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Create a draggable point

Drag the point to a new location on a map and populate its coordinates in a display.

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Create a draggable point</title>
    <meta property="og:description" content="Drag the point to a new location on a map and populate its coordinates in a display." />
    <meta charset='utf-8'>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel='stylesheet' href='https://unpkg.com/[email protected]/dist/maplibre-gl.css' />
    <script src='https://unpkg.com/[email protected]/dist/maplibre-gl.js'></script>
    <style>
        body { margin: 0; padding: 0; }
        html, body, #map { height: 100%; }
    </style>
</head>
<body>
<style>
    .coordinates {
        background: rgba(0, 0, 0, 0.5);
        color: #fff;
        position: absolute;
        bottom: 40px;
        left: 10px;
        padding: 5px 10px;
        margin: 0;
        font-size: 11px;
        line-height: 18px;
        border-radius: 3px;
        display: none;
    }
</style>

<div id="map"></div>
<pre id="coordinates" class="coordinates"></pre>

<script>
    const coordinates = document.getElementById('coordinates');
    const map = new maplibregl.Map({
        container: 'map',
        style:
            'https://api.maptiler.com/maps/streets/style.json?key=get_your_own_OpIi9ZULNHzrESv6T2vL',
        center: [0, 0],
        zoom: 2
    });

    const canvas = map.getCanvasContainer();

    const geojson = {
        'type': 'FeatureCollection',
        'features': [
            {
                'type': 'Feature',
                'geometry': {
                    'type': 'Point',
                    'coordinates': [0, 0]
                }
            }
        ]
    };

    function onMove(e) {
        const coords = e.lngLat;

        // Set a UI indicator for dragging.
        canvas.style.cursor = 'grabbing';

        // Update the Point feature in `geojson` coordinates
        // and call setData to the source layer `point` on it.
        geojson.features[0].geometry.coordinates = [coords.lng, coords.lat];
        map.getSource('point').setData(geojson);
    }

    function onUp(e) {
        const coords = e.lngLat;

        // Print the coordinates of where the point had
        // finished being dragged to on the map.
        coordinates.style.display = 'block';
        coordinates.innerHTML =
            `Longitude: ${coords.lng}<br />Latitude: ${coords.lat}`;
        canvas.style.cursor = '';

        // Unbind mouse/touch events
        map.off('mousemove', onMove);
        map.off('touchmove', onMove);
    }

    map.on('load', () => {
        // Add a single point to the map
        map.addSource('point', {
            'type': 'geojson',
            'data': geojson
        });

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

        // When the cursor enters a feature in the point layer, prepare for dragging.
        map.on('mouseenter', 'point', () => {
            map.setPaintProperty('point', 'circle-color', '#3bb2d0');
            canvas.style.cursor = 'move';
        });

        map.on('mouseleave', 'point', () => {
            map.setPaintProperty('point', 'circle-color', '#3887be');
            canvas.style.cursor = '';
        });

        map.on('mousedown', 'point', (e) => {
            // Prevent the default map drag behavior.
            e.preventDefault();

            canvas.style.cursor = 'grab';

            map.on('mousemove', onMove);
            map.once('mouseup', onUp);
        });

        map.on('touchstart', 'point', (e) => {
            if (e.points.length !== 1) return;

            // Prevent the default map drag behavior.
            e.preventDefault();

            map.on('touchmove', onMove);
            map.once('touchend', onUp);
        });
    });
</script>
</body>
</html>