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Display a web map with a point feature layer that has feature reduction enabled to aggregate points into clusters.

Image of display clusters

Use case

Feature clustering can be used to dynamically aggregate groups of points that are within proximity of each other in order to represent each group with a single symbol. Such grouping allows you to see patterns in the data that are difficult to visualize when a layer contains hundreds or thousands of points that overlap and cover each other.

How to use the sample

Pan and zoom the map to view how clustering is dynamically updated. Toggle clustering off to view the original point features that make up the clustered elements. When clustering is On, you can click on a clustered geoelement to view aggregated information and summary statistics for that cluster. When clustering is toggled off and you click on the original feature you get access to information about individual power plant features.

How it works

  1. Create a map from a web map PortalItem.
  2. Get the cluster enabled layer from the map’s operational layers.
  3. Get the FeatureReduction from the feature layer and call setEnabled(boolean enabled) to enable or disable clustering on the feature layer.
  4. When the user clicks on the map, call identifyLayerAsync on the feature layer and pass in the map click location.
  5. Get the Popup from the resulting IdentifyLayerResult.
  6. Get the popup’s getDescription and using a WebView inside a VBox, display it by setting the callout’s setCustomView.

Relevant API

  • AggregateGeoElement
  • FeatureLayer
  • FeatureReduction
  • GeoElement
  • IdentifyLayerResult

About the data

This sample uses a web map that displays the Esri Global Power Plants feature layer with feature reduction enabled. When enabled, the aggregate features symbology shows the color of the most common power plant type, and a size relative to the average plant capacity of the cluster.

Tags

aggregate, bin, cluster, group, merge, normalize, reduce, summarize

Sample Code

module-info.java module-info.java DisplayClustersSample.java
/*
* Copyright 2024 Esri.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
module com.esri.samples.display_clusters {
// require ArcGIS Maps SDK for Java module
requires com.esri.arcgisruntime;
// handle SLF4J http://www.slf4j.org/codes.html#StaticLoggerBinder
requires org.slf4j.nop;
// require JavaFX modules that the application uses
requires javafx.graphics;
requires javafx.web;
exports com.esri.samples.display_clusters;
}