How to perform feature analysis

1. Prepare feature data

The preliminary step for most feature analyses is to prepare input feature data. The input data is the data that is analyzed during the operation. In most cases, you will want to perform an analysis with your own data, but you can also use existing data hosted in ArcGIS.

There are a number of ways you can prepare data for analysis, but the easiest way is to use ArcGIS software and tools such as ArcGIS Online, Map Viewer, and ArcGIS Pro. These tools provide an interactive way to find, import, and prepare data.

Regardless of the tools or APIs you use, the analysis service requires input data in the form of feature data. The feature data must be a collection of features where each feature has a geometry and a set of attributes. The geometry type and attribute fields must be the same for all features. The format of the feature data can be a hosted feature layer (URL) or a feature collection (JSON).

The input data for an analysis is not changed by the analysis service and is treated as read-only. The output data contains changes that were applied during the analysis.

How to prepare data

2. Select an operation

You can perform many different types of analyses with the feature analysis service. The operation you use depends on the type of data you have and the problem you want to solve. Use the table of categories below to help choose the correct operation. For more details about each, go to Types of feature analysis.

Category	Description	Operations	Result	Example
Find data	Selects a subset of features using a SQL or spatial query.	FindExistingLocations, DeriveNewLocations, ExtractFeatures	A new feature collection or hosted feature layer.	Finds existing polygons that match a SQL query.
Combine data	Combines or joins features from two or more feature datasets.	Merge, Overlay, Join, Dissolve	A new feature collection or hosted feature layer.	Dissolves polygons from two input feature datasets.
Summarize data	Aggregates or summarizes feature data and creates statistics.	Aggregate points, Summarize nearby, Summarize within, Summarize center and dispersion	A new feature collection or hosted feature layer.	Aggregate points into polygons.
Analyze patterns	Identifies spatial patterns and relationships in feature data.	Find hot spots, Find outliers, Find point clusters, Find similar locations, Calculate density, Interpolate points	A new feature collection or hosted feature layer.	Find hot spots based on attribute values
Calculate geometries	Performs geometric calculations on existing features or can create new feature data.	Create buffers, Create centroids, Generate tessellations,	A new feature collection or hosted feature layer.	Generate and merge buffers around features.

3. Perform the analysis

ArcGIS tools and APIs for analysis

To perform feature analysis, you can use different ArcGIS software and tools and APIs. In many cases, it is helpful to start by using tools to perform analyses interactively. Using tools will help you learn about the different types of operations, the required parameters, and how changing the parameters affects the analysis and results.

Below is a list of the different tools and APIs you can use:

1. ArcGIS software and tools: These are applications such as Map Viewer or ArcGIS Pro that you can use to perform analysis interactively, to experiment with different analyses and parameters, and to visualize the results. If you are new to ArcGIS, it is recommended to start with these tools. For documentation and tutorials, go to ArcGIS Online analysis and ArcGIS Pro Analytics.

2. ArcGIS APIs: These are programming APIs such as ArcGIS API for Python or ArcGIS REST JS that you can use to access the spatial analysis service. Use these APIs to build custom applications.

3. ArcGIS REST API: This is the API you use to directly access the spatial analysis service. Use the REST API to build custom applications that access the service with HTTP requests.

You can use different ArcGIS tools and APIs to perform a feature analysis. Regardless of the mechanism you use, they all require user authentication to make requests to the spatial analysis service and the transactions need to managed as job requests (long transactions).

Security and authentication

To access the spatial analysis service, you need to implement user authentication. If you are using applications such as the Map Viewer or ArcGIS Pro, they authenticate users when they sign in, and then make requests to the service with the user credentials when spatial analysis tools are used. If you are accessing the service programmatically, you need to implement a user authentication workflow. This typically involves using account credentials to get an access token and then making requests to the service. Learn more about user authentication and tokens in Security and authentication.

Job processing

All feature analysis requests to the spatial analysis service are job requests. Regardless of the tool or API you use, each analysis is a long transaction that needs to be executed, checked, and the results need to be retrieved by the application. Tools such as Map Viewer and ArcGIS Pro manage most of the transactions for you, but when using APIs you have to manage the transaction yourself. Learn about the steps required in the code examples below.

ArcGIS software and tools

You can use the Map Viewer and ArcGIS Pro to perform feature analysis interactively. The Map Viewer is a web application that allows you to perform mapping operations and execute different types of analyses. ArcGIS Pro is a desktop application that runs on Windows devices that you can also use to execute different types of analyses. Both applications store the results of an analysis in ArcGIS as a hosted feature layer and display the results after an analysis. They also make it easy to visually analyze and inspect the results of the analysis interactively.

ArcGIS APIs

The easiest way to programmatically execute an analysis request to the spatial analysis service is to use the ArcGIS API for Python or the ArcGIS REST JS API. These APIs provide security and authentication classes and also simplify the process of executing and managing job requests.

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traffic_crashes = "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Traffic_Crashes/FeatureServer/0"
fishnet = "fishnet"

results = find_hot_spots(
    analysis_layer=traffic_crashes,
    shape_type=fishnet,
    # Outputs results as a hosted feature layer.
    output_name="Hot spot analysis results",
)

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

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

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  const operationUrl = `${analysisUrl}/FindHotSpots/submitJob`;

  const params = {

    analysisLayer: {
      url:
        "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Traffic_Crashes/FeatureServer/0",
    },
    shapeType: "Fishnet",
    outputName: {
      serviceProperties: {
        name: "Hot spot analysis results", //Outputs results as a hosted feature serivce.
      },
    },

  };

  const jobReq = await Job.submitJob({
    url: operationUrl,
    params: params,
    authentication: auth,
  });

  //Listen to the status event to get updates every time the job status is checked.
  jobReq.on(JOB_STATUSES.Status, jobInfo => {
    console.log(jobInfo.status);
  });

  //Get all the results, this will start monitoring and trigger events
  const jobResp = await jobReq.getAllResults();

  console.log(jobResp);

ArcGIS REST API

To access the spatial analysis service directly, you need to get the URL from your organization and then execute a job request. You get the service URL by making a self request and then extracting the URL from helperServices. Once you have the URL you can execute a job request to perform the analysis.

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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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{
  "helperServices": {
    // Other parameters
    "analysis": {
      "url": "https://<YOUR_ANALYSIS_SERVICE>/arcgis/rest/services/tasks/GPServer"
    },
    "geoenrichment": {
      "url": "https://geoenrich.arcgis.com/arcgis/rest/services/World/GeoenrichmentServer"
    }
  }
}

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POST <YOUR_ANALYSIS_SERVICE>/arcgis/rest/services/tasks/GPServer/FindHotSpots/submitJob HTTP/1.1
Content-Type: application/x-www-form-urlencoded

&f=json
&token=<ACCESS_TOKEN>
&analysisLayer={"url":"https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Traffic_Crashes/FeatureServer/0"}
&shapeType=fishnet
&returnProcessInfo=true
&outputName={"serviceProperties":{"name":"Find hot spot results"}}
&context={}

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

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POST <YOUR_ANALYSIS_SERVICE>/arcgis/rest/services/tasks/GPServer/FindHotSpots/jobs/<JOB_ID> HTTP/1.1
Content-Type: application/x-www-form-urlencoded

&f=json
&token=<ACCESS_TOKEN>

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// Executing job
{
  "jobId": "<JOB_ID>",
  "jobStatus": "esriJobExecuting",
  "results": {},
  "inputs": {},
  "messages": []
}
// Job succeeded
{
  "jobId": "<JOB_ID>",
  "jobStatus": "esriJobSucceeded",
  "results": {
      "hotSpotsResultLayer": {
          "paramUrl": "results/hotSpotsResultLayer"
      },
      "processInfo": {
          "paramUrl": "results/processInfo"
      }
  },
  "inputs": {},
  "messages": []
}

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POST <YOUR_ANALYSIS_SERVICE>/arcgis/rest/services/tasks/GPServer/FindHotSpots/jobs/<JOB_ID>/results/hotSpotsResultLayer HTTP/1.1
Content-Type: application/x-www-form-urlencoded

&f=json
&returnType=data
&token=<ACCESS_TOKEN>

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{
  "paramName": "hotSpotsResultLayer",
  "dataType": "GPString",
  "value": {
      "url": "<SERVICE_URL>",
      "itemId": "<ITEM_ID>"
  }
}

4. Display the results

After you perform an analysis, the most common step is to display the results in a map. The spatial analysis service returns styling information with the resulting hosted feature layer and feature collection (JSON), so client applications and APIs can easily display the results in a map.

Visualize the layer

If you are using the Map Viewer or ArcGIS Pro, the resulting hosted feature layer is automatically added to the map when an analysis is complete. A renderer is also automatically applied from the styling information so you can visualize the results.

If you are using ArcGIS APIs, most APIs will access the styling information automatically in the resulting hosted feature layer to draw the feature layer in a map. The APIs access the styling information stored in the Drawing Info field of the feature layer.

If you own the resulting feature layer from analyses, you can use the item page, Map Viewer, or ArcGIS Pro to override drawing information by saving new colors and symbols in the layer. Alternatively, you can override the colors and symbols on the client-side using an ArcGIS API.

To learn more about visualizing data, go to Visualization.

Access the hosted feature layer

The easiest way to display the results of an analysis is to get the URL for the hosted feature layer that is returned and then use the URL to add the layer to the map. ArcGIS applications and APIs will use the URL to access the feature data and drawing information to render the layer in the map.

To learn more about accessing feature layers, go to Data hosting.

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    const analysisResultsLayer = new FeatureLayer({
      url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Traffic_Crashes_Resulting_in_Injury_Hot_Spots/FeatureServer/0"
    });

    const map = new Map({
      basemap: "arcgis/light-gray",
      layers: [analysisResultsLayer]
    });

    const view = new MapView({
      container: "viewDiv",
      map: map,
      center: [-122.440, 37.775],
      zoom: 12,
      constraints: {
        snapToZoom: false
      },
    });