Animate a point along a line | NMaps GL JS Docs

This example animates the position of a point by updating a GeoJSON source on each frame.

It first defines the animation as a GeoJSON object. Then it adds a GeoJSON source referring to that GeoJSON, and adds a circle layer that uses that source.

Finally, it starts the animation with the JavaScript window.requestAnimationFrame() method to continuously update the GeoJSON object, resulting in a moving circle on the map.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Animate a point along a line</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<script src="https://cdn.ndrive.com/nmapsgl/v.1.6.8/nmaps-gl.js"></script>
<link href="https://cdn.ndrive.com/nmapsgl/v.1.6.8/nmaps-gl.css" rel="stylesheet" />
<style>
	body { margin: 0; padding: 0; }
	#map { position: absolute; top: 0; bottom: 0; width: 100%; }
</style>
</head>
<body>
<div id="map"></div>
<script>
	// TO MAKE THE MAP APPEAR YOU MUST ADD YOUR ACCESS TOKEN
	nmapsgl.accessToken = '<your access token here>';
	
const map = new nmapsgl.Map({
container: 'map',
style: 'Streets',
center: [0, 0],
zoom: 2
});
 
const radius = 20;
 
function pointOnCircle(angle) {
return {
'type': 'Point',
'coordinates': [Math.cos(angle) * radius, Math.sin(angle) * radius]
};
}
 
map.on('load', () => {
// Add a source and layer displaying a point which will be animated in a circle.
map.addSource('point', {
'type': 'geojson',
'data': pointOnCircle(0)
});
 
map.addLayer({
'id': 'point',
'source': 'point',
'type': 'circle',
'paint': {
'circle-radius': 10,
'circle-color': '#007cbf'
}
});
 
function animateMarker(timestamp) {
// Update the data to a new position based on the animation timestamp. The
// divisor in the expression `timestamp / 1000` controls the animation speed.
map.getSource('point').setData(pointOnCircle(timestamp / 1000));
 
// Request the next frame of the animation.
requestAnimationFrame(animateMarker);
}
 
// Start the animation.
animateMarker(0);
});
</script>
 
</body>
</html>