ol-supercluster

OpenLayers Super Cluster

This library basically integrates OpenLayers with SuperCluster. The purpose is to allow faster and precise clustering on OpenLayers in a way that's compatible with OpenLayers's Cluster Source, with only a few additional changes. It's composed by just one class, which can be used instead of ol.Source.Cluster, and that receives one additional required parameter: view, which is precisely Map's View.

Installation

The installation of this package is very simple: In fact, it can be installed by just running:

    npm install --save ol-supercluster

If using NodeJS (this installs the package based purely on ES 6), or:

    bower install --save ol-supercluster

If you want to use this package in the browser. You can also use the version provided by a CDN, like JSDelivr. So you can paste the code below on a page and start using ol-supercluster really fast:

<script language="javascript" type="text/javascript" src="https://cdn.jsdelivr.net/npm/ol-supercluster@latest/dist/ol-supercluster.js"></script>

WARNING: Please note that the code above uses always the latest version of ol-supercluster. In production, please replace latest with a valid version number from the Releases page or use NPM to install a fixed version for you. =)

Usage

To use this library, you basically can instance the constructor in a way very similar to how ol/source/Cluster works:

import { Map as OlMap } from "ol";
import { toLonLat } from 'ol/proj';
import { Vector as VectorSource } from 'ol/source';
import SuperCluster from 'ol-supercluster';

const map = new OlMap({
    // Your usual openlayers map here
});

const features = new VectorSource();

const cluster = new SuperCluster({
    source: features, // Required parameter to define the source of the features to pass to SuperCluster
    view: map.getView(), // Required parameter, usually got by `map.getView()`, used to compute some parameters passed into SuperCluster's algorithm
    radius: 60, // Optional parametern to define the  cluster radius, as refered in SuperCluster documentation, the default value is 60
    geoJsonFunction: function(feature) {
        const geometry = feature.getGeometry();
        return {
            "type": "Feature",
            "properties":  null,
            "geometry": {
                "type": "Point",
                "coordinates": toLonLat(geometry.getCoordinates())
            }
        };
    }, // Optional parameter that allows to convert an OpenLayers Feature into a GeoJSON feature whose geometry is a Point, as supported by SuperCluster (for instance, you may get the center of your geometry here, for example)
});

After (or even before) you initialize SuperCluster source, you can just add features with points to your features VectorSource, like that:

import { Feature } from 'ol';
import { Point } from 'ol/geom';
import { fromLonLat } from 'ol/proj';
const longitude = -43.2315809;
const latitude = -22.9139167;
features.addFeature(new Feature(new Point(fromLonLat([longitude, latitude]))))

You can pass the created cluster to any Layer that works with VectorSource, like for instance ol-ext's AnimatedCluster:

import AnimatedCluster from "ol-ext/layer/AnimatedCluster";

const layerCluster = new AnimatedCluster({
    source: cluster,
    // other AnimatedCluster parameters..
});

Or even openlayers's VectorLayer:

import { Vector as VectorLayer } from 'ol/layer';

const layerCluster = new VectorLayer({
    source: cluster,
    // other VectorLayer parameters...
});

Contributing

We still must work on improving documentation, adding tutorial, examples and tests. Feel free to contribute with Pull Requests:

• Documentation;
• Tutorial;
• Examples;
• Tests;