Calculate Density (Raster Analysis)

Summary

Creates a density map from point or line features by spreading known quantities of some phenomenon (represented as attributes of the points or lines) across the map. The result is a layer of areas classified from least dense to most dense.

A barrier can be used to alter the influence of a feature while calculating density.

Illustration

Usage

• This raster analysis portal tool is available when you are signed in to an ArcGIS Enterprise portal that has an ArcGIS Image Server configured for Raster Analysis . When the tool is invoked, ArcGIS Pro serves as a client and the processing occurs in the servers federated with ArcGIS Enterprise. The portal tool accepts layers from your portal as input and creates output in your portal.

  The input feature layer can be a layer from the portal or a URI or URL to a feature service. While you can use local feature data and layers as input to this portal tool, best practice is to use layers from your portal as input.

• Larger values of the radius parameter produce a density raster that is smoother. Smaller values produce a raster that changes more abruptly. If no value is provided, the tool will calculate one based on the number of points and their coordinates.

• Only the points or portions of a line that fall within the neighborhood are considered when calculating density. If no points or line sections fall within the neighborhood of a particular cell, the density of that cell will be zero.

Parameters

Dialog

Label	Explanation	Data Type
Input Point or Line Features	The input point or line features that will be used to calculate the density raster.	Feature Set
Output Name	The name of the output raster service. The default name is based on the tool name and the input layer name. If the layer name already exists, you will be prompted to provide another name.	String
Count Field (Optional)	A field indicating the number of incidents at each location. For example, if you are making a population density raster, and the input points are cities, it is appropriate to use the population of the city for the count field so cities with larger populations have more impact on the density calculations.	Field
Search Distance (Optional)	The search distance and units for the distance. When calculating the density of a cell, all features within this distance will be used in the density calculation for that cell. The units can be Kilometers, Meters, Miles, or Feet. The default units are Meters.	Linear Unit
Output Area Units (Optional)	Specifies the units that will be used for calculating area. Density is count divided by area, and this parameter sets the units of the area in the density calculation. Square Meters—Calculate the density per square meter. This is the default. Square Kilometers—Calculate the density per square kilometer. Square Feet—Calculate the density per square foot. Square Miles—Calculate the density per square mile.	String
Output Cell Size (Optional)	The cell size and units for the output raster. The units can be Kilometers, Meters, Miles, or Feet. The default units are Meters.	Linear Unit
Input Barrier Features (Optional)	The dataset that defines the barriers. The barriers can be a feature layer of polyline or polygon features.	Feature Set

Derived Output

Label	Explanation	Data Type
Output Raster	The output raster.	Raster Layer

Python

arcpy.ra.CalculateDensity(inputPointOrLineFeatures, outputName, {countField}, {searchDistance}, {outputAreaUnits}, {outputCellSize}, {inBarriers})

Name	Explanation	Data Type
inputPointOrLineFeatures	The input point or line features that will be used to calculate the density raster.	Feature Set
outputName	The name of the output raster service. The default name is based on the tool name and the input layer name. If the layer name already exists, you will be prompted to provide another name.	String
countField (Optional)	A field indicating the number of incidents at each location. For example, if you are making a population density raster, and the input points are cities, it is appropriate to use the population of the city for the count field so cities with larger populations have more impact on the density calculations.	Field
searchDistance (Optional)	The search distance and units for the distance. When calculating the density of a cell, all features within this distance will be used in the density calculation for that cell. The units can be Kilometers, Meters, Miles, or Feet. The default units are Meters.	Linear Unit
outputAreaUnits (Optional)	Specifies the units that will be used for calculating area. Density is count divided by area, and this parameter sets the units of the area in the density calculation. Square Meters—Calculate the density per square meter. This is the default. Square Kilometers—Calculate the density per square kilometer. Square Feet—Calculate the density per square foot. Square Miles—Calculate the density per square mile.	String
outputCellSize (Optional)	The cell size and units for the output raster. The units can be Kilometers, Meters, Miles, or Feet. The default units are Meters.	Linear Unit
inBarriers (Optional)	The dataset that defines the barriers. The barriers can be a feature layer of polyline or polygon features.	Feature Set

Derived Output

Name	Explanation	Data Type
outputRaster	The output raster.	Raster Layer

Code sample

CalculateDensity example 1 (Python window)

This example creates a density image service raster from points with a population field.

import arcpy

arcpy.ra.CalculateDensity('https://MyPortal.esri.com/server/rest/services/Hosted/myPoints/FeatureServer/0',
                          'outImgServ', 'Population','150000 Meters', 'Square Kilometers','10000 Meters', 
                          'https://MyPortal.esri.com/server/rest/services/Hosted/myPoints/FeatureServer/1')

CalculateDensity example 2 (stand-alone script)

This example creates a density image service raster from points with a population field.

#-------------------------------------------------------------------------------
# Name: CalculateDensity_example02.py
# Description: Creates a density image service raster from points with a population.
#
# Requirements: ArcGIS Image Server

# Import system modules
import arcpy

# Set local variables
inPoints = 'https://MyPortal.esri.com/server/rest/services/Hosted/myPoints/FeatureServer/0'
outRaster = 'outImgServ'
inField = 'Population'
searchDistance = '150000 Meters'
areaUnit = 'Square Kilometers'
outCellSize = '10000 Meters'
inBarriers = 'https://MyPortal.esri.com/server/rest/services/Hosted/myPoints/FeatureServer/1'

# Execute CalculateDensity
arcpy.ra.CalculateDensity(inPoints, outRaster, inField, searchDistance, areaUnit, outCellSize, inBarriers)

Environments

Extent, Cell Size, Mask, Output Coordinate System, Pyramid, Snap Raster

Licensing information

• Basic: Requires ArcGIS Image Server
• Standard: Requires ArcGIS Image Server
• Advanced: Requires ArcGIS Image Server