Summarize Center and Dispersion

The Summarize Center and Dispersion task finds central features and directional distributions.

It can be used to answer questions such as:

• Where is the center?
• Which feature is the most accessible from all other features?
• How dispersed, compact, or integrated are the features?
• Are there directional trends?

Request URL

http://<analysis url>/SummarizeCenterAndDispersion/submitJob

Request Parameters

Parameter	Description
analysisLayer (Required)	The point, line, or polygon features to be analyzed. Syntax: As described in detail in the Feature input topic, this parameter can be one of the following: A URL to a feature service layer with an optional filter to select specific features A feature collection Examples: {"url": <feature service layer url>, "filter": <where clause>} {"layerDefinition": {}, "featureSet": {}, "filter": <where clause>}
summarizeType	The method with which to summarize the analysisLayer. Values: CentralFeature | MeanCenter | MedianCenter | Ellipse Example: " summarizeType": "CentralFeature"
ellipseSize	The size of the output ellipse in standard deviations. The default ellipse size is 1. Valid choices are 1, 2, or 3 standard deviations. Examples: "ellipseSize": "1 standard deviation" "ellipseSize": "2 standard deviations" "ellipseSize": "3 standard deviations"
weightField	A numeric field in the analysisLayer to be used to weight locations according to their relative importance. Example: "weightField": "NumEmployees"
groupField	The field used to group features for separate directional distribution calculations. The groupField can be of integer, date, or string type. Example: "groupField": "Country"
OutputName	If provided, the task will create a feature service of the results. You define the name of the service. If an outputName value is not provided, the task will return a feature collection. Syntax: { "serviceProperties": { "name": "<service name>" } } In ArcGIS Online or ArcGIS Enterprise 11.0 and later, you can overwrite an existing feature service by providing the itemId value of the existing feature service and setting the overwrite property to true. Including the serviceProperties parameter is optional. As described in the Feature output topic, you must either be the owner of the feature service or have administrative privileges to perform the overwrite. Syntax: { "itemProperties": { "itemId": "<itemID of the existing feature service>", "overwrite": true } } or { "serviceProperties": { "name": "<existing service name>" }, "itemProperties": { "itemId": "<itemID of the existing feature service>", "overwrite": true } }
Context	The Context parameter contains the following additional settings that affect task operation: Extent (extent)—A bounding box that defines the analysis area. Only input features that intersect the bounding box will be analyzed. Output spatial reference (outSR)—The output features will be projected into the output spatial reference. Syntax: { "extent" : {extent}, "outSR" : {spatial reference} }
f	The response format. The default response format is html. Values: html | json | kmz

Response

When you submit a request, the service assigns a unique job ID for the transaction.

Syntax:

{
"jobId": "<unique job identifier>",
"jobStatus": "<job status>"
}

After the initial request is submitted you can use the jobId to periodically check the status of the job and messages as described in the topic Checking job status. Once the job has successfully completed, you use the jobId to retrieve the results. To track the status, you can make a request of the following form:

http://<analysis url>/SummarizeCenterAndDispersion/jobs/<jobId>

Accessing results

When the status of the job request is esriJobSucceded, you can access the results of the analysis by making a request of the following form.

http://<analysis url>/SummarizeCenterAndDispersion/jobs/<jobId>/results/centralFeatureResultLayer?token=<your token>&f=json

Parameter

Description

centralFeatureResultLayer meanCenterResultLayer medianCenterResultLayer ellipseResultLayer

The output result. Example: {"url": "http://analysis.arcgis.com/arcgis/rest/services/tasks/gpserver/summarizecenteranddistribution/jobs/<jobId>/results/ellipseResultLayer"} The result has properties for parameter name, data type, and value. The contents of value depends upon the OutputName parameter provided in the initial request. If OutputName was provided, value contains the url to the feature service layer. { "paramName":"ellipseResultLayer", "dataType":"GPString", "value":{"url":"<arcgis featureservice layer url>"} } If OutputName was not provided, value contains a feature collection. { "paramName":"ellipseResultLayer", "dataType":"GPString", "value":{"featureCollection": ... } } See Feature Output for more information about how the result layer or collection is accessed.