@jingsam/supercluster v5.0.0

supercluster

This repository is a fork of mapbox/supercluster, but for CGCS2000 projection.

A very fast JavaScript library for geospatial point clustering for browsers and Node.

<script src="https://unpkg.com/supercluster@4.1.1/dist/supercluster.min.js"></script>

var index = supercluster({
    radius: 40,
    maxZoom: 16
});
index.load(points);
index.getClusters([-180, -85, 180, 85], 2);

Clustering 6 million points in Leaflet:

Install

Install using NPM (npm install supercluster) or Yarn (yarn add supercluster), then:

// import as a ES module
import supercluster from 'supercluster';

// or require in Node / Browserify
const supercluster = require('supercluster');

Or use a browser build directly:

<script src="https://unpkg.com/supercluster@4.1.1/dist/supercluster.min.js"></script>

Methods

load(points)

Loads an array of GeoJSON Feature objects. Each feature's geometry must be a GeoJSON Point. Once loaded, index is immutable.

getClusters(bbox, zoom)

For the given bbox array ([westLng, southLat, eastLng, northLat]) and integer zoom, returns an array of clusters and points as GeoJSON Feature objects.

getTile(z, x, y)

For a given zoom and x/y coordinates, returns a geojson-vt-compatible JSON tile object with cluster/point features.

getChildren(clusterId)

Returns the children of a cluster (on the next zoom level) given its id (cluster_id value from feature properties).

getLeaves(clusterId, limit = 10, offset = 0)

Returns all the points of a cluster (given its cluster_id), with pagination support: limit is the number of points to return (set to Infinity for all points), and offset is the amount of points to skip (for pagination).

getClusterExpansionZoom(clusterId)

Returns the zoom on which the cluster expands into several children (useful for "click to zoom" feature) given the cluster's cluster_id.

Options

Property map/reduce options

In addition to the options above, supercluster supports property aggregation with the following three options:

• initial: a function that returns an object with cluster's initial properties.
• map: a function that returns properties to use for individual points.
• reduce: a reduce function for calculating properties in clusters.

Example of setting up a sum cluster property that accumulates the sum of myValue property values:

var index = supercluster({
    initial: function() { return {sum: 0}; },
    map: function(props) { return {sum: props.myValue}; },
    reduce: function(accumulated, props) { accumulated.sum += props.sum; }
});

Developing Supercluster

npm install       # install dependencies
npm run build     # generate dist/supercluster.js and dist/supercluster.min.js
npm test          # run tests