OpenLayers. Strategy. Cluster

Strategy for vector feature clustering.

Inherits from

Summary
OpenLayers. Strategy. ClusterStrategy for vector feature clustering.
Properties
layer{OpenLayers.Layer.Vector} The layer that this strategy is assigned to.
distance{Integer} Pixel distance between features that should be considered a single cluster.
features{Array(OpenLayers.Feature.Vector)} Cached features.
clusters{Array(OpenLayers.Feature.Vector)} Calculated clusters.
clustering{Boolean} The strategy is currently clustering features.
resolution{Float} The resolution (map units per pixel) of the current cluster set.
Constructor
OpenLayers. Strategy. ClusterCreate a new clustering strategy.
Functions
activateActivate the strategy.
deactivateDeactivate the strategy.
cacheFeaturesCache features before they are added to the layer.
clearCacheClear out the cached features.
clusterCluster features based on some threshold distance.
clustersExistDetermine whether calculated clusters are already on the layer.
shouldClusterDetermine whether to include a feature in a given cluster.
addToClusterAdd a feature to a cluster.
createClusterGiven a feature, create a cluster.

Properties

layer

{OpenLayers.Layer.Vector} The layer that this strategy is assigned to.

distance

{Integer} Pixel distance between features that should be considered a single cluster.  Default is 20 pixels.

features

{Array(OpenLayers.Feature.Vector)} Cached features.

clusters

{Array(OpenLayers.Feature.Vector)} Calculated clusters.

clustering

{Boolean} The strategy is currently clustering features.

resolution

{Float} The resolution (map units per pixel) of the current cluster set.

Constructor

OpenLayers. Strategy. Cluster

Create a new clustering strategy.

Parameters

options{Object} Optional object whose properties will be set on the instance.

Functions

activate

activate: function()

Activate the strategy.  Register any listeners, do appropriate setup.

Returns

{Boolean} The strategy was successfully activated.

deactivate

deactivate: function()

Deactivate the strategy.  Unregister any listeners, do appropriate tear-down.

Returns

{Boolean} The strategy was successfully deactivated.

cacheFeatures

cacheFeatures: function(event)

Cache features before they are added to the layer.

Parameters

event{Object} The event that this was listening for.  This will come with a batch of features to be clustered.

Returns

{Boolean} False to stop layer from being added to the layer.

clearCache

clearCache: function()

Clear out the cached features.  This destroys features, assuming nothing else has a reference.

cluster

cluster: function()

Cluster features based on some threshold distance.

clustersExist

clustersExist: function()

Determine whether calculated clusters are already on the layer.

Returns

{Boolean} The calculated clusters are already on the layer.

shouldCluster

shouldCluster: function(cluster,
feature)

Determine whether to include a feature in a given cluster.

Parameters

cluster{OpenLayers.Feature.Vector} A cluster.
feature{OpenLayers.Feature.Vector} A feature.

Returns

{Boolean} The feature should be included in the cluster.

addToCluster

addToCluster: function(cluster,
feature)

Add a feature to a cluster.

Parameters

cluster{OpenLayers.Feature.Vector} A cluster.
feature{OpenLayers.Feature.Vector} A feature.

createCluster

createCluster: function(feature)

Given a feature, create a cluster.

Parameters

feature{OpenLayers.Feature.Vector}

Returns

{OpenLayers.Feature.Vector} A cluster.

Instances of OpenLayers.Layer.Vector are used to render vector data from a variety of sources.
Vector features use the OpenLayers.Geometry classes as geometry description.
activate: function()
Activate the strategy.
deactivate: function()
Deactivate the strategy.
cacheFeatures: function(event)
Cache features before they are added to the layer.
clearCache: function()
Clear out the cached features.
cluster: function()
Cluster features based on some threshold distance.
clustersExist: function()
Determine whether calculated clusters are already on the layer.
shouldCluster: function(cluster,
feature)
Determine whether to include a feature in a given cluster.
addToCluster: function(cluster,
feature)
Add a feature to a cluster.
createCluster: function(feature)
Given a feature, create a cluster.
Abstract vector layer strategy class.
Close