summaryStatistics

AMD: require(["esri/smartMapping/statistics/summaryStatistics"], (summaryStatistics) => { /* code goes here */ });
ESM: import summaryStatistics from "@arcgis/core/smartMapping/statistics/summaryStatistics";
Function: esri/smartMapping/statistics/summaryStatistics
Since: ArcGIS API for JavaScript 4.2

Function for generating attribute statistics in a Layer based on values returned from a given field.

Known Limitations

  • SceneLayers must have the supportsRenderer and supportsLayerQuery capabilities enabled unless a predefined statistics object is provided to the statistics parameter of the method. To check a SceneLayer's capabilities, use the getFieldInfoUsage() method.
  • You cannot generate statistics using SQL expressions for client-side FeatureLayers in a SceneView.
  • The normalizationType parameter only normalizes data returned by a field. It does not apply to values returned from a valueExpression or sqlExpression.

Method Overview

Name Return Type Summary Function
Promise<SummaryStatisticsResult>more details

Returns an object containing statistics describing a set of values returned from a field (or expression) in a Layer.

more detailssummaryStatistics

Method Details

summaryStatistics(params){Promise<SummaryStatisticsResult>}

Returns an object containing statistics describing a set of values returned from a field (or expression) in a Layer.

Parameters:
Specification:
params Object

See the table below for details of each parameter.

Specification:

The layer from which to generate statistics for the given field.

field String
optional

The name of the numeric or string field for which the summary statistics will be generated. This property is ignored if a valueExpression is used.

valueExpression String
optional

An Arcade expression following the specification defined by the Arcade Visualization Profile. Expressions may reference field values using the $feature global variable and must return a number. This property overrides the field property and therefore is used instead of an input field value.

sqlExpression String
optional

A SQL expression evaluating to a number.

sqlWhere String
optional

A SQL where clause used to filter features for the statistics query. For example, this is useful in situations where you want to avoid dividing by zero as is the case with creating a predominance visualization.

normalizationType String
optional

Determines how the provided field values will be normalized. This parameter only normalizes data referenced by a field, and does not apply to values returned from a valueExpression or sqlExpression. See the table below for a list of possible values.

Possible Value Description
field Divides the data value using the value of the field specified in the normalizationField parameter. A normalizationField must be provided if this value is used.
percent-of-total Divides the data value by the sum of all data values then multiplies by 100. Use normalizationTotal to define the total value by which to normalize.
log Computes the base 10 logarithm of the data values. This can be a useful approach for viewing highly skewed data distributions because it reduces the influence of outliers. Only positive values are computed. You should avoid this normalization type if your data contains a significant number of negative values.
natural-log Computes the natural logarithm of the data values. This can be a useful approach for viewing highly skewed data distributions because it reduces the influence of outliers. Only positive values are computed. You should avoid this normalization type if your data contains a significant number of negative values.
square-root Computes the square root of the data values. This can be a useful approach for viewing highly skewed data distributions because it reduces the influence of outliers. Only positive values are computed. You should avoid this normalization type if your data contains a significant number of negative values.

Possible Values:"field"|"log"|"percent-of-total"|"natural-log"|"square-root"

normalizationField String
optional

The field by which to normalize the values returned from the given field.

normalizationTotal Number
optional

Only applies if normalizationType is percent-of-total. Indicates the total amount with which to normalize field values.

minValue Number
optional

The minimum bounding value for the statistics calculation. Use this in conjunction with maxValue to generate statistics between lower and upper bounds.

maxValue Number
optional

The maximum bounding value for the statistics calculation. Use this in conjunction with minValue to generate statistics between lower and upper bounds.

view View
optional

A SceneView or MapView instance is required when a valueExpression is specified.

features Graphic[]
Deprecated since version 4.23. Use useFeaturesInView instead.
optional

A subset of features for which to calculate the statistics.

useFeaturesInView Boolean
optional

Only applicable when the input layer is a service-backed FeatureLayer. When true, statistics will be calculated on the client from features visible in the view. If false, statistics will be requested from the service. Since version 4.23.

signal AbortSignal
optional

Allows for cancelable requests. If canceled, the promise will be rejected with an error named AbortError. See also AbortController.

Returns:
Type Description
Promise<SummaryStatisticsResult> Returns a promise that resolves to SummaryStatisticsResult.
Examples:
summaryStatistics({
  layer: featureLayer,
  valueExpression: "( ($feature.POP2020 - $feature.POP2010) / $feature.POP2010 ) * 100"
  view: mapView
}).then(function(stats){
  colorSlider.statistics = stats;
});
summaryStatistics({
  layer: featureLayer,
  field: "Population",
  normalizationType: "natural-log",
  sqlWhere: "Population > 0",
  numBins: 100
}).then(function(stats){
  histogramWidget.average = stats.avg;
});

Type Definitions

SummaryStatisticsResult

The statistics returned from the summaryStatistics() query.

Properties:
avg Number

The average of all values returned from the field or expression.

count Number

The total number of features with a non-null value for the given field.

max Number

The maximum of all values returned from the field or expression.

median Number

The median of all values returned from the field or expression. Since version 4.22.

min Number

The minimum of all values returned from the field or expression.

stddev Number

The standard deviation calculated from values returned from the field or expression.

sum Number

The sum of all values returned from the field or expression.

variance Number

The calculated variance from all values returned from the field or expression.

nullcount Number
optional

The number of null values stored in the given field. Only applies to summary statistics calculated with a field value at version 4.20 or later.

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