Get Cluster
geojson
FeatureCollection GeoJSON Featuresfilter
any Filter used on GeoJSON properties to get Cluster
var geojson = turf.featureCollection([
turf.point([0, 0], {'marker-symbol': 'circle'}),
turf.point([2, 4], {'marker-symbol': 'star'}),
turf.point([3, 6], {'marker-symbol': 'star'}),
turf.point([5, 1], {'marker-symbol': 'square'}),
turf.point([4, 2], {'marker-symbol': 'circle'})
]);
// Create a cluster using K-Means (adds `cluster` to GeoJSON properties)
var clustered = turf.clustersKmeans(geojson);
// Retrieve first cluster (0)
var cluster = turf.getCluster(clustered, {cluster: 0});
//= cluster
// Retrieve cluster based on custom properties
turf.getCluster(clustered, {'marker-symbol': 'circle'}).length;
//= 2
turf.getCluster(clustered, {'marker-symbol': 'square'}).length;
//= 1
Returns FeatureCollection Single Cluster filtered by GeoJSON Properties
Callback for clusterEach
Type: Function
cluster
FeatureCollection? The current cluster being processed.clusterValue
any? Value used to create cluster being processed.currentIndex
number? The index of the current element being processed in the array.Starts at index 0
Returns void
clusterEach
geojson
FeatureCollection GeoJSON Featuresproperty
(string | number) GeoJSON property key/value used to create clusterscallback
Function a method that takes (cluster, clusterValue, currentIndex)
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
turf.clusterEach(clustered, 'cluster', function (cluster, clusterValue, currentIndex) {
//= cluster
//= clusterValue
//= currentIndex
})
// Calculate the total number of clusters
var total = 0
turf.clusterEach(clustered, 'cluster', function () {
total++;
});
// Create an Array of all the values retrieved from the 'cluster' property
var values = []
turf.clusterEach(clustered, 'cluster', function (cluster, clusterValue) {
values.push(clusterValue);
});
Returns void
Callback for clusterReduce
The first time the callback function is called, the values provided as arguments depend on whether the reduce method has an initialValue argument.
If an initialValue is provided to the reduce method:
- The previousValue argument is initialValue.
- The currentValue argument is the value of the first element present in the array.
If an initialValue is not provided:
- The previousValue argument is the value of the first element present in the array.
- The currentValue argument is the value of the second element present in the array.
Type: Function
previousValue
any? The accumulated value previously returned in the last invocation of the callback, or initialValue, if supplied.cluster
FeatureCollection? The current cluster being processed.clusterValue
any? Value used to create cluster being processed.currentIndex
number? The index of the current element being processed in the array. Starts at index 0, if an initialValue is provided, and at index 1 otherwise.
Reduce clusters in GeoJSON Features, similar to Array.reduce()
geojson
FeatureCollection GeoJSON Featuresproperty
(string | number) GeoJSON property key/value used to create clusterscallback
Function a method that takes (previousValue, cluster, clusterValue, currentIndex)initialValue
any? Value to use as the first argument to the first call of the callback.
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);
}, []);
Returns any The value that results from the reduction.
This module is part of the Turfjs project, an open source module collection dedicated to geographic algorithms. It is maintained in the Turfjs/turf repository, where you can create PRs and issues.
Install this single module individually:
$ npm install @turf/clusters
Or install the all-encompassing @turf/turf module that includes all modules as functions:
$ npm install @turf/turf