StatisticDefinition

// query for the sum of the population in all features
let sumPopulation = {
  onStatisticField: "POP_2015",  // service field for 2015 population
  outStatisticFieldName: "Pop_2015_sum",
  statisticType: "sum"
}
let query = layer.createQuery();
query.outStatistics = [ sumPopulation ];
layer.queryFeatures(query)
  .then(function(response){
     let stats = response.features[0].attributes;
     console.log("output stats:", stats);
  });

// query for the average of the population change for all features
let populationChangeDefinition = {
  onStatisticField: "POP_2015 - POP_2010",  // service field for 2015 population
  outStatisticFieldName: "avg_pop_change_2015_2010",
  statisticType: "avg"
}
let query = layer.createQuery();
query.outStatistics = [ populationChangeDefinition ];
layer.queryFeatures(query)
  .then(function(response){
     let stats = response.features[0].attributes;
     console.log("Average change:", stats.avg_pop_change_2015_2010);
  });

Property Overview

Property Details

declaredClass Stringreadonly inherited

Since: ArcGIS Maps SDK for JavaScript 4.7

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

onStatisticField String

Defines the field for which statistics will be calculated. This can be service field names or SQL expressions. See the snippets below for examples.

Examples

// query for the sum of the population in all features
let sumPopulation = {
  onStatisticField: "POP_2015",  // service field for 2015 population
  outStatisticFieldName: "Pop_2015_sum",
  statisticType: "sum"
}
let query = layer.createQuery();
query.outStatistics = [ sumPopulation ];
layer.queryFeatures(query)
  .then(function(response){
     let stats = response.features[0].attributes;
     console.log("output stats:", stats);
  });

// query for the average of the population change for all features
// Notice that you can pass a SQL expression as a field name to calculate statistics
let populationChangeDefinition = {
  onStatisticField: "POP_2015 - POP_2010",  // service field for 2015 population
  outStatisticFieldName: "avg_pop_change_2015_2010",
  statisticType: "avg"
}
let query = layer.createQuery();
query.outStatistics = [ populationChangeDefinition ];
layer.queryFeatures(query)
  .then(function(response){
     let stats = response.features[0].attributes;
     console.log("Average change:", stats.avg_pop_change_2015_2010);
  });

// query for the average of the population change grouped by regions
// query result will also return an extent for each group encompassing
// all features in each group.
let populationChangeDefinition = {
  onStatisticField: "POP_2015 - POP_2010",  // service field for 2015 population
  outStatisticFieldName: "avg_pop_change_2015_2010",
  statisticType: "avg"
};
let aggregatedExtent = {
  statisticType: "envelope-aggregate"
};
let query = layer.createQuery();
query.groupByFieldsForStatistics = ["Region"];
query.outStatistics = [ populationChangeDefinition, aggregatedExtent ];
layer.queryFeatures(query).then(displayResults);

outStatisticFieldName String

Specifies the output field name for the requested statistic. Output field names can only contain alpha-numeric characters and an underscore. If no output field name is specified, the server assigns a field name to the returned statistic field.

statisticParameters Object

The parameters for percentile statistics. This property must be set when the statisticType is set to either percentile-continuous or percentile-discrete.

Properties

value Number Percentile value. This should be a decimal value between 0 and 1.

orderBy String optional Specify ASC (ascending) or DESC (descending) to control the order of the data. For example, in a data set of 10 values from 1 to 10, the percentile value for 0.9 with orderBy set to ascending (ASC) is 9, but when orderBy is set to descending (DESC) the result is 2. The default is ASC. Possible Values:"ASC"|"DESC"

Default Value:null

Examples

let query = layer.createQuery();
// find the median value in descending order for response_rate field
// for all features stored in the layer and order
query.outStatistics = [{
  statisticType: "percentile-continuous",
  statisticParameters: {
    value: 0.5,
    orderBy: "DESC"
  },
  onStatisticField: "response_rate",
  outStatisticFieldName: "Resp_rate_median"
}];
// query the features for the median value statistics against the values
// stored in the response_rate field
queryFeatures(query);

// Query the percentile for response time in descending order for all features in the layer
// group the percentile by Division and unit fields
let query = layer.createQuery();
query.orderByFields = ["Division, Unit"];
query.groupByFieldsForStatistics = ["Division, Unit"];
query.outStatistics = [{
  statisticType: "percentile-discrete",
  statisticParameters: {
    value: 0.67,
    orderBy: "DESC"
  },
  onStatisticField: "response_time",
  outStatisticFieldName: "response_time_percentile"
}];
queryFeatures(query);

statisticType String

Defines the type of statistic.

Possible Values

Value	Description
count	The number of features that match a specified criteria.
sum	The total sum of values that match a specified criteria.
min	The minimum value of a given field.
max	The maximum value of a given field.
avg	The average of values that match a specified criteria.
stddev	The standard deviation of values that match a specified criteria.
var	The statistical variance of values in the specified criteria.
percentile-continuous	An interpolated value above or below which a given percentage of values in a group of data lie. For example, the 90th percentile (value 0.9) is the value below which 90% of the data values may be found. percentile-continuous returns an interpolated value from the dataset.
percentile-discrete	Similar to percentile-continuous except percentile-discrete returns a data value from a dataset.
envelope-aggregate	Returns the spatial extent of grouped features when groupByFieldsForStatistics is used. Each statistics group will have an extent representing the bounding box of all features in that group.
centroid-aggregate	Returns the centroid of the grouped features when groupByFieldsForStatistics is used. Each statistics group will have a centroid representing the spatial center of features belonging to the group.
convex-hull-aggregate	Returns the convex hull of grouped features when groupByFieldsForStatistics is used. Each statistics group will have a convex hull representing the smallest area containing all features in that group.

Known Limitations

• The statisticParameters must be set when calculating percentile-continuous or percentile-discrete statistics.
• The percentile-continuous and percentile-discrete statistic types cannot be used with the having parameter.
• The percentile-continuous and percentile-discrete statistic types are supported if capabilities.query.supportsPercentileStatistics is true.
• The envelope-aggregate, centroid-aggregate and convex-hull-aggregate statistic types are not supported with ArcGIS Enterprise hosted and non-hosted feature services.

Possible Values:"count"|"sum"|"min"|"max"|"avg"|"stddev"|"var"|"percentile-continuous"|"percentile-discrete"|"envelope-aggregate"|"centroid-aggregate"|"convex-hull-aggregate"

See also

• Graphic.aggregateGeometries

Example

// average of age fields by regions
const ageStatsByRegion = new StatisticDefinition({
  onStatisticField: field,
  outStatisticFieldName: "avgAge",
  statisticType: "avg"
});

// extent encompassing all features by region
const aggregatedExtent = new StatisticDefinition({
  statisticType: "envelope-aggregate",
  outStatisticFieldName: "aggregateExtent",
});

// group the statistics by Region field
// get avg age by Regions and extent of each region
const query = layer.createQuery();
query.groupByFieldsForStatistics = ["Region"];
query.outStatistics = [consumeStatsByRegion, aggregatedExtent];
layer.queryFeatures(query).then((results) => {
  results.features.forEach((feature) => {
    if (feature.attributes.Region === "Midwest") {
       view.goTo(feature.aggregateGeometries.aggregateExtent);
    }
  });
});

Method Overview

Method Details

addHandles(handleOrHandles, groupKey)inherited

Since: ArcGIS Maps SDK for JavaScript 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(){StatisticDefinition}

Creates a deep clone of StatisticDefinition object.

Returns

Type	Description
StatisticDefinition	A new instance of a StatisticDefinition object equal to the object used to call .clone().

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(groupKey){Boolean}inherited

Since: ArcGIS Maps SDK for JavaScript 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(groupKey)inherited

Since: ArcGIS Maps SDK for JavaScript 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(){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.