This example demonstrates computing the heading between two coordinates using the Geometry library. Drag the markers on the map to see the origin, destination and heading change accordingly.
Read the documentation.
TypeScript
// This example requires the Geometry library. Include the libraries=geometry
// parameter when you first load the API. For example:
// <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=geometry">
let marker1: google.maps.Marker, marker2: google.maps.Marker;
let poly: google.maps.Polyline, geodesicPoly: google.maps.Polyline;
function initMap(): void {
const map = new google.maps.Map(
document.getElementById("map") as HTMLElement,
{
zoom: 4,
center: { lat: 34, lng: -40.605 },
}
);
map.controls[google.maps.ControlPosition.TOP_CENTER].push(
document.getElementById("info") as HTMLElement
);
marker1 = new google.maps.Marker({
map,
draggable: true,
position: { lat: 40.714, lng: -74.006 },
});
marker2 = new google.maps.Marker({
map,
draggable: true,
position: { lat: 48.857, lng: 2.352 },
});
const bounds = new google.maps.LatLngBounds(
marker1.getPosition() as google.maps.LatLng,
marker2.getPosition() as google.maps.LatLng
);
map.fitBounds(bounds);
google.maps.event.addListener(marker1, "position_changed", update);
google.maps.event.addListener(marker2, "position_changed", update);
poly = new google.maps.Polyline({
strokeColor: "#FF0000",
strokeOpacity: 1.0,
strokeWeight: 3,
map: map,
});
geodesicPoly = new google.maps.Polyline({
strokeColor: "#CC0099",
strokeOpacity: 1.0,
strokeWeight: 3,
geodesic: true,
map: map,
});
update();
}
function update() {
const path = [
marker1.getPosition() as google.maps.LatLng,
marker2.getPosition() as google.maps.LatLng,
];
poly.setPath(path);
geodesicPoly.setPath(path);
const heading = google.maps.geometry.spherical.computeHeading(
path[0],
path[1]
);
(document.getElementById("heading") as HTMLInputElement).value =
String(heading);
(document.getElementById("origin") as HTMLInputElement).value = String(
path[0]
);
(document.getElementById("destination") as HTMLInputElement).value = String(
path[1]
);
}
declare global {
interface Window {
initMap: () => void;
}
}
window.initMap = initMap;
JavaScript
// This example requires the Geometry library. Include the libraries=geometry
// parameter when you first load the API. For example:
// <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=geometry">
let marker1, marker2;
let poly, geodesicPoly;
function initMap() {
const map = new google.maps.Map(document.getElementById("map"), {
zoom: 4,
center: { lat: 34, lng: -40.605 },
});
map.controls[google.maps.ControlPosition.TOP_CENTER].push(
document.getElementById("info"),
);
marker1 = new google.maps.Marker({
map,
draggable: true,
position: { lat: 40.714, lng: -74.006 },
});
marker2 = new google.maps.Marker({
map,
draggable: true,
position: { lat: 48.857, lng: 2.352 },
});
const bounds = new google.maps.LatLngBounds(
marker1.getPosition(),
marker2.getPosition(),
);
map.fitBounds(bounds);
google.maps.event.addListener(marker1, "position_changed", update);
google.maps.event.addListener(marker2, "position_changed", update);
poly = new google.maps.Polyline({
strokeColor: "#FF0000",
strokeOpacity: 1.0,
strokeWeight: 3,
map: map,
});
geodesicPoly = new google.maps.Polyline({
strokeColor: "#CC0099",
strokeOpacity: 1.0,
strokeWeight: 3,
geodesic: true,
map: map,
});
update();
}
function update() {
const path = [marker1.getPosition(), marker2.getPosition()];
poly.setPath(path);
geodesicPoly.setPath(path);
const heading = google.maps.geometry.spherical.computeHeading(
path[0],
path[1],
);
document.getElementById("heading").value = String(heading);
document.getElementById("origin").value = String(path[0]);
document.getElementById("destination").value = String(path[1]);
}
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;
}
#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>Navigation Functions (Heading)</title>
<link rel="stylesheet" type="text/css" href="./style.css" />
<script type="module" src="./index.js"></script>
</head>
<body>
<div id="map"></div>
<div id="floating-panel">
Origin: <input type="text" readonly id="origin" /> Destination:
<input type="text" readonly id="destination" /><br />
Heading: <input type="text" readonly id="heading" /> degrees
</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&libraries=geometry&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-geometry-headings https://github.com/googlemaps/js-samples.gitcd js-samplesnpm inpm start
Other samples can be tried by switching to any branch beginning with sample-SAMPLE_NAME.
git checkout sample-SAMPLE_NAMEnpm inpm start