Complex Polylines

Click two or more points on the map to draw polylines.

Read the documentation.

TypeScript

// This example creates an interactive map which constructs a polyline based on
// user clicks. Note that the polyline only appears once its path property
// contains two LatLng coordinates.

let poly: google.maps.Polyline;
let map: google.maps.Map;

function initMap(): void {
  map = new google.maps.Map(document.getElementById("map") as HTMLElement, {
    zoom: 7,
    center: { lat: 41.879, lng: -87.624 }, // Center the map on Chicago, USA.
  });

  poly = new google.maps.Polyline({
    strokeColor: "#000000",
    strokeOpacity: 1.0,
    strokeWeight: 3,
  });
  poly.setMap(map);

  // Add a listener for the click event
  map.addListener("click", addLatLng);
}

// Handles click events on a map, and adds a new point to the Polyline.
function addLatLng(event: google.maps.MapMouseEvent) {
  const path = poly.getPath();

  // Because path is an MVCArray, we can simply append a new coordinate
  // and it will automatically appear.
  path.push(event.latLng);

  // Add a new marker at the new plotted point on the polyline.
  new google.maps.Marker({
    position: event.latLng,
    title: "#" + path.getLength(),
    map: map,
  });
}

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

JavaScript

// This example creates an interactive map which constructs a polyline based on
// user clicks. Note that the polyline only appears once its path property
// contains two LatLng coordinates.
let poly;
let map;

function initMap() {
  map = new google.maps.Map(document.getElementById("map"), {
    zoom: 7,
    center: { lat: 41.879, lng: -87.624 }, // Center the map on Chicago, USA.
  });
  poly = new google.maps.Polyline({
    strokeColor: "#000000",
    strokeOpacity: 1.0,
    strokeWeight: 3,
  });
  poly.setMap(map);
  // Add a listener for the click event
  map.addListener("click", addLatLng);
}

// Handles click events on a map, and adds a new point to the Polyline.
function addLatLng(event) {
  const path = poly.getPath();

  // Because path is an MVCArray, we can simply append a new coordinate
  // and it will automatically appear.
  path.push(event.latLng);
  // Add a new marker at the new plotted point on the polyline.
  new google.maps.Marker({
    position: event.latLng,
    title: "#" + path.getLength(),
    map: map,
  });
}

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>Complex Polylines</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>

    <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 callback 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
     with https://www.npmjs.com/package/@googlemaps/js-api-loader.
    -->
    <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-polyline-complex 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