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Profile task

The Profile task is used to sample elevation values along input lines. The output polyline feature can be used to create a profile graph.

In synchronous mode, the maximum number of input line features that can be accepted by the task for each request is 100.

Request URL

https://elevation.arcgis.com/arcgis/rest/services/Tools/ElevationSync/GPServer/Profile/execute

Description

The output from this task are polyline features with elevation values extracted along the input line features for each vertex. The elevation values are stored as z-values in the shape geometry. The distance values are stored as m-values in the shape geometry. The input polyline vertices are densified using the input maximum sample distance.

Depending on the DEM resolution selected, different data sources will be used by the task.

  • By default, this task currently works worldwide between 60 degrees north and 56 degrees south based on the 3 arc-second (approximately 90-meter) resolution SRTM dataset.
  • For 30m, the task will use 1 arc-second resolution data in North America (Canada, United States, and Mexico) from the USGS National Elevation Dataset (NED), SRTM DEM-S dataset from Geoscience Australia in Australia and SRTM data between 60 degrees north and 56 degrees south in the remaining parts of the world (Africa, South America, most of Europe and continental Asia, the East Indies, New Zealand, and islands of the western Pacific).
  • For 24m, the task will use 0.8 arc-second (approximately 24-meter) data from the global dataset WorldDEM4Ortho from Airbus Defence and Space GmbH, excluding the countries of Azerbaijan, DR Congo, and Ukraine.
  • For 10m, the task will use 1/3 arc-second resolution data in the continental United States from USGS National Elevation Dataset (NED) and approximately 10-meter data covering Norway, Finland, Denmark, Austria, Spain, and Japan from various authoritative sources.
  • For 1,000m, the task will use the GEBCO data covering the entire world at 30 arc-second (approximately 1,000-meter) resolution.

Refer to the locator map to see the areas covered and to learn more about the data sources currently available.

Usage

  • The task will return an error message if the specified resolution is not available at any of the input feature locations.

  • The maximum number of input lines is 100 for the synchronous profile task. If additional input lines are provided, the task will return an error and will not execute.

  • When the Maximum Sample Distance parameter is empty or not supplied, a default sampling distance is calculated based on how many vertices are available on the input line feature. If the input line feature contains fewer than 50 vertices, the default sampling distance is the length of the input line feature divided by 49. If the input has 50 or more, but fewer than 200 vertices, the default sampling distance is the length of the input line feature divided by 199. If the number of vertices is from 200 to the maximum of 1,024, the input line feature will not be densified if the Maximum Sample Distance parameter is empty or not specified.

  • The returned line features are in the same coordinate system as the input line features. The z- and m-values of the vertices are in meters.

  • The maximum number of elevation values returned from the task is 2,000 for each input line. The task will return an error message and will not execute if a request results in more than this maximum number of elevation values. If this occurs, you should either specify a larger sampling distance, or input a line feature with fewer vertices, or both.

  • The output field Length Meters holds the planimetric length of the profile line calculated as a geodesic distance and is the correct length regardless of the coordinate system of the data. This length will be different from the shape_length attribute due to the effects of map projection distortion. The output field DEMResolution records the source DEM resolution used by the task. Three additional output fields are also available that identify the DEM data source used in the calculation. Those fields are Product Name, Source, and Source URL.

  • When submitting the execute request for the synchronous Profile task, returnZ and returnM must be specified as true and included in the request parameters in order to get the Z (elevation) and M (distance) values.

    An example of an execute string with the Z and M enabled is provided in a subsequent section.

Request Parameters

ParameterDescription

InputLineFeatures

(Required)

The line features that will be profiled over the surface.

  • Type: Feature Set

  • Syntax:

    {
    "geometryType":"geometryType",
    "spatialReference":<spatialReference>,
    "fields":<fields>,
    "features":<features>,
    }

ProfileIDField

A unique identifier to tie profiles to their corresponding input line features.

  • Type: String

DEMResolution

The approximate spatial resolution (cell size) of the source elevation data used for the calculation.

The resolution values are an approximation of the spatial resolution of the digital elevation model. While many elevation sources are distributed in units of arc seconds, the keyword is an approximation of those resolutions in meters for easier understanding.

  • Type: String

  • Values: FINEST | 10m | 24m | 30m | 90m | 1000m

MaximumSampleDistance

The maximum sampling distance along the line to sample elevation values.

  • Type: Double

MaximumSampleDistanceUnits

The units for the MaximumSampleDistance.

  • Type: String

  • Values: Meters | Kilometers | Feet | Yards | Miles

  • Default: Meters

Complete request example

The profile elevation and distance values are stored as the Z and M values in the result feature set. When submitting the request to execute the synchronous Profile task, returnZ and returnM must be set to true and included in the request parameters.

The following is an example of the complete form of an execute request:

https://elevation.arcgis.com/arcgis/rest/services/Tools/ElevationSync/GPServer/Profile/execute?f=json&InputLineFeatures=<line feature>&ProfileIDField=OID&DEMResolution=FINEST&MaximumSampleDistance=13&MaximumSampleDistanceUnits=Meters&returnZ=true&returnM=true

Response

If the request is successful, the response from the Profile task is a polyline FeatureSet. The number of returned line features is the same as the number of line features in the input. The following example illustrates the returned JSON structure for a successful request:

JSON response syntax for successful request
{
 "results": [{
  "paramName": "OutputProfile",
  "dataType": "GPFeatureRecordSetLayer",
  "value": {
   "displayFieldName": "",
   "geometryType": "esriGeometryPolyline",
   "spatialReference": {
    "wkid": <value>,
    "latestWkid": <value>
   },
   "fields": [
    {
     <field1>
    },
    {
     <field2>
    },
    {
     <additional fields>
    }    
   ],
   "features": [{
    "attributes": {
     "OBJECTID": 1,
     "DEMResolution": <value>,
     "ProfileLength": <value>,
     "Shape_Length": <value>
    },
    "geometry": {"paths": [[
     [
      x,
      y, 
      z,
      m
     ],
     [
      x,
      y,
      z,
      m
     ],
     [
      <additional points>
     ]],
     [
      <additional polylines>
     ]]}
     }],
   "exceededTransferLimit": false
	 }
 }],
 "messages": []
}