/** 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.*/classCoordMapTypeimplementsgoogle.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{constdiv=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";returndiv;}releaseTile(tile:Element):void{}}functioninitMap():void{constmap=newgoogle.maps.Map(document.getElementById("map")asHTMLElement,{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.constcoordMapType=newCoordMapType(newgoogle.maps.Size(256,256))map.overlayMapTypes.insertAt(0,coordMapType);}declareglobal{interfaceWindow{initMap:()=>void;}}window.initMap=initMap;
/** 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.*/classCoordMapType{tileSize;alt=null;maxZoom=17;minZoom=0;name=null;projection=null;radius=6378137;constructor(tileSize){this.tileSize=tileSize;}getTile(coord,zoom,ownerDocument){constdiv=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";returndiv;}releaseTile(tile){}}functioninitMap(){constmap=newgoogle.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.constcoordMapType=newCoordMapType(newgoogle.maps.Size(256,256));map.overlayMapTypes.insertAt(0,coordMapType);}window.initMap=initMap;
/** 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>
<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>
Git and Node.js are required to run this sample locally. Follow theseinstructionsto install Node.js and NPM. The following commands clone, install dependencies and start the sample application.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThis example demonstrates how to overlay a grid of tile coordinates on top of the base map using a custom \u003ccode\u003eMapType\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe overlay showcases the coordinate system of map tiles, with the origin at the northwest corner.\u003c/p\u003e\n"],["\u003cp\u003eThe tile coordinates update dynamically as the user pans and zooms the map.\u003c/p\u003e\n"],["\u003cp\u003eThe sample provides code in TypeScript, JavaScript, CSS, and HTML to implement the overlay.\u003c/p\u003e\n"]]],[],null,["This example uses a tile overlay `MapType` to overlay the map's tile\ncoordinates on top of the default map tiles.\n\nRead the\n[documentation](/maps/documentation/javascript/maptypes#OverlayMapTypes). \n\nTypeScript \n\n```typescript\n/*\n * This demo illustrates the coordinate system used to display map tiles in the\n * API.\n *\n * Tiles in Google Maps are numbered from the same origin as that for\n * pixels. For Google's implementation of the Mercator projection, the origin\n * tile is always at the northwest corner of the map, with x values increasing\n * from west to east and y values increasing from north to south.\n *\n * Try panning and zooming the map to see how the coordinates change.\n */\n\nclass CoordMapType implements google.maps.MapType {\n tileSize: google.maps.Size;\n alt: string|null = null;\n maxZoom: number = 17;\n minZoom: number = 0;\n name: string|null = null;\n projection: google.maps.Projection|null = null;\n radius: number = 6378137;\n\n constructor(tileSize: google.maps.Size) {\n this.tileSize = tileSize;\n }\n getTile(\n coord: google.maps.Point,\n zoom: number,\n ownerDocument: Document\n ): HTMLElement {\n const div = ownerDocument.createElement(\"div\");\n\n div.innerHTML = String(coord);\n div.style.width = this.tileSize.width + \"px\";\n div.style.height = this.tileSize.height + \"px\";\n div.style.fontSize = \"10\";\n div.style.borderStyle = \"solid\";\n div.style.borderWidth = \"1px\";\n div.style.borderColor = \"#AAAAAA\";\n return div;\n }\n releaseTile(tile: Element): void {}\n}\n\nfunction initMap(): void {\n const map = new google.maps.Map(\n document.getElementById(\"map\") as HTMLElement,\n {\n zoom: 10,\n center: { lat: 41.85, lng: -87.65 },\n }\n );\n\n // Insert this overlay map type as the first overlay map type at\n // position 0. Note that all overlay map types appear on top of\n // their parent base map.\n const coordMapType = new CoordMapType(new google.maps.Size(256, 256))\n map.overlayMapTypes.insertAt(\n 0,\n coordMapType\n );\n}\n\ndeclare global {\n interface Window {\n initMap: () =\u003e void;\n }\n}\nwindow.initMap = initMap;https://github.com/googlemaps/js-samples/blob/2683f7366fb27829401945d2a7e27d77ed2df8e5/samples/maptype-overlay/index.ts#L8-L75\n```\n| **Note:** Read the [guide](/maps/documentation/javascript/using-typescript) on using TypeScript and Google Maps.\n\nJavaScript \n\n```javascript\n/*\n * This demo illustrates the coordinate system used to display map tiles in the\n * API.\n *\n * Tiles in Google Maps are numbered from the same origin as that for\n * pixels. For Google's implementation of the Mercator projection, the origin\n * tile is always at the northwest corner of the map, with x values increasing\n * from west to east and y values increasing from north to south.\n *\n * Try panning and zooming the map to see how the coordinates change.\n */\nclass CoordMapType {\n tileSize;\n alt = null;\n maxZoom = 17;\n minZoom = 0;\n name = null;\n projection = null;\n radius = 6378137;\n constructor(tileSize) {\n this.tileSize = tileSize;\n }\n getTile(coord, zoom, ownerDocument) {\n const div = ownerDocument.createElement(\"div\");\n\n div.innerHTML = String(coord);\n div.style.width = this.tileSize.width + \"px\";\n div.style.height = this.tileSize.height + \"px\";\n div.style.fontSize = \"10\";\n div.style.borderStyle = \"solid\";\n div.style.borderWidth = \"1px\";\n div.style.borderColor = \"#AAAAAA\";\n return div;\n }\n releaseTile(tile) {}\n}\n\nfunction initMap() {\n const map = new google.maps.Map(document.getElementById(\"map\"), {\n zoom: 10,\n center: { lat: 41.85, lng: -87.65 },\n });\n // Insert this overlay map type as the first overlay map type at\n // position 0. Note that all overlay map types appear on top of\n // their parent base map.\n const coordMapType = new CoordMapType(new google.maps.Size(256, 256));\n\n map.overlayMapTypes.insertAt(0, coordMapType);\n}\n\nwindow.initMap = initMap;https://github.com/googlemaps/js-samples/blob/2683f7366fb27829401945d2a7e27d77ed2df8e5/dist/samples/maptype-overlay/docs/index.js#L7-L57\n```\n| **Note:** The JavaScript is compiled from the TypeScript snippet.\n\nCSS \n\n```css\n/* \n * Always set the map height explicitly to define the size of the div element\n * that contains the map. \n */\n#map {\n height: 100%;\n}\n\n/* \n * Optional: Makes the sample page fill the window. \n */\nhtml,\nbody {\n height: 100%;\n margin: 0;\n padding: 0;\n}\nhttps://github.com/googlemaps/js-samples/blob/2683f7366fb27829401945d2a7e27d77ed2df8e5/dist/samples/maptype-overlay/docs/style.css#L7-L24\n```\n\nHTML \n\n```html\n\u003chtml\u003e\n \u003chead\u003e\n \u003ctitle\u003eOverlay Map Types\u003c/title\u003e\n\n \u003clink rel=\"stylesheet\" type=\"text/css\" href=\"./style.css\" /\u003e\n \u003cscript type=\"module\" src=\"./index.js\"\u003e\u003c/script\u003e\n \u003c/head\u003e\n \u003cbody\u003e\n \u003cdiv id=\"map\"\u003e\u003c/div\u003e\n\n \u003c!-- \n The `defer` attribute causes the script to execute after the full HTML\n document has been parsed. For non-blocking uses, avoiding race conditions,\n and consistent behavior across browsers, consider loading using Promises. See\n https://developers.google.com/maps/documentation/javascript/load-maps-js-api\n for more information.\n --\u003e\n \u003cscript\n src=\"https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=weekly\"\n defer\n \u003e\u003c/script\u003e\n \u003c/body\u003e\n\u003c/html\u003ehttps://github.com/googlemaps/js-samples/blob/2683f7366fb27829401945d2a7e27d77ed2df8e5/dist/samples/maptype-overlay/docs/index.html#L8-L30\n```\n\nTry Sample \n[JSFiddle.net](https://jsfiddle.net/gh/get/library/pure/googlemaps/js-samples/tree/master/dist/samples/maptype-overlay/jsfiddle) [Google Cloud Shell](https://ssh.cloud.google.com/cloudshell/editor?cloudshell_git_repo=https%3A%2F%2Fgithub.com%2Fgooglemaps%2Fjs-samples&cloudshell_git_branch=sample-maptype-overlay&cloudshell_tutorial=cloud_shell_instructions.md&cloudshell_workspace=.)\n\nClone Sample\n\n\nGit 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. \n\n git clone -b sample-maptype-overlay https://github.com/googlemaps/js-samples.git\n cd js-samples\n npm i\n npm start\n\n\nOther samples can be tried by switching to any branch beginning with `sample-`\u003cvar translate=\"no\"\u003eSAMPLE_NAME\u003c/var\u003e. \n\n git checkout sample-\u003cvar translate=\"no\"\u003e\u003cspan class=\"devsite-syntax-nx\"\u003eSAMPLE_NAME\u003c/span\u003e\u003c/var\u003e\n npm i\n npm start"]]
