Tutorial: Perform an analysis with raster functions

Create a raster function template

1. In a web browser, Sign in to your portal with your ArcGIS account.

2. On the main menu, click Content. Then click the New Item button.

3. In the New item dialog select Raster function template.

4. Fill out the following fields:

   • Title: Santa Monica - Terrain ruggedness index
   • Tags: raster, analysis, function, template, santa monica, tutorial
   • Summary: The Terrain Ruggedness Index (TRI) is used to express the amount of elevation difference between adjacent cells of a DEM.

5. Click Save, then click Yes in the popup to open the template item in the Raster Function Editor.

6. You will be presented with a blank function template diagram in the Raster Function Editor tool window.

   

An new item is created in your portal.

Add raster functions

1. In the Raster Function Editor, from the tools in the top right corner, click Add Raster Variable.

2. Search for the built in Extract Bands function in the left side bar, and click the Add Function Button. The Extract Bands function will be added to your diagram.

3. To connect the variable as input to the Extract Bands function. Drag a line from the Raster Variable to the new Extract Bands function.

4. Double click the Extract Bands function to open the function properties dialog. Click through each of the tabs and fill out the properties to match below:

   

5. Add the Calculator function to your diagram and connect the output of the Extract Bands function as an input to the Calculator function.

6. Open the properties of the Calculator function, Click the parameters tab and enter the following values:

   • Raster Variables : DEM
   • Expression: SquareRoot(Abs((Square(Focal_Max(DEM,3,3)) - Square(Focal_Min(DEM,3,3)))))
   • CellSize Type: Min Of
   • Extent Type: First Of
   

7. Add the Remap function to your diagram and connect the output of the Calculator function as an input to the Remap function.

8. Open the properties of the Remap function, Click the parameters tab and enter the following values:

   ID	Minimum	Maximum	Output
   1	0	80	1
   2	81	116	2
   3	117	161	3
   4	162	239	4
   5	240	497	5
   6	498	958	6
   7	959	5000	7

   

9. Add the Attribute Table function to the diagram and connect the output of the Remap Function as the input to the Attribute Table function.

10. Open the properties of the Attribute Table function, click the parameters tab and enter the following values:

    • Table Type: Manual

      ID	Value	ClassName	Color
      1	1	Level	#3AA900
      2	2	Nearly Level	#6EC500
      3	3	Slightly Rugged	#B2E300
      4	4	Intermediately Rugged	#FFFC00
      5	5	Moderately Rugged	#FFAA00
      6	6	Highly Rugged	#FF5200
      7	7	Extremely Rugged	#ff0100

    

11. You completed raster function template should should look like this:

    

12. Click the Save button to persist your edits and close the Raster Function Editor tool.

Perform the analysis

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# send the request
output_result = generate_raster(
    raster_function=rft_json,
    function_arguments={"Raster": {"url": dem.url}},
    output_name="Santa Monica TRI (python)",
    context={
        "extent": {
            "xmin": -13203076.3188,
            "ymin": 4035131.0044,
            "xmax": -13193005.7403,
            "ymax": 4043863.9349,
            "spatialReference": {"wkid": 102100, "latestWkid": 3857},
        }
    },
)

# handle the output
print(f"output item id: {output_result.itemid}")

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

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POST {YOUR_RASTER_ANALYSIS_SERVICE_URL}/GenerateRaster/submitJob HTTP/1.1
Content-Type: application/x-www-form-urlencoded

f=json
&functionArguments='{"Raster": {"url":"https://tiledimageservices3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Santa_Monica_terrain_10m/ImageServer"}}'
&rasterFunction={RASTER_FUNCTION_TEMPLATE_DATA}
&outputName='{"serviceProperties":{"name":"Santa Monica ri postman","capabilities":"Image, TilesOnly"},"itemProperties":{"description":"Output generated from running Terrain ruggedness index raster function","snippet":"Output generated from running Terrain ruggedness index raster function","folderId":""}}'
&context='{"extent":{"xmin":-13203076.318831703,"ymin":4035131.004497903,"xmax":-13193005.740355143,"ymax":4043863.934979473,"spatialReference":{"wkid":102100,"latestWkid":3857}}}'
&token={ACCESS_TOKEN}

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{
  "jobId": "{JOB_ID}",
  "jobStatus": "esriJobNew"
}

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POST {YOUR_RASTER_ANALYSIS_SERVICE_URL}/GenerateRaster/jobs/{JOB_ID} HTTP/1.1
Content-Type: application/x-www-form-urlencoded

f=json
&token={ACCESS_TOKEN}

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{
  "jobId": "{JOB_ID}",
  "jobStatus": "esriJobSucceeded",
  "inputs": {
    "rasterFunction": {
      "paramUrl": "inputs/rasterFunction"
    },
    "outputName": {
      "paramUrl": "inputs/outputName"
    },
    "context": {
      "paramUrl": "inputs/context"
    }
  },
  "results": {
    "outputRaster": {
      "paramUrl": "results/outputRaster"
    }
  }
}

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POST {YOUR_RASTER_ANALYSIS_SERVICE_URL}/GenerateRaster/jobs/{JOB_ID}/results/outputRaster HTTP/1.1
Content-Type: application/x-www-form-urlencoded

f=json
&token={ACCESS_TOKEN}

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{
  "paramName": "outputRaster",
  "dataType": "GPString",
  "value": {
    "itemId": "aea4a55621f040c6960ab089d1168398",
    "url": "https://tiledimageservices3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Santa Monica TRI/ImageServer"
  }
}