Perform a feature analysis

A feature analysis is the process of using the spatial analysis service to perform server-side geometric and analytic operations on feature data. All feature analysis requests are job requests. The easiest way to programmatically run an analysis request to the spatial analysis service is to use ArcGIS REST JS, which provides a Job class that handles long- running operations.

In this tutorial, you use ArcGIS REST JS to perform a hot spot analysis to find statistically significant clusters of parking violations.

Prerequisites

You need the following to access the spatial analysis service and perform feature analysis operations:

An ArcGIS Online account.
A registered application to obtain its Client ID.
The redirect URL of the registered application to use for authentication in the format "https://<server>[:port]" as in: https://localhost:8080.

Steps

Download the starter code

Download the tutorial starter code zip file from the portal.

The zip file contains the following:

feature-analysis.html
authenticate.html

The feature-analysis.html file contains basic HTML scaffolding and the OAuth 2.0 code necessary to perform the analysis. The authenticate.html file is the callback page used as part of the authentication process.

Configure authentication

To access the spatial analysis service, you need to have an ArcGIS Online account and sign in with user authentication, which creates a temporary token using OAuth 2.0 protocol. API keys are not supported.

Use the ArcGISIdentityManager class to configure user authentication. To learn more, go to the Authentication chapter.

Go to the item page of your OAuth credentials and copy the Client ID.

In the feature-analysis.html file, replace YOUR_CLIENT_ID with your Client ID.

Expand
Use dark colors for code blocks
      let session = null;
      let lastResultUrl = null;

      const clientId = 'YOUR_CLIENT_ID';


      const signInLabel = "Sign in";

      const modalText = "To perform feature analysis you need an ArcGIS Online account. Learn more in <a href='https://developers.arcgis.com/documentation/mapping-apis-and-services/spatial-analysis/feature-analysis/introduction/#limitations'>Limitations.</a>"
Expand

In the authenticate.html file, replace YOUR_CLIENT_ID with your Client ID.

Expand
Use dark colors for code blocks
    <script type="module">
      import { ArcGISIdentityManager } from 'https://esm.run/@esri/arcgis-rest-request@4';

      const clientId = "YOUR_CLIENT_ID";

      const redirectUri = "authenticate.html";
      ArcGISIdentityManager.completeOAuth2({
        clientId,
        redirectUri
      })
    </script>
Expand

Run the application and navigate to your localhost, for example https://localhost:8080.

You should be able to click the Sign in button and successfully log in to an ArcGIS Online account.

Get the analysis URL

To make a request to the spatial analysis service, you need to get the URL first. The analysis service URL is unique to your organization.

Call the getSelf operation from ArcGIS REST JS to obtain the analysis URL.

Expand
Use dark colors for code blocks
      const getAnalysisUrl = async (withAuth) => {
        const portalSelf = await getSelf({
          authentication: withAuth,
        });

        return portalSelf.helperServices.analysis.url;
      };


      document
        .getElementById('withPopupButton')
        .addEventListener('click', getAuth);
Expand

Make the request

Use the Job class and set the operationURL and params required for the selected analysis.

Create a function that submits a Job request to the spatial analysis service using your organization's analysis URL. Set the params required for a hot spot analysis and authenticate using the session token.

Expand
Use dark colors for code blocks
      const getAnalysisUrl = async (withAuth) => {
        const portalSelf = await getSelf({
          authentication: withAuth,
        });

        return portalSelf.helperServices.analysis.url;
      };

      const runAnalysis = async () => {
        const analysisUrl = await getAnalysisUrl(session);
        const operationUrl = `${analysisUrl}/FindHotSpots/submitJob`;
        const params = {
          analysisLayer: { url: points },
          shapeType: 'Hexagon',
          outputName: {
            serviceProperties: {
              name: `RestJS_find_hot_spots_${new Date().getTime()}`,
            },
          }, //Outputs results as a hosted feature serivce.
        };

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

        // 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();

        // jobResp.aggregatedLayer.value.url
        return jobResp;
      };
Expand

Call the runAnalysis function to run the operation.

Expand
Use dark colors for code blocks
        const clearResults = () => {
            document.getElementById('clearResultsBtn').disabled = true;
            document.getElementById('runAnalysisBtn').disabled = false;
            document.getElementById('resultsCBox').checked = false;
        };

      const runAnalysisBtnWasClicked = (evt) => {
        document.getElementById('runAnalysisBtn').hidden = true;
        document.getElementById('progressBar').hidden = false;
        document.getElementById('withPopupButton').disabled = true;

        runAnalysis().then(
          (results) => {
            document.getElementById('runAnalysisBtn').hidden = false;
            document.getElementById('progressBar').hidden = true;
            document.getElementById('withPopupButton').disabled = false;

          },
          (err) => {
            console.log(err);
            document.getElementById('progressBar').hidden = true;
            document.getElementById('runAnalysisBtn').hidden = false;
            document.getElementById('withPopupButton').disabled = false;
            showAlert(err);
          }
        );

      };
Expand

Handle the results

The results of a feature analysis are returned as feature data.

Access the URL of the resulting hosted feature layer.

Expand
Use dark colors for code blocks
        const getResults = () => {
        // You can use this URL to display the results on a map with ArcGIS API for JavaScript or an open source mapping API.
        console.log(lastResultUrl)
        document.getElementById('clearResultsBtn').disabled = false;
        document.getElementById('runAnalysisBtn').disabled = true;
        };

        const clearResults = () => {
            document.getElementById('clearResultsBtn').disabled = true;
            document.getElementById('runAnalysisBtn').disabled = false;
            document.getElementById('resultsCBox').checked = false;
        };

      const runAnalysisBtnWasClicked = (evt) => {
        document.getElementById('runAnalysisBtn').hidden = true;
        document.getElementById('progressBar').hidden = false;
        document.getElementById('withPopupButton').disabled = true;

        runAnalysis().then(
          (results) => {
            document.getElementById('runAnalysisBtn').hidden = false;
            document.getElementById('progressBar').hidden = true;
            document.getElementById('withPopupButton').disabled = false;

            lastResultUrl = results.hotSpotsResultLayer.value.url;
            getResults();

          },
          (err) => {
            console.log(err);
            document.getElementById('progressBar').hidden = true;
            document.getElementById('runAnalysisBtn').hidden = false;
            document.getElementById('withPopupButton').disabled = false;
            showAlert(err);
          }
        );

      };
Expand

Run the app

Run the application and navigate to your localhost, for example: https://localhost:8080.

When you click Run analysis button, you submit a request to the spatial analysis service to perform a hot spot analysis. When the job is complete, you can use the URL of the resulting feature layer in the app. The metadata of the layer will look something like this:

Use dark colors for code blocks

Copy

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
{
  "currentVersion": 11,
  "id": 0,
  "name": "HotSpotsLayer",
  "type": "Feature Layer",
  "serviceItemId": "898aacb4ea5c4b00b4a51c634f268459",
  "cacheMaxAge": 30,
  "displayField": "",
  "description": "",
  "copyrightText": "",
  "defaultVisibility": true,
  "editingInfo": {
    "lastEditDate": 1667488958822,
    "schemaLastEditDate": 1667488958822,
    "dataLastEditDate": 1667488958822
  },
  "relationships": [],
  "isDataVersioned": false,
  "hasContingentValuesDefinition": false,
  "supportsAppend": true,
  "supportsCalculate": true,
  "supportsASyncCalculate": true,
  "supportsTruncate": true,
  "supportsAttachmentsByUploadId": true,
  "supportsAttachmentsResizing": true,
  "supportsRollbackOnFailureParameter": true,
  "supportsStatistics": true,
  "supportsExceedsLimitStatistics": true,
  "supportsAdvancedQueries": true,
  "supportsValidateSql": true,