Animate a Point Along a Route

Animate a point marker along a route using Turf.js for interpolation.

const API_KEY = 'toursprung';

    // Route: Innsbruck → Salzburg → Vienna
    const route = turf.lineString([
        [11.39085, 47.27574],
        [13.0550, 47.8095],
        [15.4395, 47.0707],
        [16.3738, 48.2082]
    ]);

    const lineLength = turf.length(route, { units: 'kilometers' });
    const steps = 500;
    const point = { type: 'Feature', geometry: { type: 'Point', coordinates: route.geometry.coordinates[0] } };

    const map = new maptoolkit.Map({
        container: 'map',
        style: `https://static.maptoolkit.net/styles/toursprung/terrain.json?api_key=${API_KEY}`,
        center: [13.5, 47.6],
        zoom: 7,
        attributionControl: { compact: false }
    });

    map.addControl(new maptoolkit.NavigationControl(), 'top-right');

    let step = 0;
    let animId;

    map.on('load', () => {
        map.addSource('route', { type: 'geojson', data: route });
        map.addSource('point', { type: 'geojson', data: point });

        map.addLayer({
            id: 'route',
            type: 'line',
            source: 'route',
            paint: { 'line-color': '#888', 'line-width': 3, 'line-dasharray': [2, 2] }
        });

        map.addLayer({
            id: 'point',
            type: 'circle',
            source: 'point',
            paint: { 'circle-radius': 10, 'circle-color': '#3887be', 'circle-stroke-width': 2, 'circle-stroke-color': '#fff' }
        });

        function animate() {
            const along = turf.along(route, (step / steps) * lineLength, { units: 'kilometers' });
            point.geometry.coordinates = along.geometry.coordinates;
            map.getSource('point').setData(point);
            if (step < steps) {
                step++;
                animId = requestAnimationFrame(animate);
            }
        }
        animate();
    });

    document.getElementById('replay').addEventListener('click', () => {
        cancelAnimationFrame(animId);
        step = 0;
        function animate() {
            const along = turf.along(route, (step / steps) * lineLength, { units: 'kilometers' });
            point.geometry.coordinates = along.geometry.coordinates;
            map.getSource('point').setData(point);
            if (step < steps) {
                step++;
                animId = requestAnimationFrame(animate);
            }
        }
        animate();
    });

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Animate a Point Along a Route – Maptoolkit Maps JS</title>
    <meta property="og:description" content="Animate a point marker along a route using Turf.js for interpolation." />
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://unpkg.com/@maptoolkit/maps@11.0.0-beta.2/dist/maptoolkit.js"></script>
    <link rel="stylesheet" href="https://unpkg.com/@maptoolkit/maps@11.0.0-beta.2/dist/maptoolkit.css" />
    <script src="https://unpkg.com/@turf/turf@6/turf.min.js"></script>
    <style>
        html, body { width: 100%; height: 100%; margin: 0; padding: 0; }
        #map { width: 100%; height: 100%; }
        #replay {
            position: absolute;
            top: 10px;
            left: 10px;
            padding: 10px 20px;
            background: #3887be;
            color: white;
            border: none;
            border-radius: 3px;
            cursor: pointer;
            font-size: 14px;
        }
    </style>
</head>
<body>
<div id="map"></div>
<button id="replay">Replay</button>
<script>
    const API_KEY = 'toursprung';

    // Route: Innsbruck → Salzburg → Vienna
    const route = turf.lineString([
        [11.39085, 47.27574],
        [13.0550, 47.8095],
        [15.4395, 47.0707],
        [16.3738, 48.2082]
    ]);

    const lineLength = turf.length(route, { units: 'kilometers' });
    const steps = 500;
    const point = { type: 'Feature', geometry: { type: 'Point', coordinates: route.geometry.coordinates[0] } };

    const map = new maptoolkit.Map({
        container: 'map',
        style: `https://static.maptoolkit.net/styles/toursprung/terrain.json?api_key=${API_KEY}`,
        center: [13.5, 47.6],
        zoom: 7,
        attributionControl: { compact: false }
    });

    map.addControl(new maptoolkit.NavigationControl(), 'top-right');

    let step = 0;
    let animId;

    map.on('load', () => {
        map.addSource('route', { type: 'geojson', data: route });
        map.addSource('point', { type: 'geojson', data: point });

        map.addLayer({
            id: 'route',
            type: 'line',
            source: 'route',
            paint: { 'line-color': '#888', 'line-width': 3, 'line-dasharray': [2, 2] }
        });

        map.addLayer({
            id: 'point',
            type: 'circle',
            source: 'point',
            paint: { 'circle-radius': 10, 'circle-color': '#3887be', 'circle-stroke-width': 2, 'circle-stroke-color': '#fff' }
        });

        function animate() {
            const along = turf.along(route, (step / steps) * lineLength, { units: 'kilometers' });
            point.geometry.coordinates = along.geometry.coordinates;
            map.getSource('point').setData(point);
            if (step < steps) {
                step++;
                animId = requestAnimationFrame(animate);
            }
        }
        animate();
    });

    document.getElementById('replay').addEventListener('click', () => {
        cancelAnimationFrame(animId);
        step = 0;
        function animate() {
            const along = turf.along(route, (step / steps) * lineLength, { units: 'kilometers' });
            point.geometry.coordinates = along.geometry.coordinates;
            map.getSource('point').setData(point);
            if (step < steps) {
                step++;
                animId = requestAnimationFrame(animate);
            }
        }
        animate();
    });
</script>
</body>
</html>

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