This example uses a tile overlay MapType
to overlay the map's tile
coordinates on top of the default map tiles.
Read the documentation.
TypeScript
/* * 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. */ class CoordMapType implements google.maps.MapType { tileSize: google.maps.Size; alt: string|null = null; maxZoom: number = 17; minZoom: number = 0; name: string|null = null; projection: google.maps.Projection|null = null; radius: number = 6378137; constructor(tileSize: google.maps.Size) { this.tileSize = tileSize; } getTile( coord: google.maps.Point, zoom: number, ownerDocument: Document ): HTMLElement { const div = ownerDocument.createElement("div"); div.innerHTML = String(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; } releaseTile(tile: Element): void {} } function initMap(): void { const map = new google.maps.Map( document.getElementById("map") as HTMLElement, { 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. const coordMapType = new CoordMapType(new google.maps.Size(256, 256)) map.overlayMapTypes.insertAt( 0, coordMapType ); } declare global { interface Window { initMap: () => void; } } window.initMap = initMap;
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. */ class CoordMapType { tileSize; alt = null; maxZoom = 17; minZoom = 0; name = null; projection = null; radius = 6378137; constructor(tileSize) { this.tileSize = tileSize; } getTile(coord, zoom, ownerDocument) { const div = ownerDocument.createElement("div"); div.innerHTML = String(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; } releaseTile(tile) {} } function initMap() { const 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. const coordMapType = new CoordMapType(new google.maps.Size(256, 256)); map.overlayMapTypes.insertAt(0, coordMapType); } window.initMap = initMap;
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> <head> <title>Overlay Map Types</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>
Try Sample
Clone Sample
Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.
git clone -b sample-maptype-overlay 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
.
git checkout sample-SAMPLE_NAME
npm i
npm start