ArcGIS REST API

Create Viewshed

Description

Create Viewshed diagram

The Create Viewshed task uses an elevation surface and observer locations to identify areas where the observers can see the observed objects and the observed objects can see the observers.

Request parameters

The following table lists the parameters with syntax and details for each.

ParameterDetails
inputElevationSurface

(Required)

The input elevation surface for calculating the viewshed.

Syntax: This parameter can be specified as a Portal Item ID, a URL to a raster image service layer, a cloud raster dataset, or a shared raster dataset.

Examples:

//Input surface raster as portal item
"inputElevationSurface": {"itemId": <portal item id>}

//Input surface raster as URL
"inputElevationSurface": {"url": <image service layer url>}

inputObserverFeatures

(Required)

The input observer locations features.

Syntax: This parameter can be specified as one of the following: a URL to a feature service layer with an optional filter to select specific features, or a feature collection.

Input feature examples:

//Feature layer URL
"inputObserverFeatures": {"url": <feature service layer url>, "filter": <where clause>}

//Feature collection
"inputObserverFeatures": {"layerDefinition": {}, "featureSet", {}, "filter": <where clause>}

outputName

(Required)

The output image service name that will be created.

You can specify the name, or you can create an empty service using Portal Admin Sharing API and use the return JSON object as input to this parameter.

Syntax: A JSON object describes the name of the output or the output raster.

Output name example:

"outputName":{"serviceProperties":{"name":"testrasteranalysis"}}

Output raster examples:

//Output portal item:
"outputName":{"itemId": <portal item id>}

//Output url:
"outputName":{"url": <image service url}

//Output raster layer service:
"outputName":{"serviceProperties":
  {"name":"testrasteranalysis",
    "serviceUrl":"https://<server name>/server/rest/services/Hosted/testrasteranalysis/ImageServer"},
  "itemProperties":{"itemId":"8cfbd3ec25584d0d8f4ed23b8ff7c43b","folderId":"sdfwerfbd3ec25584d0d8f4"}
}

optimizeFor

Choose the optimization method to use for calculating the viewshed.

This parameter offers two methods: SPEED and ACCURACY.

  • SPEED is optimized for processing speed, trading some accuracy in the result for higher performance. This is the default.
  • ACCURACY is optimized for accuracy, at the expense of a longer processing time.

Syntax: A string describing the optimization method.

Example:

"optimizeFor": "ACCURACY"

maximumViewingDistance

This is a cutoff distance where the computation of visible areas stops. Beyond this distance, it is unknown whether the analysis points and the other objects can see each other.

The value must be supplied through either the maximumViewingDistance parameter or the maximumViewingDistanceField parameter.

Syntax: A linear unit specifying the distance and units.

Supported units: Meters | Kilometers | Feet | Yards | Miles

Example:

"maximumViewingDistance": {"distance": <value>, "units": <unit>}

maximumViewingDistanceField

Provide a field that specifies the maximum viewing distance for each observer. You can use any numerical field from the input observer point features.

The value contained in the field must be in the same unit as the XY unit of the input elevation surface.

Syntax: A string that represents a field name.

Example:

"maximumViewingDistanceField":"radius2"

minimumViewingDistance

This is a distance where the computation of visible areas begins.

The value must be supplied through either the minimumViewingDistance parameter or the minimumViewingDistanceField parameter.

Syntax: A linear unit specifying the distance and units.

Supported units: Meters | Kilometers | Feet | Yards | Miles

Example:

"minimumViewingDistance": {"distance": <value>, "units": <units>}

minimumViewingDistanceField

Provide a field that specifies the minimum viewing distance for each observer.

You can use any numerical field from the input observer point features. The value contained in the field must be in the same unit as the XY unit of the input elevation surface.

Syntax: A string that represents a field name.

Example:

"minimumViewingDistanceField": "radius1

viewingDistanceIs3D

Specify whether the minimumViewingDistance and maximumViewingDistance input parameters are measured in a three-dimensional or two-dimensional way.

Syntax: A Boolean value as either true or false.

  • If true, the viewing distances are measured in 3D.
  • If false, the viewing distances are measured in 2D. This is the default.
observersElevation

Specify the elevation of your observer locations.

The value must be supplied through either the observersElevation parameter or the observersElevationField parameter.

Syntax: A linear unit specifying the elevation and units.

Supported units: Meters | Kilometers | Feet | Yards | Miles

Example:

"observersElevation": {"distance": <value>, "units": <unit>}

observersElevationField

Provide a field that specifies the elevation for the observers.

You can use any numerical field from the input observer point features. The value contained in the field must be in the same unit as the Z unit of the input elevation surface.

Syntax: A string that represents a field name.

Example:

"observersElevationField": "spot"

observersHeight

The height above ground of your observer locations.

The value must be supplied through either the observersHeight or observersHeightField parameters. During the viewshed calculation, this value is added to the observer elevation if it is specified; otherwise, it is added to the interpolated surface z-value.

Syntax: A linear unit specifying the height and units.

Supported units: Meters | Kilometers | Feet | Yards | Miles

Example:

"observersHeight": {"distance": <value>, "units": <unit>}

observersHeightField

Provide a field that specifies the height for the observers. You can use any numerical field from the input observer point features.

The value contained in the field must be in the same unit as the Z unit of the input elevation surface.

Syntax: A string that represents a field name.

Example:

"observersHeightField": "offseta"

targetHeight

Enter the height of structures, or people on the ground, used to establish visibility.

The value must be supplied through either the targetHeight parameter or the targetHeightField parameter.

Syntax: A linear unit specifying the height and units.

Supported units: Meters | Kilometers | Feet | Yards | Miles

Example:

"targetHeight": {"distance": <value>, "units": <unit>}

targetHeightField

Provide a field that specifies the height for the targets. You can use any numerical field from the input observer point features.

The value contained in the field must be in the same unit as the Z unit of the input elevation surface.

Syntax: A string that represents a field name.

Example:

"targetHeightField": "offsetb"

aboveGroundLevelOutputName

The optional above ground level output image service name.

You can specify the name, or you can create an empty service using Portal Admin Sharing API and use the return JSON object as input to this parameter.

Syntax: A JSON object describes the name of the output or the output raster.

Output name example:

"aboveGroundLevelOutputName":{"serviceProperties":{"name":"testagl"}}

Output raster examples:

//Output Portal item
"aboveGroundLevelOutputName":{"itemId": <portal item id>}

//Output URL
"aboveGroundLevelOutputName":{"url": <image service url}

//Output raster layer service
"aboveGroundLevelOutputName":{"serviceProperties": 
  {"name":"testagl",
  "serviceUrl":"https://<server name>/server/rest/services/Hosted/testrasteranalysis/ImageServer"},
  "itemProperties":{"itemID":"8cfbd3ec25584d0d8f4ed23b8ff7c43b","folderId":"sdfwerfbd3ec25584d0d8f4"}
}

context

Contains additional settings that affect task execution. This task has the following settings:

  • Extent (extent): A bounding box that defines the analysis area.
  • Output Spatial Reference (outSR): The output raster will be projected into the output spatial reference.
  • Snap Raster (snapRaster): The output raster will have its cells aligned with the specified snap raster.
  • Cell Size (cellSize): The output raster will have the resolution specified by cell size.
  • Mask (mask): Only cells that fall within the analysis mask will be considered in the operation.
f

The response format. The default response format is html.

Values: html | json

Response

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

{
  "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 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:

https://<raster analysis tools url>/CreateViewshed/jobs/<jobId>

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

https://<raster analysis tools url>/CreateViewshed/jobs/<jobId>/results/<output parameters>

Example usage

Below is a sample request URL for CreateViewshed.

https://services.myserver.com/arcgis/rest/services/System/RasterAnalysisTools/GPServer/CreateViewshed/submitJob

JSON response syntax

The response returns the outputRaster output parameter, which has properties for parameter name, data type, and value. The content of value is always the output raster dataset itemId and the image service URL.

{
  "paramName": <parameter name>,
  "dataType": "GPString",
  "value": {
    "itemId": <item Id>,
    "url": <URL>
  }
}

JSON response example

{
  "paramName": "outRaster",
  "dataType": "GPString",
  "value": {
    "itemId": "f121390b85ef419790479fc75b493efd", 
    "url": "https://<server name>/arcgis/rest/services/Hosted/<service name>/ImageServer"
  }
}