Animating Symbols

This example adds an animated symbol to a polyline.

Read the documentation.

TypeScript

// This example adds an animated symbol to a polyline.

function initMap(): void {
  const map = new google.maps.Map(
    document.getElementById("map") as HTMLElement,
    {
      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.
  const lineSymbol = {
    path: google.maps.SymbolPath.CIRCLE,
    scale: 8,
    strokeColor: "#393",
  };

  // Create the polyline and add the symbol to it via the 'icons' property.
  const line = new google.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.
function animateCircle(line: google.maps.Polyline) {
  let count = 0;

  window.setInterval(() => {
    count = (count + 1) % 200;

    const icons = line.get("icons");

    icons[0].offset = count / 2 + "%";
    line.set("icons", icons);
  }, 20);
}

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

JavaScript

// This example adds an animated symbol to a polyline.
function initMap() {
  const map = new google.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.
  const lineSymbol = {
    path: google.maps.SymbolPath.CIRCLE,
    scale: 8,
    strokeColor: "#393",
  };
  // Create the polyline and add the symbol to it via the 'icons' property.
  const line = new google.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.
function animateCircle(line) {
  let count = 0;

  window.setInterval(() => {
    count = (count + 1) % 200;

    const icons = line.get("icons");

    icons[0].offset = count / 2 + "%";
    line.set("icons", icons);
  }, 20);
}

window.initMap = initMap;
index.js

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.css

HTML

<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>
index.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-overlay-symbol-animate 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