Calculate Density

inputLayer (Required)

The point layer on which the density will be calculated.

Syntax: As described in Feature input, this parameter can be one of the following:

• A URL to a feature service layer with an optional filter to select specific features
• A URL to a big data catalog service layer with an optional filter to select specific features
• A feature collection

REST examples

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//REST web example
{"url": "https://myportal.domain.com/server/rest/services/Hosted/hurricaneTrack/FeatureServer/0", "filter": "Month = 'September'"}
//REST scripting example
"inputLayer": {"url": "https://myportal.domain.com/server/rest/services/Hosted/hurricaneTrack/FeatureServer/0", "filter": "Month = 'September'"}

fields (Optional)

Provides one or more fields specifying the number of incidents at each location. You can calculate the density for multiple fields, and the count of points will always have the density calculated.

REST examples

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//REST web example
crimeRate, indicator
//REST scripting example
"fields": "crimeRate, indicator"

weight (Required)

The type of weighting applied to density calculations. This parameter supports two values: Uniform(default), which calculates a magnitude-per-area, and Kernel, which applies a kernel function to fit a smooth tapered surface to each point.

Values: Uniform| Kernel

REST examples

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//REST web example
Uniform
//REST scripting example
"weight": "Kernel"

binType (Required)

The type of bin used to calculate density.

Analysis using Square or Hexagon bins requires a projected coordinate system. When aggregating layers into bins, the input layer or processing extent (processSR ) must have a projected coordinate system. If a projected coordinate system is not specified when running analysis, a projection will be picked based on the extent of the data.

Values: Hexagon| Square

REST examples

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//REST web example
Hexagon
//REST scripting example
"binType": "Hexagon"

binSize (Required)

The distance for the bins that the inputLayerwill be analyzed using. When generating bins for the Squarebin type, the number and units specified determine the height and length of the square. For the Hexagonbin type, the number and units specified determine the distance between parallel sides.

REST examples

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//REST web example
108.3
//REST scripting example
"binSize": 100

binSizeUnit (Required)

The distance unit for the bins for which the density will be calculated and t he linear unit to be used with the value specified for binSize. The default is Meters.

Values: Meters | Kilometers | Feet | FeetInt | FeetUS | Miles |MilesInt | MilesUS | NauticalMiles | NauticalMilesInt | NauticalMilesUS | Yards | YardsInt | YardsUS

REST examples

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//REST web example
Meters
//REST scripting example
"binSizeUnit": "Miles"

timeStepInterval (Optional)

A numeric value that specifies duration of the time step interval. The default is none. This option is only available if the input points are time enabled and represent an instant in time.

REST examples

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//REST web example
20
//REST scripting example
"timeStepInterval": 20

timeStepIntervalUnit (Optional)

A string that specifies units of the time step interval. The default is none. This option is only available if the input points are time enabled and represent an instant in time.

Values: Milliseconds | Seconds | Minutes | Hours | Days | Weeks | Months | Years

REST examples

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//REST web example
Days
//REST scripting example
"timeStepIntervalUnit": "Days"

timeStepRepeatInterval (Optional)

A numeric value that specifies how often the time step repeat occurs. The default is none. This option is only available if the input points are time enabled and of time type instant.

REST examples

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//REST web example
2
//REST scripting example
"timeStepRepeatInterval": 2

timeStepRepeatIntervalUnit (Optional)

A string that specifies units of the time step interval. The default is none. This option is only available if the input points are time enabled and represent an instant in time.

REST examples

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//REST web example
Minutes
//REST scripting example
"timeStepRepeatIntervalUnit": "Minutes"

timeStepReference (Optional)

A date that specifies the reference time to align the time slices to, represented in milliseconds from epoch. The default is January 1, 1970, at 12:00 a.m. (epoch time stamp 0). This option is only available if the input points are time enabled and of time type instant.

REST examples

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//REST web example
946684800000
//REST scripting example
"timeStepReference": 946684800000

radius (Required)

The size of the neighborhood within which density will be calculated. The radius size must be larger than the binSizevalue.

REST examples

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//REST web example
100
//REST scripting example
"radius": "100"

radiusUnit (Required)

The distance unit for the radius defining the neighborhood for which density will be calculated and t he linear unit to be used with the value specified for binSize. The default is Meters.

Values: Meters | Kilometers | Feet | FeetInt | FeetUS | Miles |MilesInt | MilesUS | NauticalMiles | NauticalMilesInt | NauticalMilesUS | Yards | YardsInt | YardsUS

REST examples

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//REST web example
Miles
//REST scripting example
"radiusUnit": "Miles"

areaUnits (Optional)

The output units of the density values. The default value is SquareKilometers. If density values are very small, you can increase the size of the area units (for example, square meters to square kilometers) to return larger values. This value only scales the result.

Values: SquareMeters| SquareKilometers| Hectares| SquareFeet|SquareFeetInt| SquareFeetUS|SquareYards|SquareYardsInt| SquareYardsUS| SquareMiles| SquareMilesInt| SquareMilesUS| Acres| AcresInt| AcresUS

REST examples

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//REST web example
SquareMiles
//REST scripting example
"areaUnits": "SquareKilometers"

outputName (Required)

The task will create a feature service of the results. You define the name of the service.

REST examples

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//REST web example
myOutput
//REST scripting example
"outputName": "myOutput"

context (Optional)

The context parameter contains additional settings that affect task execution. For this task, there are four settings:

• Extent (extent )—A bounding box that defines the analysis area. Only those features that intersect the bounding box will be analyzed.
• Processing spatial reference (processSR )—The features will be projected into this coordinate system for analysis.
• Output spatial reference (outSR )—The features will be projected into this coordinate system after the analysis to be saved. The output spatial reference for the spatiotemporal big data store is always WGS84.
• Data store (dataStore )—Results will be saved to the specified data store. The default is the spatiotemporal big data store.

Syntax:

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{
  "extent": {extent},
  "processSR": {spatial reference},
  "outSR": {spatial reference},
  "dataStore": {data store}
}

f

The response format. The default response format is html .

Values: html | json | pjson

output

The outputvalue will always contain polygon features. The number of resulting polygons is based on the location of the inputLayervalue. The layer will have an attribute for each field on which the density has been calculated, as well as the density of the count of points.

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{"url": "https://<analysis-url>/CalculateDensity/jobs/<jobId>/results/output"}

The result has properties for parameter name, data type, and value. The contents of value depend on the outputName parameter provided in the initial request. The value contains the URL of the feature service layer.

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{
  "paramName": "output",
  "dataType": "GPRecordSet",
  "value":{"url": "<hosted featureservice layer url>"}
}

See Feature output for more information about how the result layer is accessed.