Clustering - filter popup features

Explore in the sandbox

View live

This sample demonstrates how to query and filter features represented by clusters using Arcade expressions in a cluster's popup.

Typically clusters display basic summary information about all features in the cluster, such as the total number of features, the predominant type, or the average value of a numeric field. Sometimes you may want to display information about a subset of important features, such as the number of fatalities in a cluster representing car crashes.

The cluster popup in this example displays the total number of power plants that generate power with coal, along with the amount of power they produce as a ratio to all power produced in the cluster. This is all accomplished with Arcade expressions. Within the context of a cluster popup, you can use Arcade to filter a cluster's features and perform statistics on those features.

Use Arcade to summarize clusters

Arcade expressions in cluster popups give you access to the cluster graphic itself (i.e. $feature) and the features that make up the cluster (i.e. $aggregatedFeatures).

$feature

The $feature profile variable allows you to reference aggregate fields used by the renderer, such as $feature.cluster_count. If the renderer visualizes population with a numeric POP field, you will have access to the average population of features in the cluster by referencing $feature.cluster_avg_POP within the expression.

$aggregatedFeatures

The $aggregatedFeatures profile variable represents all features included in the cluster. You can use this profile variable to iterate through features, filter them, and calculate statistics with the features.

Use dark colors for code blocksCopy
// returns the total number of features in the cluster // this will be the same as $feature.cluster_count Count($aggregatedFeatures)

Use dark colors for code blocksCopy
// returns the count of features of fuel type 'Coal' within the cluster Count(Filter($aggregatedFeatures, "fuel1 = 'Coal'"))

The Expects Arcade function tells the clustered layer to request extra fields required for the popup to function properly.

Use dark colors for code blocksCopy
// returns the amount of power generated by coal power plants // as a percentage of total power produced in the cluster along // with the total number of coal power plants  // Since the capacity_mw field may not be available on the client // at runtime, we tell the Arcade engine to request it from the layer Expects($aggregatedFeatures, "capacity_mw") var mWtotal = Sum($aggregatedFeatures, "capacity_mw"); var mWCoal = Sum(Filter($aggregatedFeatures, "fuel1 = 'Coal'"), "capacity_mw"); if(mWCoal < 1){  return "none"; } var mWratio = Round(mWCoal / mWtotal, 4); return \`\${Text(mWratio, "#.#%")} (\${Text(mWCoal, "#,### mW")})\`;  // the output will look like "15% (6,500 mW)"

To use values returned from Arcade expressions within a popup, you must set the Arcade expressions in the expressionInfos property of the popupTemplate, then reference it using the {expression/expression-name} syntax.

Calculate cluster statistics
Use dark colors for code blocksCopy
91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 122 
 let popupTemplate = {  title: "Coal summary",  content: `<p>This cluster represents <b>{cluster_count}</b> power plants. <b>{expression/Coal-count}</b> of these plants are fueled by Coal.</p><p>Coal plants produce <b>{expression/Coal-mw-sum}</b> of the total power generated in this cluster.</p>`,  expressionInfos: [  {  name: "Coal-count",  title: "Coal-count",  expression: `  // returns the total number of coal power plants  Count(Filter($aggregatedFeatures, "fuel1 = 'Coal'"))  `,  },  {  name: "Coal-mw-sum",  title: "Coal-mw-sum",  expression: `  // returns the amount of electricity generated by coal  // in this cluster as a ratio to the total capacity  // of plants included in the cluster  Expects($aggregatedFeatures, "capacity_mw")  var mWtotal = Sum($aggregatedFeatures, "capacity_mw");  var mWCoal = Sum(Filter($aggregatedFeatures, "fuel1 = 'Coal'"), "capacity_mw");  if(mWCoal < 1){  return "none";  }  var mWratio = Round(mWCoal / mWtotal, 4);  return \`\${Text(mWratio, "#.#%")} (\${Text(mWCoal, "#,### mW")})\`;  `,  },  ],  }; 

Intro to clustering

Clustering - generate suggested configuration

Clustering - query clusters

Clustering - advanced configuration

Popup charts for clusters

This sample demonstrates how to summarize clustered features using charts within a cluster's popup.

Clustering with visual variables

FeatureReductionCluster

Read the Core API Reference for more information.