Cluster Marker¶
Cluster marker is a way to display a group of markers on the map.
Example¶
<!DOCTYPE html>
<html lang="en">
<head>
<title>Create and style clusters</title>
<meta property="og:description" content="Use MapLibre GL JS' built-in functions to visualize points as clusters." />
<meta charset='utf-8'>
<meta name="viewport" content="width=device-width, initial-scale=1">
<script src='https://unpkg.com/@vietmap/vietmap-gl-js@4.2.0/vietmap-gl.js'></script>
<link rel='stylesheet' href='https://unpkg.com/@vietmap/vietmap-gl-js@4.2.0/vietmap-gl.css' />
<style>
body { margin: 0; padding: 0; }
html, body, #map { height: 100%; }
</style>
</head>
<body>
<div id="map"></div>
<script>
const map = new vietmapgl.Map({
container: 'map',
style: 'https://maps.vietmap.vn/mt/tm/style.json?apikey=YOUR_API_KEY_HERE',
center: [106.59179687498357, 10.66995747013945],
zoom: 3
});
map.on('load', () => {
// Add a new source from our GeoJSON data and
// set the 'cluster' option to true. GL-JS will
// add the point_count property to your source data.
map.addSource('earthquakes', {
type: 'geojson',
// Point to GeoJSON data. This example visualizes all M1.0+ earthquakes
// from 12/22/15 to 1/21/16 as logged by USGS' Earthquake hazards program.
data: 'https://maplibre.org/maplibre-gl-js/docs/assets/earthquakes.geojson',
cluster: true,
clusterMaxZoom: 14, // Max zoom to cluster points on
clusterRadius: 50 // Radius of each cluster when clustering points (defaults to 50)
});
map.addLayer({
id: 'clusters',
type: 'circle',
source: 'earthquakes',
filter: ['has', 'point_count'],
paint: {
// Use step expressions (https://maplibre.org/maplibre-style-spec/#expressions-step)
// with three steps to implement three types of circles:
// * Blue, 20px circles when point count is less than 100
// * Yellow, 30px circles when point count is between 100 and 750
// * Pink, 40px circles when point count is greater than or equal to 750
'circle-color': [
'step',
['get', 'point_count'],
'#51bbd6',
100,
'#f1f075',
750,
'#f28cb1'
],
'circle-radius': [
'step',
['get', 'point_count'],
20,
100,
30,
750,
40
]
}
});
map.addLayer({
id: 'cluster-count',
type: 'symbol',
source: 'earthquakes',
filter: ['has', 'point_count'],
layout: {
'text-field': '{point_count_abbreviated}',
'text-size': 12
}
});
map.addLayer({
id: 'unclustered-point',
type: 'circle',
source: 'earthquakes',
filter: ['!', ['has', 'point_count']],
paint: {
'circle-color': '#11b4da',
'circle-radius': 4,
'circle-stroke-width': 1,
'circle-stroke-color': '#fff'
}
});
// inspect a cluster on click
map.on('click', 'clusters', async (e) => {
const features = map.queryRenderedFeatures(e.point, {
layers: ['clusters']
});
const clusterId = features[0].properties.cluster_id;
const zoom = await map.getSource('earthquakes').getClusterExpansionZoom(clusterId);
map.easeTo({
center: features[0].geometry.coordinates,
zoom
});
});
// When a click event occurs on a feature in
// the unclustered-point layer, open a popup at
// the location of the feature, with
// description HTML from its properties.
map.on('click', 'unclustered-point', (e) => {
const coordinates = e.features[0].geometry.coordinates.slice();
const mag = e.features[0].properties.mag;
let tsunami;
if (e.features[0].properties.tsunami === 1) {
tsunami = 'yes';
} else {
tsunami = 'no';
}
// Ensure that if the map is zoomed out such that
// multiple copies of the feature are visible, the
// popup appears over the copy being pointed to.
while (Math.abs(e.lngLat.lng - coordinates[0]) > 180) {
coordinates[0] += e.lngLat.lng > coordinates[0] ? 360 : -360;
}
new vietmapgl.Popup()
.setLngLat(coordinates)
.setHTML(
`magnitude: ${mag}<br>Was there a tsunami?: ${tsunami}`
)
.addTo(map);
});
map.on('mouseenter', 'clusters', () => {
map.getCanvas().style.cursor = 'pointer';
});
map.on('mouseleave', 'clusters', () => {
map.getCanvas().style.cursor = '';
});
});
</script>
</body>
</html>
