Calculate composite index | Documentation

A composite index analysis resulting in a new layer with the calculated index of influenza risk.

What is a composite index analysis

A composite index analysis combines multiple variables into a single score by standardizing, weighting, and classifying the result for decision-making. It uses numeric fields from feature dataFeature data is a general term for one or more features, which are records that represent real-world geographic entities, stored as a feature collection, feature layer, or hosted feature layer.Learn more, and returns a new feature serviceA feature service is a data service that provides access to spatial and non-spatial data in feature layers, feature layer views, and tables.Learn more as an asynchronous job. Use the spatial analysis serviceA spatial analysis service, also known as a feature analysis service, is a service used to perform spatial analysis operations on feature data such as finding, comparing, summarizing, analyzing patterns, and calculating geometries.Learn more and the CalculateCompositeIndex operation to run it.

Real-world examples of this analysis include the following:

Map heat vulnerability to prioritize cooling and greening investments.
Rank watershed stress to target restoration efforts.
Identify transit equity gaps to guide service improvements.
Prioritize flood-risk areas for mitigation and infrastructure funding.

To learn more, go to the Creating Composite Indices technical paper.

How a composite index analysis works

The general steps to performing a composite index analysis are as follows:

Review the parameters for the CalculateCompositeIndex operation.
Send a request to get the spatial analysis service URL.
Execute a job request with the following URL and parameters:
- URL: https://<YOUR_ANALYSIS_SERVICE>/arcgis/rest/services/tasks/GPServer/CalculateCompositeIndex/submitJob
- Parameters:
  - inputLayer: The features containing the variables that will be combined into the index.
  - inputVariables: The fields that will be combined to create the index.
  - outputName: A string representing the name of the hosted feature layer to return with the results.
Check the status.
Get the output layer results.

To see examples using ArcGIS API for Python, ArcGIS REST JS, and the ArcGIS REST API, go to Examples below.

URL Request

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http://<YOUR_ANALYSIS_SERVICE>/arcgis/rest/services/tasks/GPServer/CalculateCompositeIndex/submitJob?<parameters>

Required parameters

Name	Description	Examples
`f`	The format of the data returned.	`f=json` `f=pjson`
`token`	An access tokenAn access token is an authorization string that provides access to secure ArcGIS content, data, and services. Its capabilities are determined by the privileges it supports. It is obtained by implementing API key authentication, User authentication, or App authentication.Learn more from user authentication, API key, or app authentication. The access token requires account impersonation. To learn more see Security and authentication guide > Privileges.	`token=<ACCESS_TOKEN>`
`inputLayer`	The input features containing the variables that will be combined into the index	`{"url": <SERVICE_URL>, "filter": <where clause>}` `{"layerDefinition": {}, "featureSet": {}, "filter": <where clause>}`
`inputVariables`	The fields that will be combined to create the index.	`"inputVariables": [ {"field":"<FIELD_NAME_1>","reverseVariable":true,"weight":2}, {"field":"<FIELD_NAME_2>","reverseVariable":false,"weight":1}, {"field":"<FIELD_NAME_3>","reverseVariable":false,"weight":1} ]`

Key parameters

Name	Description	Examples
`indexMethod`	The methods that will be used to scale the inputVariables parameter.	"meanScaled" \| "meanPercentile" \| "meanRow" \| "geomeanScaled" \| "geomeanPercentile" \| "geomeanRow" \| "sumFlags" \| "Percentile"
`outputIndexReverse`	A Boolean value that specifies whether the output index should be reversed.	"outputIndexReverse": true

Examples

Calculate influenza risk

In this example, the CalculateCompositeIndex is used to combine multiple variables into a single score for influenza risk.

In this analysis, the following variables are used to calculate influenza risk:

The percentage of the population that is over 65 years old, which is a high-risk group for influenza.
The percentage of the population that reports being in poor or fair health, which can increase susceptibility to influenza.
The percentage of the population that has received the influenza vaccine, which can reduce the risk of infection.

A composite index analysis resulting in a new layer with the calculated index of influenza risk.

APIs

ArcGIS API for Python

ArcGIS REST JS

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input_layer_url = "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Minnesota_county_health_rankings/FeatureServer/0"

results = calculate_composite_index(
    input_layer=input_layer_url,
    input_variables=[
        {"reverseVariable":False,"weight":1,"field":"v053_rawvalue"},
        {"reverseVariable":False,"weight":1,"field":"v002_rawvalue"},
        {"reverseVariable":True,"weight":1,"field":"v155_rawvalue"}
    ],
    index_method="meanScaled",
    output_index_reverse=False,
    # Outputs results as a hosted feature layer.
    output_name="Calculate composite index python results",
)

result_features = results.layers[0].query()

print(f"The index result layer has {len(result_features.features)} new records")

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Go to API Reference

Service requests

Request

HTTP

cURL

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POST arcgis.com/sharing/rest/portals/self HTTP/1.1
Content-Type: application/x-www-form-urlencoded

&f=json
&token=<ACCESS_TOKEN>
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Response (JSON)

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{
  "helperServices": {
    // Other parameters...
    "analysis": {
      "url": "https://{YOUR_ANALYSIS_SERVICE}/arcgis/rest/services/tasks/GPServer"
    }
  }
}

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Request

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cURL

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POST <YOUR_ANALYSIS_SERVICE>/CalculateCompositeIndex/submitJob HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Authorization: <YOUR_ACCESS_TOKEN>

&f=json
&inputLayer={"url": "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Minnesota_county_health_rankings/FeatureServer/0"}
&inputVariables=[{"reverseVariable":false,"weight":1,"field":"v053_rawvalue"},{"reverseVariable":false,"weight":1,"field":"v002_rawvalue"},{"reverseVariable":true,"weight":1,"field":"v155_rawvalue"}]
&indexMethod=meanScaled
&outputIndexReverse=false
&outputName={"serviceProperties":{"name":"Calculate composite index results"}}

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Response (JSON)

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{
  "jobId": "<JOB_ID>",
  "jobStatus": "esriJobSubmitted",
  "results": {},
  "inputs": {},
  "messages": []
}

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POST <YOUR_ANALYSIS_SERVICE>/CalculateCompositeIndex/jobs/<JOB_ID> HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Authorization: <YOUR_ACCESS_TOKEN>

&f=json

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Response (JSON)

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// Executing job
{
  "jobId": "<JOB_ID>",
  "jobStatus": "esriJobExecuting",
  "results": {},
  "inputs": {},
  "messages": []
}
// Job succeeded
{
    "jobId": "<JOB_ID>",
    "jobStatus": "esriJobSucceeded",
    "results": {
        "indexResultLayer": {
            "paramUrl": "results/indexResultLayer"
        },
        "processInfo": {
            "paramUrl": "results/processInfo"
        }
    },
    "inputs": {},
    "messages": [
        {
            "type": "esriJobMessageTypeWarning",
            "description": "{\"cost\": 0.087}"
        }
    ]
}

Request

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cURL

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POST <YOUR_ANALYSIS_SERVICE>/CalculateCompositeIndex/jobs/<JOB_ID>/results/indexResultLayer HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Authorization: <YOUR_ACCESS_TOKEN>

&f=json

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Response (JSON)

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{
  "paramName": "indexResultLayer",
  "dataType": "GPString",
  "value": {
      "url": "<RESULT_SERVICE_URL>"
  }
}