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/maplibre-gl@4.7.1/dist/maplibre-gl.css' />
<script src='https://unpkg.com/maplibre-gl@4.7.1/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>