clusterReduce

Description

Reduce clusters in GeoJSON Features, similar to Array.reduce()

Parameters

Name	Type	Description
geojson	FeatureCollection	GeoJSON Features
property	string | number	GeoJSON property key/value used to create clusters
callback	clusterReduceCallback	a method that takes (previousValue, cluster, clusterValue, currentIndex)
initialValue?	any	Value to use as the first argument to the first call of the callback.

Returns

any The value that results from the reduction.

Examples

var geojson = turf.featureCollection([
  turf.point([0, 0]),
  turf.point([2, 4]),
  turf.point([3, 6]),
  turf.point([5, 1]),
  turf.point([4, 2]),
]);

// Create a cluster using K-Means (adds `cluster` to GeoJSON properties)
var clustered = turf.clustersKmeans(geojson);

// Iterate over each cluster and perform a calculation
var initialValue = 0;
turf.clusterReduce(
  clustered,
  "cluster",
  function (previousValue, cluster, clusterValue, currentIndex) {
    //=previousValue
    //=cluster
    //=clusterValue
    //=currentIndex
    return previousValue++;
  },
  initialValue,
);

// Calculate the total number of clusters
var total = turf.clusterReduce(
  clustered,
  "cluster",
  function (previousValue) {
    return previousValue++;
  },
  0,
);

// Create an Array of all the values retrieved from the 'cluster' property
var values = turf.clusterReduce(
  clustered,
  "cluster",
  function (previousValue, cluster, clusterValue) {
    return previousValue.concat(clusterValue);
  },
  [],
);

Installation

$ npm install @turf/clusters

import { clusterReduce } from "@turf/clusters";
const result = clusterReduce(...);

$ npm install @turf/turf

import * as turf from "@turf/turf";
const result = turf.clusterReduce(...);