Removing Polylines

  • This example demonstrates how to add and remove a polyline from a Google Map using JavaScript/TypeScript.

  • It provides UI controls (buttons) to trigger the addition and removal of the polyline.

  • The polyline is initialized with a predefined path and styling.

  • Users can interact with the controls to dynamically show or hide the polyline on the map.

  • The sample code includes HTML, CSS, and JavaScript/TypeScript components for implementation.

This example adds a UI control that allows the user to remove the polyline from the map.

Read the documentation.

TypeScript

// This example adds a UI control allowing users to remove the polyline
// from the map.

let flightPath: google.maps.Polyline;
const mapElement = document.querySelector('gmp-map')!;
let innerMap: google.maps.Map;

async function init() {
    const { Polyline } = await google.maps.importLibrary('maps');
    innerMap = mapElement.innerMap;

    const flightPathCoordinates: google.maps.LatLngLiteral[] = [
        { lat: 37.772, lng: -122.214 },
        { lat: 21.291, lng: -157.821 },
        { lat: -18.142, lng: 178.431 },
        { lat: -27.467, lng: 153.027 },
    ];

    flightPath = new Polyline({
        path: flightPathCoordinates,
        strokeColor: '#FF0000',
        strokeOpacity: 1.0,
        strokeWeight: 2,
    });

    // add event listener for click event
    document.getElementById('add-line')!.addEventListener('click', addLine);
    document
        .getElementById('remove-line')!
        .addEventListener('click', removeLine);

    // initialize with line
    addLine();
}

function addLine(): void {
    flightPath.setMap(innerMap);
}

function removeLine(): void {
    flightPath.setMap(null);
}

void init();

JavaScript

// This example adds a UI control allowing users to remove the polyline
// from the map.

let flightPath;
const mapElement = document.querySelector('gmp-map');
let innerMap;

async function init() {
    const { Polyline } = await google.maps.importLibrary('maps');
    innerMap = mapElement.innerMap;

    const flightPathCoordinates = [
        { lat: 37.772, lng: -122.214 },
        { lat: 21.291, lng: -157.821 },
        { lat: -18.142, lng: 178.431 },
        { lat: -27.467, lng: 153.027 },
    ];

    flightPath = new Polyline({
        path: flightPathCoordinates,
        strokeColor: '#FF0000',
        strokeOpacity: 1.0,
        strokeWeight: 2,
    });

    // add event listener for click event
    document.getElementById('add-line').addEventListener('click', addLine);
    document
        .getElementById('remove-line')
        .addEventListener('click', removeLine);

    // initialize with line
    addLine();
}

function addLine() {
    flightPath.setMap(innerMap);
}

function removeLine() {
    flightPath.setMap(null);
}

void init();

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;
}

#floating-panel {
    position: absolute;
    top: 10px;
    left: 25%;
    z-index: 5;
    background-color: #fff;
    padding: 5px;
    border: 1px solid #999;
    text-align: center;
    font-family: 'Roboto', sans-serif;
    line-height: 30px;
    padding-left: 10px;
}

HTML

<html>
    <head>
        <title>Removing Polylines</title>

        <link rel="stylesheet" type="text/css" href="./style.css" />
        <script type="module" src="./index.js"></script>
        <script>
            // prettier-ignore
            (g=>{var h,a,k,p="The Google Maps JavaScript API",c="google",l="importLibrary",q="__ib__",m=document,b=window;b=b[c]||(b[c]={});var d=b.maps||(b.maps={}),r=new Set,e=new URLSearchParams,u=()=>h||(h=new Promise(async(f,n)=>{await (a=m.createElement("script"));e.set("libraries",[...r]+"");for(k in g)e.set(k.replace(/[A-Z]/g,t=>"_"+t[0].toLowerCase()),g[k]);e.set("callback",c+".maps."+q);a.src=`https://maps.${c}apis.com/maps/api/js?`+e;d[q]=f;a.onerror=()=>h=n(Error(p+" could not load."));a.nonce=m.querySelector("script[nonce]")?.nonce||"";m.head.append(a)}));d[l]?console.warn(p+" only loads once. Ignoring:",g):d[l]=(f,...n)=>r.add(f)&&u().then(()=>d[l](f,...n))})({
                key: "GOOGLE_MAPS_API_KEY"
            });
        </script>
    </head>
    <body>
        <gmp-map center="0, -180" zoom="3">
            <div id="floating-panel" slot="control-block-start-inline-center">
                <input id="remove-line" type="button" value="Remove line" />
                <input id="add-line" type="button" value="Restore line" />
            </div>
        </gmp-map>
    </body>
</html>

Clone Sample

Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. You will also need a Google Maps API key.

The following commands clone the repository, install dependencies, and copy the environment file. 

  git clone https://github.com/googlemaps-samples/js-api-samples.git
  cd js-api-samples
  npm i
  cp .env.template .env

Once you copy the environment file, make sure to open the .env file and replace <Insert your own development API key here> with your actual API key before starting the sample. 

  cd samples/polyline-remove
  npm start