@turf/clusters

getCluster

Get Cluster

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* geojson [FeatureCollection][1] GeoJSON Features
* filter any Filter used on GeoJSON properties to get Cluster

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``javascript
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][1] Single Cluster filtered by GeoJSON Properties

clusterEachCallback

Callback for clusterEach

Type: [Function][2]

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* cluster [FeatureCollection][1]? The current cluster being processed.
* clusterValue any? Value used to create cluster being processed.
* currentIndex [number][3]? The index of the current element being processed in the array.Starts at index 0

Returns void

clusterEach

clusterEach

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* geojson [FeatureCollection][1] GeoJSON Features
* property ([string][4] | [number][3]) GeoJSON property key/value used to create clusters
* callback [clusterEachCallback][5] a method that takes (cluster, clusterValue, currentIndex)

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`javascript
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

clusterReduceCallback

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][2]

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* previousValue any? The accumulated value previously returned in the last invocation
of the callback, or initialValue, if supplied.
* cluster [FeatureCollection][1]? The current cluster being processed.
* clusterValue any? Value used to create cluster being processed.
* currentIndex [number][3]? 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.

Returns void

clusterReduce

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

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* geojson [FeatureCollection][1] GeoJSON Features
* property ([string][4] | [number][3]) GeoJSON property key/value used to create clusters
* callback [clusterReduceCallback][6] a method that takes (previousValue, cluster, clusterValue, currentIndex)
* initialValue any? Value to use as the first argument to the first call of the callback.

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`javascript
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.

[1]: https://tools.ietf.org/html/rfc7946#section-3.3

[2]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function

[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number

[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String

[5]: #clustereachcallback

[6]: #clusterreducecallback

---

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.

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Install this single module individually:

`sh
$ npm install @turf/clusters
`

Or install the all-encompassing @turf/turf module that includes all modules as functions:

`sh
$ npm install @turf/turf
``