// This example adds an animated symbol to a polyline.functioninitMap():void{constmap=newgoogle.maps.Map(document.getElementById("map")asHTMLElement,{center:{lat:20.291,lng:153.027},zoom:6,mapTypeId:"terrain",});// Define the symbol, using one of the predefined paths ('CIRCLE')// supplied by the Google Maps JavaScript API.constlineSymbol={path:google.maps.SymbolPath.CIRCLE,scale:8,strokeColor:"#393",};// Create the polyline and add the symbol to it via the 'icons' property.constline=newgoogle.maps.Polyline({path:[{lat:22.291,lng:153.027},{lat:18.291,lng:153.027},],icons:[{icon:lineSymbol,offset:"100%",},],map:map,});animateCircle(line);}// Use the DOM setInterval() function to change the offset of the symbol// at fixed intervals.functionanimateCircle(line:google.maps.Polyline){letcount=0;window.setInterval(()=>{count=(count+1)%200;consticons=line.get("icons");icons[0].offset=count/2+"%";line.set("icons",icons);},20);}declareglobal{interfaceWindow{initMap:()=>void;}}window.initMap=initMap;
// This example adds an animated symbol to a polyline.functioninitMap(){constmap=newgoogle.maps.Map(document.getElementById("map"),{center:{lat:20.291,lng:153.027},zoom:6,mapTypeId:"terrain",});// Define the symbol, using one of the predefined paths ('CIRCLE')// supplied by the Google Maps JavaScript API.constlineSymbol={path:google.maps.SymbolPath.CIRCLE,scale:8,strokeColor:"#393",};// Create the polyline and add the symbol to it via the 'icons' property.constline=newgoogle.maps.Polyline({path:[{lat:22.291,lng:153.027},{lat:18.291,lng:153.027},],icons:[{icon:lineSymbol,offset:"100%",},],map:map,});animateCircle(line);}// Use the DOM setInterval() function to change the offset of the symbol// at fixed intervals.functionanimateCircle(line){letcount=0;window.setInterval(()=>{count=(count+1)%200;consticons=line.get("icons");icons[0].offset=count/2+"%";line.set("icons",icons);},20);}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>Animating Symbols</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 animate a symbol, specifically a circle, along a polyline on a Google Map.\u003c/p\u003e\n"],["\u003cp\u003eThe animation is achieved by repeatedly adjusting the symbol's offset position using \u003ccode\u003esetInterval\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eA predefined circle symbol is used, and its appearance is customized with scale and stroke color.\u003c/p\u003e\n"],["\u003cp\u003eThe polyline path and initial map settings are defined within the \u003ccode\u003einitMap\u003c/code\u003e function.\u003c/p\u003e\n"],["\u003cp\u003eThe sample provides both TypeScript and JavaScript code snippets for implementation.\u003c/p\u003e\n"]]],["This code animates a circle symbol along a polyline on a Google Map. It initializes a map and defines a circle symbol. A polyline is created with two coordinates, and the circle symbol is added to it as an icon. The `animateCircle` function uses `setInterval` to change the symbol's offset, creating movement. CSS sets the map's height, and HTML structures the page with the map and scripts. The document also includes links to JSFiddle and Cloud Shell for demonstration, and instructions to clone and run the sample.\n"],null,["This example adds an animated symbol to a polyline.\n\nRead the [documentation](/maps/documentation/javascript/symbols#animate). \n\nTypeScript \n\n```typescript\n// This example adds an animated symbol to a polyline.\n\nfunction initMap(): void {\n const map = new google.maps.Map(\n document.getElementById(\"map\") as HTMLElement,\n {\n center: { lat: 20.291, lng: 153.027 },\n zoom: 6,\n mapTypeId: \"terrain\",\n }\n );\n\n // Define the symbol, using one of the predefined paths ('CIRCLE')\n // supplied by the Google Maps JavaScript API.\n const lineSymbol = {\n path: google.maps.SymbolPath.CIRCLE,\n scale: 8,\n strokeColor: \"#393\",\n };\n\n // Create the polyline and add the symbol to it via the 'icons' property.\n const line = new google.maps.Polyline({\n path: [\n { lat: 22.291, lng: 153.027 },\n { lat: 18.291, lng: 153.027 },\n ],\n icons: [\n {\n icon: lineSymbol,\n offset: \"100%\",\n },\n ],\n map: map,\n });\n\n animateCircle(line);\n}\n\n// Use the DOM setInterval() function to change the offset of the symbol\n// at fixed intervals.\nfunction animateCircle(line: google.maps.Polyline) {\n let count = 0;\n\n window.setInterval(() =\u003e {\n count = (count + 1) % 200;\n\n const icons = line.get(\"icons\");\n\n icons[0].offset = count / 2 + \"%\";\n line.set(\"icons\", icons);\n }, 20);\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/overlay-symbol-animate/index.ts#L8-L66\n```\n| **Note:** Read the [guide](/maps/documentation/javascript/using-typescript) on using TypeScript and Google Maps.\n\nJavaScript \n\n```javascript\n// This example adds an animated symbol to a polyline.\nfunction initMap() {\n const map = new google.maps.Map(document.getElementById(\"map\"), {\n center: { lat: 20.291, lng: 153.027 },\n zoom: 6,\n mapTypeId: \"terrain\",\n });\n // Define the symbol, using one of the predefined paths ('CIRCLE')\n // supplied by the Google Maps JavaScript API.\n const lineSymbol = {\n path: google.maps.SymbolPath.CIRCLE,\n scale: 8,\n strokeColor: \"#393\",\n };\n // Create the polyline and add the symbol to it via the 'icons' property.\n const line = new google.maps.Polyline({\n path: [\n { lat: 22.291, lng: 153.027 },\n { lat: 18.291, lng: 153.027 },\n ],\n icons: [\n {\n icon: lineSymbol,\n offset: \"100%\",\n },\n ],\n map: map,\n });\n\n animateCircle(line);\n}\n\n// Use the DOM setInterval() function to change the offset of the symbol\n// at fixed intervals.\nfunction animateCircle(line) {\n let count = 0;\n\n window.setInterval(() =\u003e {\n count = (count + 1) % 200;\n\n const icons = line.get(\"icons\");\n\n icons[0].offset = count / 2 + \"%\";\n line.set(\"icons\", icons);\n }, 20);\n}\n\nwindow.initMap = initMap;https://github.com/googlemaps/js-samples/blob/2683f7366fb27829401945d2a7e27d77ed2df8e5/dist/samples/overlay-symbol-animate/docs/index.js#L7-L54\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/overlay-symbol-animate/docs/style.css#L7-L24\n```\n\nHTML \n\n```html\n\u003chtml\u003e\n \u003chead\u003e\n \u003ctitle\u003eAnimating Symbols\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/overlay-symbol-animate/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/overlay-symbol-animate/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-overlay-symbol-animate&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-overlay-symbol-animate 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"]]
