom level: " + zoom,
    "World Coordinate: " + worldCoordinate,
    "Pixel Coordinate: " + pixelCoordinate,
    "Tile Coordinate: " + tileCoordinate,
  ].join("<br>");
}

// The mapping between latitude, longitude and pixels is defined by the web
// mercator projection.
function project(latLng) {
  let siny = Math.sin((latLng.lat() * Math.PI) / 180);

  // Truncating to 0.9999 effectively limits latitude to 89.189. This is
  // about a third of a tile past the edge of the world tile.
  siny = Math.min(Math.max(siny, -0.9999), 0.9999);
  return new google.maps.Point(
    TILE_SIZE * (0.5 + latLng.lng() / 360),
    TILE_SIZE * (0.5 - Math.log((1 + siny) / (1 - siny)) / (4 * Math.PI)),
  );
}

window.initMap = initMap;
```

> [!NOTE]
> **Note:** The JavaScript is compiled from the TypeScript snippet.

### CSS

```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

```html
<html>
  <head>
    <title>Showing Pixel and Tile Coordinates</title>

    <link rel="stylesheet" type="text/css" href="./style.css" />
    <script type="module" src="./index.js"></script>
  </head>
  <body>
    <div id="map"></div>

    <!-- 
      The `defer` attribute causes the script to execute after the full HTML
      document has been parsed. For non-blocking uses, avoiding race conditions,
      and consistent behavior across browsers, consider loading using Promises. See
      https://developers.google.com/maps/documentation/javascript/load-maps-js-api
      for more information.
      -->
    <script
      src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=weekly"
      defer
    ></script>
  </body>
</html>
```

### Clone Sample


Git and Node.js are required to run this sample locally. Follow these [instructions](https://docs.npmjs.com/downloading-and-installing-node-js-and-npm) to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.

```javascript
  git clone -b sample-map-coordinates https://github.com/googlemaps/js-samples.git
  cd js-samples
  npm i
  npm start
```


Other samples can be tried by switching to any branch beginning with `sample-SAMPLE_NAME`.

```javascript
  git checkout sample-SAMPLE_NAME
  npm i
  npm start
```