require(["esri/rest/support/StatisticDefinition"], (StatisticDefinition) => { /* code goes here */ });
import StatisticDefinition from "@arcgis/core/rest/support/StatisticDefinition.js";
esri/rest/support/StatisticDefinition
This class defines the parameters for querying a layer or layer view for statistics.
- See also
// 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);
});
Constructors
-
Parameterproperties Objectoptional
See the properties for a list of all the properties that may be passed into the constructor.
Property Overview
Name | Type | Summary | Class |
---|---|---|---|
The name of the class. | Accessor | ||
Defines the field for which statistics will be calculated. | StatisticDefinition | ||
Specifies the output field name for the requested statistic. | StatisticDefinition | ||
The parameters for percentile statistics. | StatisticDefinition | ||
Defines the type of statistic. | StatisticDefinition |
Property Details
-
onStatisticField
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
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
statisticParameters Object
-
The parameters for percentile statistics. This property must be set when the statisticType is set to either
percentile-continuous
orpercentile-discrete
.- Properties
-
value Number
Percentile value. This should be a decimal value between 0 and 1.
orderBy StringSpecify
ASC
(ascending) orDESC
(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 withorderBy
set to ascending (ASC
) is 9, but whenorderBy
is set to descending (DESC
) the result is 2. The default isASC
.Possible Values:"ASC"|"DESC"
- Default Value:null
Exampleslet 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
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
exceptpercentile-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
orpercentile-discrete
statistics. - The
percentile-continuous
andpercentile-discrete
statistic types cannot be used with the having parameter. - The
percentile-continuous
andpercentile-discrete
statistic types are supported if capabilities.query.supportsPercentileStatistics istrue
. - The
envelope-aggregate
,centroid-aggregate
andconvex-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
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); } }); });
- The statisticParameters must be set when calculating
Method Overview
Name | Return Type | Summary | Class |
---|---|---|---|
Adds one or more handles which are to be tied to the lifecycle of the object. | Accessor | ||
Creates a deep clone of StatisticDefinition object. | StatisticDefinition | ||
* | Creates a new instance of this class and initializes it with values from a JSON object generated from an ArcGIS product. | StatisticDefinition | |
Returns true if a named group of handles exist. | Accessor | ||
Removes a group of handles owned by the object. | Accessor | ||
Converts an instance of this class to its ArcGIS portal JSON representation. | StatisticDefinition |
Method Details
-
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25Accessor 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();
ParametershandleOrHandles WatchHandle|WatchHandle[]Handles marked for removal once the object is destroyed.
groupKey *optionalKey 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
clone(){StatisticDefinition}
-
Creates a deep clone of StatisticDefinition object.
ReturnsType Description StatisticDefinition A new instance of a StatisticDefinition object equal to the object used to call .clone()
.
-
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.Parameterjson ObjectA 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.
ReturnsType Description * Returns a new instance of this class.
-
hasHandles
InheritedMethodhasHandles(groupKey){Boolean}
Inherited from AccessorSince: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, hasHandles added at 4.25. -
Returns true if a named group of handles exist.
ParametergroupKey *optionalA group key.
ReturnsType 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"); }
-
Inherited from Accessor
Since: ArcGIS Maps SDK for JavaScript 4.25Accessor since 4.0, removeHandles added at 4.25. -
Removes a group of handles owned by the object.
ParametergroupKey *optionalA group key or an array or collection of group keys to remove.
Exampleobj.removeHandles(); // removes handles from default group obj.removeHandles("handle-group"); obj.removeHandles("other-handle-group");
-
toJSON
toJSON(){Object}
-
Converts an instance of this class to its ArcGIS portal JSON representation. See the Using fromJSON() guide topic for more information.
ReturnsType Description Object The ArcGIS portal JSON representation of an instance of this class.