# Class: Cluster

This documentation is for OpenLayers v10.9.0. The latest is v.

## ol/source/Cluster~Cluster

    import Cluster from 'ol/source/Cluster.js';

Layer source to cluster vector data. Works out of the box with point geometries. For other geometry types, or if not all geometries should be considered for clustering, a custom `geometryFunction` can be defined.

If the instance is disposed without also disposing the underlying source `setSource(null)` has to be called to remove the listener reference from the wrapped source.

#### new Cluster(options)

source/Cluster.js, line 77

  Name | Type | Description
  --- | --- | ---
  `attributions` | AttributionLike | undefined | Attributions.
  `distance` | number (defaults to 20) | Distance in pixels within which features will be clustered together.
  `minDistance` | number (defaults to 0) | Minimum distance in pixels between clusters. Will be capped at the configured distance. By default no minimum distance is guaranteed. This config can be used to avoid overlapping icons. As a tradoff, the cluster feature's position will no longer be the center of all its features.
  `geometryFunction` | GeometryFunction<FeatureType> | undefined | Function that takes a `Feature` as argument and returns a `Point` as cluster calculation point for the feature. When a feature should not be considered for clustering, the function should return `null`. The default, which works when the underlying source contains point features only, is
      function(feature) {
        return feature.getGeometry();
      }
  See `getInteriorPoint` for a way to get a cluster calculation point for polygons.
  `createCluster` | function | undefined | Function that takes the cluster's center `Point` and an array of `Feature` included in this cluster. Must return a `Feature` that will be used to render. Default implementation is:
      function(point, features) {
        return new Feature({
          geometry: point,
          features: features
        });
      }
  `source` | VectorSource<FeatureType> (defaults to null) | Source.
  `wrapX` | boolean (defaults to true) | Whether to wrap the world horizontally.

  ##### Fires:

  - `addfeature` (VectorSourceEvent) - Triggered when a feature is added to the source.
  - `change` (BaseEvent) - Generic change event. Triggered when the revision counter is increased.
  - `changefeature` (VectorSourceEvent) - Triggered when a feature is updated.
  - `clear` (VectorSourceEvent) - Triggered when the clear method is called on the source.
  - `error` (BaseEvent) - Generic error event. Triggered when an error occurs.
  - `featuresloadend` (VectorSourceEvent) - Triggered when features finishes loading.
  - `featuresloaderror` (VectorSourceEvent) - Triggered if feature loading results in an error.
  - `featuresloadstart` (VectorSourceEvent) - Triggered when features starts loading.
  - `propertychange` (ObjectEvent) - Triggered when a property is changed.
  - `removefeature` (VectorSourceEvent) - Triggered when a feature is removed from the source. See `source.clear()` for exceptions.

### Extends

- VectorSource

### Methods

#### addFeature(feature) inherited

source/Vector.js, line 328

  Add a single feature to the source. If you want to add a batch of features at once, call `#addFeatures()` instead. A feature will not be added to the source if feature with the same id is already there. The reason for this behavior is to avoid feature duplication when using bbox or tile loading strategies. Note: this also applies if a `Collection` is used for features, meaning that if a feature with a duplicate id is added in the collection, it will be removed from it right away.

  Name | Type | Description
  --- | --- | ---
  `feature` | FeatureType | Feature to add.

#### addFeatures(features) inherited

source/Vector.js, line 426

  Add a batch of features to the source.

  Name | Type | Description
  --- | --- | ---
  `features` | Array.<FeatureType> | Features to add.

#### changed() inherited

Observable.js, line 68

  Increases the revision counter and dispatches a 'change' event.

#### clear(fast)

source/Cluster.js, line 160

  Remove all features from the source.

  Name | Type | Description
  --- | --- | ---
  `fast` | boolean | undefined | Skip dispatching of `removefeature` events.

#### dispatchEvent(event){boolean | undefined} inherited

events/Target.js, line 85

  Dispatches an event and calls all listeners listening for events of this type. The event parameter can either be a string or an Object with a `type` property.

  Name | Type | Description
  --- | --- | ---
  `event` | BaseEvent | string | Event object.

  ##### Returns:

  `false` if anyone called preventDefault on the event object or if any of the listeners returned false.

#### forEachFeature(callback){T | undefined} inherited

source/Vector.js, line 591

  Iterate through all features on the source, calling the provided callback with each one. If the callback returns any "truthy" value, iteration will stop and the function will return the same value. Note: this function only iterate through the feature that have a defined geometry.

  Name | Type | Description
  --- | --- | ---
  `callback` | function | Called with each feature on the source. Return a truthy value to stop iteration.

  ##### Returns:

  The return value from the last call to the callback.

#### forEachFeatureInExtent(extent, callback){T | undefined} inherited

source/Vector.js, line 648

  Iterate through all features whose bounding box intersects the provided extent (note that the feature's geometry may not intersect the extent), calling the callback with each feature. If the callback returns a "truthy" value, iteration will stop and the function will return the same value.

  If you are interested in features whose geometry intersects an extent, call the `#forEachFeatureIntersectingExtent()` method instead.

  When `useSpatialIndex` is set to false, this method will loop through all features, equivalent to `#forEachFeature()`.

  Name | Type | Description
  --- | --- | ---
  `extent` | Extent | Extent.
  `callback` | function | Called with each feature whose bounding box intersects the provided extent.

  ##### Returns:

  The return value from the last call to the callback.

#### forEachFeatureIntersectingExtent(extent, callback){T | undefined} inherited

source/Vector.js, line 672

  Iterate through all features whose geometry intersects the provided extent, calling the callback with each feature. If the callback returns a "truthy" value, iteration will stop and the function will return the same value.

  If you only want to test for bounding box intersection, call the `#forEachFeatureInExtent()` method instead.

  Name | Type | Description
  --- | --- | ---
  `extent` | Extent | Extent.
  `callback` | function | Called with each feature whose geometry intersects the provided extent.

  ##### Returns:

  The return value from the last call to the callback.

#### get(key){*} inherited

Object.js, line 136

  Gets a value.

  Name | Type | Description
  --- | --- | ---
  `key` | string | Key name.

  ##### Returns:

  Value.

#### getAttributions(){Attribution} inherited

source/Source.js, line 129

  Get the attribution function for the source.

  ##### Returns:

  Attribution function.

#### getAttributionsCollapsible(){boolean} inherited

source/Source.js, line 137

  ##### Returns:

  Attributions are collapsible.

#### getClosestFeatureToCoordinate(coordinate, filter){FeatureType | null} inherited

source/Vector.js, line 786

  Get the closest feature to the provided coordinate.

  This method is not available when the source is configured with `useSpatialIndex` set to `false` and the features in this source are of type `Feature`.

  Name | Type | Description
  --- | --- | ---
  `coordinate` | Coordinate | Coordinate.
  `filter` | function | undefined | Feature filter function. The filter function will receive one argument, the `feature` and it should return a boolean value. By default, no filtering is made.

  ##### Returns:

  Closest feature (or `null` if none found).

#### getDistance(){number}

source/Cluster.js, line 170

  Get the distance in pixels between clusters.

  ##### Returns:

  Distance.

#### getExtent(extent){Extent | null} inherited

source/Vector.js, line 842

  Get the extent of the features currently in the source.

  This will return `null` when the source is configured with `useSpatialIndex` set to `false`.

  Name | Type | Description
  --- | --- | ---
  `extent` | Extent | undefined | Destination extent. If provided, no new extent will be created. Instead, that extent's coordinates will be overwritten.

  ##### Returns:

  Extent.

#### getFeatureById(id){FeatureClassOrArrayOfRenderFeatures<FeatureType> | null} inherited

source/Vector.js, line 858

  Get a feature by its identifier (the value returned by feature.getId()). When `RenderFeature`s are used, `getFeatureById()` can return an array of `RenderFeature`s. This allows for handling of `GeometryCollection` geometries, where format readers create one `RenderFeature` per `GeometryCollection` member. Note that the index treats string and numeric identifiers as the same. So `source.getFeatureById(2)` will return a feature with id `'2'` or `2`.

  Name | Type | Description
  --- | --- | ---
  `id` | string | number | Feature identifier.

  ##### Returns:

  The feature (or `null` if not found).

#### getFeatures(){Array.<FeatureType>} inherited

source/Vector.js, line 711

  Get a snapshot of the features currently on the source in random order. The returned array is a copy, the features are references to the features in the source.

  ##### Returns:

  Features.

#### getFeaturesAtCoordinate(coordinate){Array.<FeatureType>} inherited

source/Vector.js, line 730

  Get all features whose geometry intersects the provided coordinate.

  Name | Type | Description
  --- | --- | ---
  `coordinate` | Coordinate | Coordinate.

  ##### Returns:

  Features.

#### getFeaturesCollection(){Collection<FeatureType> | null} inherited

source/Vector.js, line 701

  Get the features collection associated with this source. Will be `null` unless the source was configured with `useSpatialIndex` set to `false`, or with a `Collection` as `features`.

  ##### Returns:

  The collection of features.

#### getFeaturesInExtent(extent, projection){Array.<FeatureType>} inherited

source/Vector.js, line 753

  Get all features whose bounding box intersects the provided extent. Note that this returns an array of all features intersecting the given extent in random order (so it may include features whose geometries do not intersect the extent).

  When `useSpatialIndex` is set to false, this method will return all features.

  Name | Type | Description
  --- | --- | ---
  `extent` | Extent | Extent.
  `projection` | Projection | undefined | Include features where `extent` exceeds the x-axis bounds of `projection` and wraps around the world.

  ##### Returns:

  Features.

#### getFormat(){FeatureFormat<FeatureType> | null} inherited

source/Vector.js, line 884

  Get the format associated with this source.

  ##### Returns:

  } The feature format.

#### getKeys(){Array.<string>} inherited

Object.js, line 149

  Get a list of object property names.

  ##### Returns:

  List of property names.

#### getMinDistance(){number}

source/Cluster.js, line 221

  The configured minimum distance between clusters.

  ##### Returns:

  The minimum distance in pixels.

#### getProjection(){Projection | null} inherited

source/Source.js, line 146

  Get the projection of the source.

  ##### Returns:

  Projection.

#### getProperties(){NoInfer.<Properties>} inherited

Object.js, line 158

  Get an object of all property names and values.

  ##### Returns:

  Object.

#### getRevision(){number} inherited

Observable.js, line 79

  Get the version number for this object. Each time the object is modified, its version number will be incremented.

  ##### Returns:

  Revision.

#### getSource(){VectorSource<FeatureType> | null}

source/Cluster.js, line 179

  Get a reference to the wrapped source.

  ##### Returns:

  Source.

#### getState(){State} inherited

source/Source.js, line 170

  Get the state of the source, see `State` for possible states.

  ##### Returns:

  State.

#### getUrl(){string | FeatureUrlFunction | undefined} inherited

source/Vector.js, line 901

  Get the url associated with this source.

  ##### Returns:

  The url.

#### hasFeature(feature){boolean} inherited

source/Vector.js, line 956

  Returns true if the feature is contained within the source.

  Name | Type | Description
  --- | --- | ---
  `feature` | FeatureType | Feature.

  ##### Returns:

  Has feature.

#### on(type, listener){EventsKey | Array<EventsKey>} inherited

Observable.js, line 152

  Listen for a certain type of event.

  Name | Type | Description
  --- | --- | ---
  `type` | string | Array.<string> | The event type or array of event types.
  `listener` | function | The listener function.

  ##### Returns:

  Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

#### once(type, listener){EventsKey | Array<EventsKey>} inherited

Observable.js, line 164

  Listen once for a certain type of event.

  Name | Type | Description
  --- | --- | ---
  `type` | string | Array.<string> | The event type or array of event types.
  `listener` | function | The listener function.

  ##### Returns:

  Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

#### removeFeature(feature) inherited

source/Vector.js, line 1105

  Remove a single feature from the source. If you want to batch remove features, use the `#removeFeatures()` method instead.

  Name | Type | Description
  --- | --- | ---
  `feature` | FeatureType | Feature to remove.

#### removeFeatures(features) inherited

source/Vector.js, line 1088

  Batch remove features from the source. If you want to remove all features at once, use the `#clear()` method instead.

  Name | Type | Description
  --- | --- | ---
  `features` | Array.<FeatureType> | Features to remove.

#### removeLoadedExtent(extent) inherited

source/Vector.js, line 1069

  Remove an extent from the list of loaded extents.

  Name | Type | Description
  --- | --- | ---
  `extent` | Extent | Extent.

#### set(key, value, silent) inherited

Object.js, line 218

  Sets a value.

  Name | Type | Description
  --- | --- | ---
  `key` | string | Key name.
  `value` | * | Value.
  `silent` | boolean | undefined | Update without triggering an event.

#### setAttributions(attributions) inherited

source/Source.js, line 203

  Set the attributions of the source.

  Name | Type | Description
  --- | --- | ---
  `attributions` | AttributionLike | undefined | Attributions. Can be passed as `string`, `Array<string>`, `Attribution`, or `undefined`.

#### setDistance(distance)

source/Cluster.js, line 202

  Set the distance within which features will be clusterd together.

  Name | Type | Description
  --- | --- | ---
  `distance` | number | The distance in pixels.

#### setLoader(loader) inherited

source/Vector.js, line 1182

  Set the new loader of the source. The next render cycle will use the new loader.

  Name | Type | Description
  --- | --- | ---
  `loader` | FeatureLoader | The loader to set.

#### setMinDistance(minDistance)

source/Cluster.js, line 212

  Set the minimum distance between clusters. Will be capped at the configured distance.

  Name | Type | Description
  --- | --- | ---
  `minDistance` | number | The minimum distance in pixels.

#### setProperties(values, silent) inherited

Object.js, line 238

  Sets a collection of key-value pairs. Note that this changes any existing properties and adds new ones (it does not remove any existing properties).

  Name | Type | Description
  --- | --- | ---
  `values` | Partial.<NoInfer.<Properties>> | Values.
  `silent` | boolean | undefined | Update without triggering an event.

#### setSource(source)

source/Cluster.js, line 230

  Replace the wrapped source.

  Name | Type | Description
  --- | --- | ---
  `source` | VectorSource<FeatureType> | null | The new source for this instance.

#### setUrl(url) inherited

source/Vector.js, line 1191

  Points the source to a new url. The next render cycle will use the new url.

  Name | Type | Description
  --- | --- | ---
  `url` | string | FeatureUrlFunction | Url.

#### un(type, listener) inherited

Observable.js, line 173

  Unlisten for a certain type of event.

  Name | Type | Description
  --- | --- | ---
  `type` | string | Array.<string> | The event type or array of event types.
  `listener` | function | The listener function.

#### unset(key, silent) inherited

Object.js, line 262

  Unsets a property.

  Name | Type | Description
  --- | --- | ---
  `key` | string | Key name.
  `silent` | boolean | undefined | Unset without triggering an event.