Point Statistics (Spatial Analyst)

Available with Spatial Analyst license.

Summary

Calculates a statistic on the points in a neighborhood around each output cell.

Learn more about how Point Statistics works

Usage

• The Output cell size can be defined by a numeric value or obtained from an existing raster dataset. If the cell size hasn’t been explicitly specified as the parameter value, it is derived from the Cell Size environment if it has been specified. If the parameter cell size or the environment cell size have not been specified, but the Snap Raster environment has been set, the cell size of the snap raster is used. If nothing is specified, the cell size is calculated from the shorter of the width or height of the extent divided by 250, in which the extent is in the Output Coordinate System specified in the environment.

• If the cell size is specified using a numeric value, the tool will use it directly for the output raster.

  If the cell size is specified using a raster dataset, the parameter will show the path of the raster dataset instead of the cell size value. The cell size of that raster dataset will be used directly in the analysis, provided the spatial reference of the dataset is the same as the output spatial reference. If the spatial reference of the dataset is different than the output spatial reference, it will be projected based on the selected Cell Size Projection Method.

• When the specified field is integer, the available overlay statistic choices are Mean, Majority, Maximum, Median, Minimum, Minority, Range, Standard deviation, Sum, and Variety. When the field is floating point, the only allowed statistics are Mean, Maximum, Minimum, Range, Standard deviation, and Sum.

• For statistic types Majority, Maximum, Median, Minimum, Minority, Range, and Sum, the output data type of the raster will be the same as the input field type. For statistic types Mean and Standard deviation, the output raster will always be floating point. For Variety, the output raster will always be integer.

• If there are no points in the neighborhood of a raster cell, the Variety statistic assigns it a value of 0. For the other statistics, NoData is assigned.

• See Analysis environments and Spatial Analyst for additional details on the geoprocessing environments that apply to this tool.

Parameters

Dialog

Label	Explanation	Data Type
Input point features	The input point features for which to calculate the statistics in a neighborhood around each output cell. The input can be either a point or multipoint feature class.	Feature Layer
Field	The field for which the specified statistic will be calculated. It can be any numeric field of the input features. It can be the Shape field if the input features contain z-values.	Field
Output cell size (Optional)	The cell size of the output raster that will be created. This parameter can be defined by a numeric value or obtained from an existing raster dataset. If the cell size hasn't been explicitly specified as the parameter value, the environment cell size value will be used if specified; otherwise, additional rules will be used to calculate it from the other inputs. See the usage section for more detail.	Analysis Cell Size
Neighborhood (Optional)	The area around each processing cell within which any input points found will be used in the statistics calculation. There are several predefined neighborhood types to choose from. Once the neighbourhood type is selected, other parameters can be set to fully define the shape, size and units of measure. The default neighborhood is a rectangle. The following are the forms of the available neighborhood types: Annulus, Inner radius, Outer radius, Units type A torus (donut-shaped) neighborhood defined by an inner radius and an outer radius. The default annulus is an inner radius of one cell and an outer radius of three cells. Circle, Radius, Units type A circular neighborhood with the given radius. The default radius is three cells. Rectangle, Height, Width, Units type A rectangular neighborhood defined by height and width. The default is a square with a height and width of three cells. Wedge, Radius, Start angle, End angle, Units type A wedge-shaped neighborhood defined by a radius, the start angle, and the end angle. The wedge extends counterclockwise from the starting angle to the ending angle. Angles are specified in degrees, with 0 or 360 representing east. Negative angles can be used. The default wedge is from 0 to 90 degrees, with a radius of three cells. The distance units for the parameters can be specified in Cell units or Map units. Cell units is the default.	Neighborhood
Statistics type (Optional)	Specifies the statistic type to be calculated. Mean —The average of the field values in each neighborhood will be calculated. Majority —The most frequently occurring field value in each neighborhood will be identified. In the case of a tie, the lower value is used. Maximum —The largest field value in each neighborhood will be identified. Median —The median field value in each neighborhood will be calculated. In the case of an even number of points in the neighborhood, the result will be the lower of the two middle values. Minimum —The smallest field value in each neighborhood will be identified. Minority —The least frequently occurring field value in each neighborhood will be identified. In the case of a tie, the lower value is used. Range —The range (the difference between the largest and smallest) of the field values in each neighborhood will be calculated. Standard Deviation —The standard deviation of the field values in each neighborhood will be calculated. Sum —The sum of the field values in the neighborhood will be calculated. Variety —The number of unique field values in each neighborhood will be calculated.	String

Return Value

Label	Explanation	Data Type
Output raster	The output point statistics raster.	Raster

Python

PointStatistics(in_point_features, field, {cell_size}, {neighborhood}, {statistics_type})

Name	Explanation	Data Type
in_point_features	The input point features for which to calculate the statistics in a neighborhood around each output cell. The input can be either a point or multipoint feature class.	Feature Layer
field	The field for which the specified statistic will be calculated. It can be any numeric field of the input features. It can be the Shape field if the input features contain z-values.	Field
cell_size (Optional)	The cell size of the output raster that will be created. This parameter can be defined by a numeric value or obtained from an existing raster dataset. If the cell size hasn't been explicitly specified as the parameter value, the environment cell size value will be used if specified; otherwise, additional rules will be used to calculate it from the other inputs. See the usage section for more detail.	Analysis Cell Size
neighborhood (Optional)	The area around each processing cell within which any input points found will be used in the statistics calculation. There are several predefined neighborhood types to choose from. Once the neighbourhood type is selected, other parameters can be set to fully define the shape, size and units of measure. The default neighborhood is a rectangle. The shape of the neighborhoods around each input point are defined by the Neighborhood class. The available neighborhood types are NbrAnnulus, NbrCircle, NbrRectangle, and NbrWedge. The following are the forms of the available neighborhood types: NbrAnnulus({innerRadius}, {outerRadius}, {units}) A torus (donut-shaped) neighborhood defined by an inner radius and an outer radius. The default annulus is an inner radius of one cell and an outer radius of three cells. NbrCircle({radius}, {units} A circular neighborhood with the given radius. The default radius is three cells. NbrRectangle({width}, {height}, {units}) A rectangular neighborhood defined by height and width. The default is a square with a height and width of three cells. NbrWedge({radius}, {startAngle}, {endAngle}, {units}) A wedge-shaped neighborhood defined by a radius, the start angle, and the end angle. The wedge extends counterclockwise from the starting angle to the ending angle. Angles are specified in degrees, with 0 or 360 representing east. Negative angles can be used. The default wedge is from 0 to 90 degrees, with a radius of three cells. The distance units for the parameters can be specified in CELL units or MAP units. Cell units is the default. The default neighborhood type is NbrRectangle with a height and width of three cells.	Neighborhood
statistics_type (Optional)	Specifies the statistic type to be calculated. The calculation is performed on the values of the specified field of the points that fall within the specified neighborhood of each output raster cell. MEAN —The average of the field values in each neighborhood will be calculated. MAJORITY —The most frequently occurring field value in each neighborhood will be identified. In the case of a tie, the lower value is used. MAXIMUM —The largest field value in each neighborhood will be identified. MEDIAN —The median field value in each neighborhood will be calculated. In the case of an even number of points in the neighborhood, the result will be the lower of the two middle values. MINIMUM —The smallest field value in each neighborhood will be identified. MINORITY —The least frequently occurring field value in each neighborhood will be identified. In the case of a tie, the lower value is used. RANGE —The range (the difference between the largest and smallest) of the field values in each neighborhood will be calculated. STD —The standard deviation of the field values in each neighborhood will be calculated. SUM —The sum of the field values in the neighborhood will be calculated. VARIETY —The number of unique field values in each neighborhood will be calculated. The available choices for the statistics type is determined by the numeric type of the specified field. If the field is integer, all the statistics types are available. If the field is floating point, only the maximum, mean, minimum, range, standard deviation and sum statistics are available.	String

Return Value

Name	Explanation	Data Type
out_raster	The output point statistics raster.	Raster

Code sample

PointStatistics example 1 (Python window)

This example determines a statistic (the sum) on the input shapefile point features that fall in a circular neighborhood around each output raster cell.

import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outPointStats = PointStatistics("ca_ozone_pts.shp", "OZONE", 500, 
                                NbrCircle(10000, "MAP"), "SUM")
outPointStats.save("C:/sapyexamples/output/pointstatsout")

PointStatistics example 2 (stand-alone script)

This example determines a statistic (the average) on the input shapefile point features that fall in a circular neighborhood around each output raster cell.

# Name: PointStatistics_Ex_02.py
# Description: Calculates a statistic on points over a specified 
#    neighborhood outputting a raster.
# Requirements: Spatial Analyst Extension

# Import system modules
import arcpy
from arcpy import env
from arcpy.sa import *

# Set environment settings
env.workspace = "C:/sapyexamples/data"

# Set local variables
inPointFeatures = "ca_ozone_pts.shp"
field = "OZONE"
cellSize = 500
neighborhood = NbrCircle(6000, "MAP")

# Execute PointStatistics
outPointStatistics = PointStatistics(inPointFeatures, field, cellSize,
                                     neighborhood, "MEAN")

# Save the output 
outPointStatistics.save("C:/sapyexamples/output/pointstatout")

Environments

Auto Commit, Cell Size, Cell Size Projection Method, Compression, Current Workspace, Extent, Geographic Transformations, Output CONFIG Keyword, Output Coordinate System, Scratch Workspace, Snap Raster, Tile Size

Licensing information

• Basic: Requires Spatial Analyst
• Standard: Requires Spatial Analyst
• Advanced: Requires Spatial Analyst