Map Clustering with GeoJSON
This sample illustrates the usage of map clustering with GeoJSON data.
Example
Map Clustering with GeoJSON
import type * as GeoJSON from "geojson";
import Supercluster from "supercluster";
let map: woosmap.map.Map;
let infoWindow: woosmap.map.InfoWindow;
let index: Supercluster;
let markers: woosmap.map.Marker[] = [];
const GEOJSON_URL = "https://demo.woosmap.com/misc/data/uk-all-pubs.geojson";
const ICON_URL = "https://images.woosmap.com/dot-green.svg"; //
const SUPERCLUSTER_OPTIONS: Supercluster.Options<any, any> = {
radius: 40,
extent: 256,
maxZoom: 14,
minPoints: 5,
};
function initMap(): void {
infoWindow = new woosmap.map.InfoWindow({});
map = new window.woosmap.map.Map(
document.getElementById("map") as HTMLElement,
{
center: {
lat: 55.5,
lng: -4,
},
zoom: 5.7,
styles: [
{
elementType: "geometry",
stylers: [{ color: "#f6f6f6" }],
},
{
elementType: "labels.icon",
stylers: [{ visibility: "off" }],
},
{
elementType: "labels.text.fill",
stylers: [{ color: "#616161" }],
},
{
elementType: "labels.text.stroke",
stylers: [{ color: "#f5f5f5" }],
},
{
featureType: "administrative.land_parcel",
elementType: "labels.text.fill",
stylers: [{ color: "#bdbdbd" }],
},
{
featureType: "road",
elementType: "geometry",
stylers: [{ color: "#ffffff" }],
},
{
featureType: "road.arterial",
elementType: "labels.text.fill",
stylers: [{ color: "#757575" }],
},
{
featureType: "road.highway",
elementType: "geometry",
stylers: [{ color: "#dadada" }],
},
{
featureType: "road.highway",
elementType: "labels.text.fill",
stylers: [{ color: "#616161" }],
},
{
featureType: "road.local",
elementType: "labels.text.fill",
stylers: [{ color: "#9e9e9e" }],
},
{
featureType: "transit.line",
elementType: "geometry",
stylers: [{ color: "#e5e5e5" }],
},
{
featureType: "transit.station",
elementType: "geometry",
stylers: [{ color: "#eeeeee" }],
},
{
featureType: "water",
elementType: "geometry",
stylers: [{ color: "#c9c9c9" }],
},
{
featureType: "water",
elementType: "labels.text.fill",
stylers: [{ color: "#9e9e9e" }],
},
],
},
);
fetchGeoJsonData(GEOJSON_URL).then((data) => {
const geojsonFeatures = data["features"];
index = new Supercluster(SUPERCLUSTER_OPTIONS).load(geojsonFeatures);
update();
});
manageEvents();
}
function fetchGeoJsonData(url: string): Promise<GeoJSON.Point[]> {
return fetch(url).then((response) => response.json());
}
function manageEvents(): void {
map.addListener("dragend", debounce(update, 20));
map.addListener("zoom_changed", debounce(update, 20));
window.addEventListener("resize", debounce(update, 100));
}
function update(): void {
clearMarkers();
const bounds = map.getBounds();
const bbox: GeoJSON.BBox = [
bounds.getSouthWest().lng(),
bounds.getSouthWest().lat(),
bounds.getNorthEast().lng(),
bounds.getNorthEast().lat(),
];
const clusterData = index.getClusters(bbox, map.getZoom());
for (const feature of clusterData) {
const latlng = {
lat: feature.geometry.coordinates[1],
lng: feature.geometry.coordinates[0],
};
markers.push(createClusterIcon(feature, latlng));
}
}
function clearMarkers(): void {
for (const marker of markers) {
marker.setMap(null);
}
markers = [];
}
function createClusterIcon(
feature: any,
latlng: woosmap.map.LatLngLiteral,
): woosmap.map.Marker {
if (!feature.properties.cluster) {
return createMarker(feature, latlng);
}
return createCluster(feature, latlng);
}
function createCluster(
feature: any,
latlng: woosmap.map.LatLngLiteral,
): woosmap.map.Marker {
const count = feature.properties.point_count;
const color = count < 80 ? "#0B9D58" : count < 500 ? "#F5B300" : "#DA0A40";
const size = count < 80 ? 45 : count < 400 ? 55 : 65;
const svg = window.btoa(`
<svg fill="${color}" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 240 240">
<circle cx="120" cy="120" opacity=".8" r="70" />
<circle cx="120" cy="120" opacity=".3" r="80" />
<circle cx="120" cy="120" opacity=".2" r="110" />
</svg>`);
const marker = new window.woosmap.map.Marker({
label: {
text: feature.properties["point_count_abbreviated"],
color: "white",
},
position: latlng,
icon: {
url: `data:image/svg+xml;base64,${svg}`,
scaledSize: new window.woosmap.map.Size(size, size),
},
map: map,
});
marker.addListener("click", (e) => {
infoWindow.close();
const expansionZoom = index.getClusterExpansionZoom(
feature.properties["cluster_id"],
);
map.setCenter(marker.getPosition());
map.setZoom(expansionZoom);
});
return marker;
}
function createMarker(
feature: any,
latlng: woosmap.map.LatLngLiteral,
): woosmap.map.Marker {
const marker = new window.woosmap.map.Marker({
icon: {
url: ICON_URL,
scaledSize: {
height: 20,
width: 20,
},
},
position: latlng,
map: map,
});
marker.addListener("click", () => {
infoWindow.setContent(`<h3>${feature.properties.name}</h3>`);
infoWindow.open(map, marker);
});
return marker;
}
function debounce<T extends (...args: any[]) => ReturnType<T>>(
callback: T,
timeout: number,
): (...args: Parameters<T>) => void {
let timer: ReturnType<typeof setTimeout>;
return (...args: Parameters<T>) => {
clearTimeout(timer);
timer = setTimeout(() => {
callback(...args);
}, timeout);
};
}
declare global {
interface Window {
initMap: () => void;
}
}
window.initMap = initMap;
const GEOJSON_URL = "https://demo.woosmap.com/misc/data/uk-all-pubs.geojson";
const ICON_URL = "https://images.woosmap.com/dot-green.svg"; //
const SUPERCLUSTER_OPTIONS = {
radius: 40,
extent: 256,
maxZoom: 14,
minPoints: 5,
};
function initMap() {
infoWindow = new woosmap.map.InfoWindow({});
map = new window.woosmap.map.Map(document.getElementById("map"), {
center: {
lat: 55.5,
lng: -4,
},
zoom: 5.7,
styles: [
{
elementType: "geometry",
stylers: [{ color: "#f6f6f6" }],
},
{
elementType: "labels.icon",
stylers: [{ visibility: "off" }],
},
{
elementType: "labels.text.fill",
stylers: [{ color: "#616161" }],
},
{
elementType: "labels.text.stroke",
stylers: [{ color: "#f5f5f5" }],
},
{
featureType: "administrative.land_parcel",
elementType: "labels.text.fill",
stylers: [{ color: "#bdbdbd" }],
},
{
featureType: "road",
elementType: "geometry",
stylers: [{ color: "#ffffff" }],
},
{
featureType: "road.arterial",
elementType: "labels.text.fill",
stylers: [{ color: "#757575" }],
},
{
featureType: "road.highway",
elementType: "geometry",
stylers: [{ color: "#dadada" }],
},
{
featureType: "road.highway",
elementType: "labels.text.fill",
stylers: [{ color: "#616161" }],
},
{
featureType: "road.local",
elementType: "labels.text.fill",
stylers: [{ color: "#9e9e9e" }],
},
{
featureType: "transit.line",
elementType: "geometry",
stylers: [{ color: "#e5e5e5" }],
},
{
featureType: "transit.station",
elementType: "geometry",
stylers: [{ color: "#eeeeee" }],
},
{
featureType: "water",
elementType: "geometry",
stylers: [{ color: "#c9c9c9" }],
},
{
featureType: "water",
elementType: "labels.text.fill",
stylers: [{ color: "#9e9e9e" }],
},
],
});
fetchGeoJsonData(GEOJSON_URL).then((data) => {
const geojsonFeatures = data["features"];
index = new Supercluster(SUPERCLUSTER_OPTIONS).load(geojsonFeatures);
update();
});
manageEvents();
}
function fetchGeoJsonData(url) {
return fetch(url).then((response) => response.json());
}
function manageEvents() {
map.addListener("dragend", debounce(update, 20));
map.addListener("zoom_changed", debounce(update, 20));
window.addEventListener("resize", debounce(update, 100));
}
function update() {
clearMarkers();
const bounds = map.getBounds();
const bbox = [
bounds.getSouthWest().lng(),
bounds.getSouthWest().lat(),
bounds.getNorthEast().lng(),
bounds.getNorthEast().lat(),
];
const clusterData = index.getClusters(bbox, map.getZoom());
for (const feature of clusterData) {
const latlng = {
lat: feature.geometry.coordinates[1],
lng: feature.geometry.coordinates[0],
};
markers.push(createClusterIcon(feature, latlng));
}
}
function clearMarkers() {
for (const marker of markers) {
marker.setMap(null);
}
markers = [];
}
function createClusterIcon(feature, latlng) {
if (!feature.properties.cluster) {
return createMarker(feature, latlng);
}
return createCluster(feature, latlng);
}
function createCluster(feature, latlng) {
const count = feature.properties.point_count;
const color = count < 80 ? "#0B9D58" : count < 500 ? "#F5B300" : "#DA0A40";
const size = count < 80 ? 45 : count < 400 ? 55 : 65;
const svg = window.btoa(`
<svg fill="${color}" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 240 240">
<circle cx="120" cy="120" opacity=".8" r="70" />
<circle cx="120" cy="120" opacity=".3" r="80" />
<circle cx="120" cy="120" opacity=".2" r="110" />
</svg>`);
const marker = new window.woosmap.map.Marker({
label: {
text: feature.properties["point_count_abbreviated"],
color: "white",
},
position: latlng,
icon: {
url: `data:image/svg+xml;base64,${svg}`,
scaledSize: new window.woosmap.map.Size(size, size),
},
map: map,
});
marker.addListener("click", (e) => {
infoWindow.close();
const expansionZoom = index.getClusterExpansionZoom(
feature.properties["cluster_id"],
);
map.setCenter(marker.getPosition());
map.setZoom(expansionZoom);
});
return marker;
}
function createMarker(feature, latlng) {
const marker = new window.woosmap.map.Marker({
icon: {
url: ICON_URL,
scaledSize: {
height: 20,
width: 20,
},
},
position: latlng,
map: map,
});
marker.addListener("click", () => {
infoWindow.setContent(`<h3>${feature.properties.name}</h3>`);
infoWindow.open(map, marker);
});
return marker;
}
function debounce(callback, timeout) {
let timer;
return (...args) => {
clearTimeout(timer);
timer = setTimeout(() => {
callback(...args);
}, timeout);
};
}
window.initMap = initMap;
/*
* Always set the map height explicitly to define the size of the div element
* that contains the map.
*/
#map {
height: 100%;
}
/*
* Optional: Makes the sample page fill the window.
*/
html,
body {
height: 100%;
margin: 0;
padding: 0;
font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, Segoe UI, Roboto, Helvetica Neue, Arial, Noto Sans, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol, Noto Color Emoji;
}
<html>
<head>
<title>Map Clustering with GeoJSON</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta charset="utf-8" />
<link rel="stylesheet" type="text/css" href="./style.css" />
<script type="module" src="./index.js"></script>
</head>
<body>
<!--The div element for the map -->
<div id="map"></div>
<script
src="https://sdk.woosmap.com/map/map.js?key=woos-48c80350-88aa-333e-835a-07f4b658a9a4&callback=initMap"
defer
></script>
</body>
</html>
Running the Sample Locally
Before you can run this sample on your local machine, you need to have Git and Node.js installed. If they’re not already installed, follow these instructions to get them set up.
Once you have Git and Node.js installed, you can run the sample by following these steps:
-
Clone the repository and navigate to the directory of the sample.
-
Install the necessary dependencies.
-
Start running the sample.
Here are the commands you can use in your terminal to do this:
git clone -b sample/map-clustering-geojson https://github.com/woosmap/js-samples.git
cd js-samples
npm i
npm start
You can experiment with other samples by switching to any branch that starts with the pattern sample/SAMPLE_NAME.
git checkout sample/SAMPLE_NAME
npm i
npm start
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