Animate a line
This example animates a line by updating a GeoJSON source on each frame.
It uses addSource to add a GeoJSON source and uses addLayer to add a line layer to the map.
When the animation begins, the data in the GeoJSON object changes, and the line appears animated on the map.
The example Update a feature in realtime uses a similar approach to create an animation.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Animate a line</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no">
<link href="https://api.mapbox.com/mapbox-gl-js/v3.9.0/mapbox-gl.css" rel="stylesheet">
<script src="https://api.mapbox.com/mapbox-gl-js/v3.9.0/mapbox-gl.js"></script>
<style>
body { margin: 0; padding: 0; }
#map { position: absolute; top: 0; bottom: 0; width: 100%; }
</style>
</head>
<body>
<style>
button {
position: absolute;
margin: 20px;
}
#pause::after {
content: 'Pause';
}
#pause.pause::after {
content: 'Play';
}
</style>
<div id="map"></div>
<button id="pause"></button>
<script>
// TO MAKE THE MAP APPEAR YOU MUST
// ADD YOUR ACCESS TOKEN FROM
// https://account.mapbox.com
mapboxgl.accessToken = 'YOUR_MAPBOX_ACCESS_TOKEN';
const map = new mapboxgl.Map({
container: 'map',
// Choose from Mapbox's core styles, or make your own style with Mapbox Studio
style: 'mapbox://styles/mapbox/streets-v12',
center: [0, 0],
zoom: 0.5,
projection: 'equalEarth'
});
// Create a GeoJSON source with an empty lineString.
const geojson = {
'type': 'FeatureCollection',
'features': [
{
'type': 'Feature',
'geometry': {
'type': 'LineString',
'coordinates': [[0, 0]]
}
}
]
};
const speedFactor = 30; // number of frames per longitude degree
let animation; // to store and cancel the animation
let startTime = 0;
let progress = 0; // progress = timestamp - startTime
let resetTime = false; // indicator of whether time reset is needed for the animation
const pauseButton = document.getElementById('pause');
map.on('load', () => {
map.addSource('line', {
'type': 'geojson',
'data': geojson
});
// add the line which will be modified in the animation
map.addLayer({
'id': 'line-animation',
'type': 'line',
'source': 'line',
'layout': {
'line-cap': 'round',
'line-join': 'round'
},
'paint': {
'line-color': '#ed6498',
'line-width': 5,
'line-opacity': 0.8
}
});
startTime = performance.now();
animateLine();
// click the button to pause or play
pauseButton.addEventListener('click', () => {
pauseButton.classList.toggle('pause');
if (pauseButton.classList.contains('pause')) {
cancelAnimationFrame(animation);
} else {
resetTime = true;
animateLine();
}
});
// reset startTime and progress once the tab loses or gains focus
// requestAnimationFrame also pauses on hidden tabs by default
document.addEventListener('visibilitychange', () => {
resetTime = true;
});
// animated in a circle as a sine wave along the map.
function animateLine(timestamp) {
if (resetTime) {
// resume previous progress
startTime = performance.now() - progress;
resetTime = false;
} else {
progress = timestamp - startTime;
}
// restart if it finishes a loop
if (progress > speedFactor * 360) {
startTime = timestamp;
geojson.features[0].geometry.coordinates = [];
} else {
const x = progress / speedFactor;
// draw a sine wave with some math.
const y = Math.sin((x * Math.PI) / 90) * 40;
// append new coordinates to the lineString
geojson.features[0].geometry.coordinates.push([x, y]);
// then update the map
map.getSource('line').setData(geojson);
}
// Request the next frame of the animation.
animation = requestAnimationFrame(animateLine);
}
});
</script>
</body>
</html>
This code snippet will not work as expected until you replace
YOUR_MAPBOX_ACCESS_TOKEN with an access token from your Mapbox account.import React, { useEffect, useState, useRef } from 'react';
import mapboxgl from 'mapbox-gl';
import 'mapbox-gl/dist/mapbox-gl.css';
const MapboxExample = () => {
const [playback, setPlayback] = useState('Pause');
const mapContainerRef = useRef();
const mapRef = useRef(null);
const animationRef = useRef(null);
const resetTimeRef = useRef(false);
const startTimeRef = useRef(0);
const progressRef = useRef(0);
const geojsonRef = useRef({
type: 'FeatureCollection',
features: [
{
type: 'Feature',
geometry: {
type: 'LineString',
coordinates: [[0, 0]]
}
}
]
});
const speedFactor = 30;
const animateLine = (timestamp) => {
if (resetTimeRef.current) {
startTimeRef.current = performance.now() - progressRef.current;
resetTimeRef.current = false;
} else {
progressRef.current = timestamp - startTimeRef.current;
}
if (progressRef.current > speedFactor * 360) {
startTimeRef.current = timestamp;
geojsonRef.current.features[0].geometry.coordinates = [];
} else {
const x = progressRef.current / speedFactor;
const y = Math.sin((x * Math.PI) / 90) * 40;
geojsonRef.current.features[0].geometry.coordinates.push([x, y]);
mapRef.current.getSource('line').setData(geojsonRef.current);
}
animationRef.current = requestAnimationFrame(animateLine);
};
const handleClick = () => {
if (playback === 'Pause') {
cancelAnimationFrame(animationRef.current);
setPlayback('Play');
} else {
resetTimeRef.current = true;
animateLine();
setPlayback('Pause');
}
};
useEffect(() => {
// TO MAKE THE MAP APPEAR YOU MUST
// ADD YOUR ACCESS TOKEN FROM
// https://account.mapbox.com
mapboxgl.accessToken = 'YOUR_MAPBOX_ACCESS_TOKEN';
mapRef.current = new mapboxgl.Map({
container: 'map',
style: 'mapbox://styles/mapbox/streets-v12',
center: [0, 0],
zoom: 0.5,
projection: 'equalEarth'
});
mapRef.current.on('load', () => {
mapRef.current.addSource('line', {
type: 'geojson',
data: {
type: 'FeatureCollection',
features: [
{
type: 'Feature',
geometry: {
type: 'LineString',
coordinates: [[0, 0]]
}
}
]
}
});
mapRef.current.addLayer({
id: 'line-animation',
type: 'line',
source: 'line',
layout: {
'line-cap': 'round',
'line-join': 'round'
},
paint: {
'line-color': '#ed6498',
'line-width': 5,
'line-opacity': 0.8
}
});
startTimeRef.current = performance.now();
animateLine();
document.addEventListener('visibilitychange', () => {
resetTimeRef.current = true;
});
});
return () => {
if (animationRef.current) {
cancelAnimationFrame(animationRef.current);
}
};
}, []);
return (
<div style={{ height: '100%', position: 'relative' }}>
<div id="map" ref={mapContainerRef} style={{ height: '100%' }}></div>
<button
id="pause"
onClick={handleClick}
style={{
position: 'absolute',
margin: '20px',
top: '20px',
backgroundColor: 'lightgrey',
border: '1px solid gray',
borderRadius: '3px',
padding: '5px 10px'
}}
>
{playback}
</button>
</div>
);
};
export default MapboxExample;
This code snippet will not work as expected until you replace
YOUR_MAPBOX_ACCESS_TOKEN with an access token from your Mapbox account.Was this example helpful?