FeatureReductionBinning | API Reference | ArcGIS Maps SDK for JavaScript 4.31

Aggregates and summarizes dense features in a layer to bins in geographic space based on predefined geohashes. Binning is a method of representing the density of features in a grid of equally sized cells, or bins.

Binning should only be used as a visualization technique to reduce visual clutter because of many overlapping features or to provide a quick preview of feature density. It should not be used as a means of performing statistical analysis of data. As opposed to clustering, binning aggregates features in geographic space at a fixed level of detail. This means that the size of the bins does not change as the user zooms in and out of the map.

Display all features	Features aggregated to bins

Binning is typically used to visualize large point layers, but may be used with any geometry type (since version 4.31). In the case of binning polyline or polygon features, the centroid of the line or polygon is used to determine the bin in which it is placed. Individual parts comprising the intersection of line or polygon features to bins are not represented in the final bin statistics.

Usage guidelines

Use discretion when binning polygon and polyline features, as the underlying data could be misrepresented by the binning process.

Binning works best when features have a regular size smaller than the bin size. Irregularly shaped features may be misrepresented as some features may be placed in bins that do not contain the majority of the feature. As a result, some areas covered by large features may show no bins at all even though the area is completely covered by large features. As a guideline, small features like parcels, buildings, culverts, or connectors are well-suited for binning. Large, irregularly shaped features like counties, states, or countries do not need to be aggregated.

Known Limitations

Not supported in 3D SceneView.
Supported in FeatureLayer, CSVLayer, GeoJSONLayer, WFSLayer, and OGCFeatureLayer.
Not supported in all other layer types, including MapImageLayer.
Layer views with an applied FeatureEffect cannot be binned.

See also

Example

layer.featureReduction = {
  type: "binning",
  fields: [{
    name: "aggregateCount",
    statisticType: "count"
  }]
  renderer: {
    type: "simple",  // autocasts as new SimpleRenderer()
    symbol: {
      type: "simple-fill",  // autocasts as new SimpleFillSymbol()
      outline: {  // autocasts as new SimpleLineSymbol()
        width: 0.5,
        color: "white"
      }
    },
    visualVariables: [{
      type: "color",
      field: "aggregateCount",
      stops: [
        { value: 1, color: "white" },
        { value: 1000, color: "blue" }
      ]
    }]
  },
  popupTemplate: {
    content: "This bin contains <b>{aggregateCount}</b> features.",
    fieldInfos: [{
      fieldName: "aggregateCount",
      format: {
        digitSeparator: true,
        places: 0
      }
    }]
  }
};

Constructors

FeatureReductionBinning Constructor new FeatureReductionBinning(properties)

Parameter

properties Object

optional

See the properties for a list of all the properties that may be passed into the constructor.

Property Overview

Any properties can be set, retrieved or listened to. See the Watch for changes topic.

Show inherited properties

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Type	Summary	Class
String	The name of the class.	Accessor
AggregateField []	An array of aggregate fields that summarize layer fields from features contained within each bin.	FeatureReductionBinning
Number	The fixed geohash level used to create bins.	FeatureReductionBinning
LabelClass []\|null\|undefined	Defines labels for bins as an array of LabelClass.	FeatureReductionBinning
Boolean	Indicates whether to display labels for the bins.	FeatureReductionBinning
Number	Defines the maximum view scale at which binning is enabled.	FeatureReductionBinning
Boolean	Indicates whether to display a popup when a user clicks or touches a bin.	FeatureReductionBinning
PopupTemplate	The PopupTemplate to apply to bins.	FeatureReductionBinning
Renderer	The renderer used to style the bins.	FeatureReductionBinning
String	The feature reduction type.	FeatureReductionBinning

Property Details

declaredClass Inherited Property declaredClass Stringreadonly Inherited from Accessor

The name of the class. The declared class name is formatted as esri.folder.className.

fields Property fields AggregateField[]autocast Autocasts from Object []

An array of aggregate fields that summarize layer fields from features contained within each bin. These fields may be used by the popupTemplate, labelingInfo, and renderer.

Example

featureReduction.fields = [{
  name: "aggregateCount",
  statisticType: "count"
}, {
  name: "SUM_population",
  onStatisticField: "population",
  statisticType: "sum"
}, {
  name: "AVG_age",
  onStatisticField: "age",
  statisticType: "avg"
}, {
  name: "AVG_population_density",
  alias: "Average population density",
  onStatisticExpression: {
    expression: "$feature.population / AreaGeodetic($feature, 'square-miles')",
    title: "population density",
    returnType: "number"
  },
  statisticType: "avg"
}];

fixedBinLevel Property fixedBinLevel Number

The fixed geohash level used to create bins. Currently, bin sizes do not dynamically change as the user zooms in and out of the map. Larger numbers will create smaller bins. Levels range from 1 - 9. The following table suggests which bin level to use depending on the approximate view scale.

fixedBinLevel	view.scale
1	> 120,000,000
2	~88,000,000
3	~14,000,000
4	~3,000,000
5	~500,000
6	~84,000
7	~10,000
8	~3,000
9	~400

Default Value:3

Example

featureReduction.fixedBinLevel = 4;

labelingInfo Property labelingInfo LabelClass[] |null |undefinedautocast Autocasts from Object []

Defines labels for bins as an array of LabelClass. When set, labels independent of the layer.labelingInfo are used to convey information about each bin. This can include the count of all features in the bin, the average, or sum of a numeric attribute.

Any aggregate field defined in fields can be referenced in the label.

Multiple Label classes with different where clauses can be used to define several labels with varying styles on the same feature. Likewise, multiple label classes may be used to label different types of bins (e.g. blue labels for bins with few features and red labels for bins with many features).

Example

// Displays the count inside the bin
layer.featureReduction = {
  type: "binning",
  fields: [{
    name: "aggregateCount",
    statisticType: "count"
  }],
  labelingInfo: [{
    labelExpressionInfo: {
      expression: "$feature.aggregateCount"
    },
    symbol: {
      type: "text",
      color: "white",
      font: {
        size: "12px"
      },
      haloSize: 1,
      haloColor: "black"
    }
  }]
};

labelsVisible Property labelsVisible Boolean

Indicates whether to display labels for the bins. If true, labels will appear as defined in the labelingInfo property.

Default Value:true

Example

// Turns off bin labels, but preserves labelingInfo
const featureReduction = layer.featureReduction.clone();
featureReduction.labelsVisible = false;
layer.featureReduction = featureReduction;

maxScale Property maxScale Number Since: ArcGIS Maps SDK for JavaScript 4.26 FeatureReductionBinning since 4.24, maxScale added at 4.26.

Defines the maximum view scale at which binning is enabled. If the user zooms in beyond the scale specified here, binning will be disabled and only individual features will be displayed in the view. Once the user zooms out past this scale, binning will be re-enabled. A value of 0 means binning is always enabled, and therefore binning will be visible at all view scales.

Default Value:0

Example

// binning is disabled when the user zooms
// in beyond a 1:50,000 view scale
layer.featureReduction = {
  type: "binning",
  maxScale: 50000
};

popupEnabled Property popupEnabled Boolean

Indicates whether to display a popup when a user clicks or touches a bin. If false, the popup as defined in the popupTemplate will be persisted, but won't be displayed on click/tap.

Default Value:true

Example

// Turns off popups, but preserves popupTemplate
const featureReduction = layer.featureReduction.clone();
featureReduction.popupEnabled = false;
layer.featureReduction = featureReduction;

popupTemplate Property popupTemplate PopupTemplateautocast

The PopupTemplate to apply to bins. When set, a popupTemplate independent of the layer.popupTemplate is used. This popup can display summary information for each bin, such as feature count or any other field defined in fields.

The PopupTemplate may contain one or more Arcade expressions following the specification defined by the Arcade Feature Reduction Popup Profile. Expressions must return a string or a number and may access data values from the bin and its aggregated features with the $feature and $aggregatedFeatures profile variables.

See also

Arcade Feature Reduction Popup Profile

Examples

// enables binning on the layer with a
// popup describing the number of features represented by each bin
layer.featureReduction = {
  type: "binning",
  fields: [{
    name: "aggregateCount",
    statisticType: "count"
  }],
  popupTemplate: {
    content: "This bin contains <b>{aggregateCount}</b> features."
    fieldInfos: [{
      fieldName: "aggregateCount",
      format: {
        digitSeparator: true,
        places: 0
      }
    }]
  }
};

// enables binning on the layer with a
// popup describing the average value of
// the temperature field
layer.featureReduction = {
  type: "binning",
  fields: [{
    name: "avg_temperature",
    alias: "Average temperature",
    onStatisticField: "temperature",
    statisticType: "avg"
  }, {
    name: "aggregateCount",
    statisticType: "count"
  }],
  popupTemplate: {
    content: [{
      type: "text",
      text: "This bin contains <b>{aggregateCount}</b> features."
    }, {
      type: "text",
      text: "The average temperature in this bin is <b>{avg_temperature}° F</b>."
    }],
    fieldInfos: [{
      fieldName: "aggregateCount",
      format: {
        digitSeparator: true,
        places: 0
      }
    }, {
      fieldName: "avg_temperature",
      format: {
        places: 1
      }
    }]
  }
};

// Displays an ordered list of the top 5 categories
// of features contained within the bin
layer.popupTemplate = {
  title: "Power plant summary",
  content: [{
   type: "expression",
   // lists the top 5 most common fuel types in the bin
   expressionInfo: {
     expression: `
       Expects($aggregatedFeatures, "fuel1")

       var statsFS = GroupBy($aggregatedFeatures,
         [
           { name: 'Type', expression: 'fuel1'},
         ],
         [
           { name: 'num_features', expression: '1', statistic: 'COUNT' }
         ]
       );
       var ordered = Top(OrderBy(statsFs, 'num_features DESC'), 5);

       // create an HTML ordered list as a string and return in a rich text element
       var list = "<ol>";

       for (var group in ordered){
         list += \`<li>\${group.Type} (\${Text(group.num_features, "#,###")})</li>\`
       }
       list += "</ol>";

       return {
         type: "text",
         text: list
       }
     `,
     title: "List of fuel types"
   }
 }]
};

renderer Property renderer Rendererautocast

The renderer used to style the bins. Depending on the renderer type, features may be visualized with the same symbol or with varying symbols based on the values of the provided fields. Since bins are defined geometrically as polygons, only renderer and symbol types suited for polygon geometries are supported (e.g. HeatmapRenderer is not supported).

Any aggregate field defined in fields may be used by the renderer. Typically, binning visualizations use a field for aggregate count in a color visual variable to visualize the total count of features within each bin.

See also

Sample - Binning - basic configuration

Example

featureReduction.renderer = {
  type: "simple",  // autocasts as new SimpleRenderer()
  symbol: {
    type: "simple-fill",  // autocasts as new SimpleFillSymbol()
    outline: {  // autocasts as new SimpleLineSymbol()
      width: 0.5,
      color: "white"
    }
  },
  visualVariables: [{
    type: "color",
    field: "aggregateCount",
    stops: [
      { value: 1, color: "white" },
      { value: 1000, color: "blue" }
    ]
  }]
};

type Property type String

The feature reduction type.

For FeatureReductionBinning the type is always "binning".

Example

// enables binning on the layer
layer.featureReduction = {
  type: "binning"
};

Method Overview

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Return Type	Summary	Class
	Adds one or more handles which are to be tied to the lifecycle of the object.	Accessor
FeatureReductionBinning	Creates a deep clone of the FeatureReductionBinning object.	FeatureReductionBinning
*	Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product.	FeatureReductionBinning
Boolean	Returns true if a named group of handles exist.	Accessor
	Removes a group of handles owned by the object.	Accessor
Object	Converts an instance of this class to its ArcGIS portal JSON representation.	FeatureReductionBinning

Method Details

addHandles Inherited Method addHandles(handleOrHandles, groupKey) Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, addHandles added at 4.25.

Adds one or more handles which are to be tied to the lifecycle of the object. The handles will be removed when the object is destroyed.

// Manually manage handles
const handle = reactiveUtils.when(
  () => !view.updating,
  () => {
    wkidSelect.disabled = false;
  },
  { once: true }
);

this.addHandles(handle);

// Destroy the object
this.destroy();

Parameters

handleOrHandles WatchHandle|WatchHandle []

Handles marked for removal once the object is destroyed.

groupKey *

optional

Key identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group.

clone Method clone(){FeatureReductionBinning}

Creates a deep clone of the FeatureReductionBinning object.

Returns

Type	Description
FeatureReductionBinning	A deep clone of the object that invoked this method.

Example

// Creates a deep clone of the feature reduction object
const fr = layer.featureReduction.clone();
fr.fixedBinSize = 5;
layer.featureReduction = fr;

fromJSON Method fromJSON(json){*}static

Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product. The object passed into the input json parameter often comes from a response to a query operation in the REST API or a toJSON() method from another ArcGIS product. See the Using fromJSON() topic in the Guide for details and examples of when and how to use this function.

Parameter

json Object

A JSON representation of the instance in the ArcGIS format. See the ArcGIS REST API documentation for examples of the structure of various input JSON objects.

Returns

Type	Description
*	Returns a new instance of this class.

hasHandles Inherited Method hasHandles(groupKey){Boolean} Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 4.25.

Returns true if a named group of handles exist.

Parameter

groupKey *

optional

A group key.

Returns

Type	Description
Boolean	Returns `true` if a named group of handles exist.

Example

// Remove a named group of handles if they exist.
if (obj.hasHandles("watch-view-updates")) {
  obj.removeHandles("watch-view-updates");
}

removeHandles Inherited Method removeHandles(groupKey) Inherited from Accessor Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 4.25.

Removes a group of handles owned by the object.

Parameter

groupKey *

optional

A group key or an array or collection of group keys to remove.

Example

obj.removeHandles(); // removes handles from default group

obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");

toJSON Method toJSON(){Object}

Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() guide topic for more information.

Returns

Type	Description
Object	The ArcGIS portal JSON representation of an instance of this class.