Question

Reduce clusters in GeoJSON Features, similar to Array.reduce()
简化GeoJSON要素中的聚类，类似于 Array.reduce() 方法。

> npm install @turf/clusters

参数

参数	类型	描述
geojson	FeatureCollection	GeoJSON Features
property	(string|number)	GeoJSON property key/value used to create clusters
callback	Function	a method that takes (previousValue, cluster, clusterValue, currentIndex)
initialValue	(*)	Value to use as the first argument to the first call of the callback.

返回

• • The value that results from the reduction.

示例

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);
}, []);