# Neighborhood Summary Statistics (Spatial Statistics)

## Summary

Calculates summary statistics of one or more numeric fields using local neighborhoods around each feature. The local statistics include mean (average), median, standard deviation, interquartile range, skewness, and quantile imbalance. All statistics can be geographically weighted using kernels to give more influence to neighbors closer to the focal feature. Various neighborhood types can be used, including distance band, number of neighbors, polygon contiguity, Delaunay triangulation, and spatial weights matrix files (.swm). Summary statistics are also calculated for the distances to the neighbors of each feature.

## Illustration ## Usage

• In addition to any analysis fields provided, statistics based on distances to neighbors are calculated for each feature. This allows you to calculate, for example, the mean and standard deviation of the distances to each neighbor to see if the neighbors are generally close or far away from the focal feature. The statistics for distance to neighbors will not use the focal feature in its calculations because that distance is always zero. Additionally, these statistics will not be geographically weighted because it is not meaningful to weight distance values based on those same distances.

• When the Delaunay triangulation option is chosen for the Neighborhood Type parameter, the output feature class is called a Voronoi Map.

• If the input features are polygons, all distances between polygons are defined by the distances between polygon centroids.

• The local statistics can only be geographically weighted if the Neighborhood Type parameter is specified as Number of Neighbors or Distance Band because neighborhoods based on polygon contiguity or Delaunay triangulation should not be weighted by centroid-to-centroid distance. If Get spatial weights from file is specified for the Neighborhood Type parameter, the weights defined in the spatial weights file are automatically used for geographic weighting.

• If the Output Coordinate System environment is set to a geographic coordinate system with latitude and longitude coordinates, all distances are calculated using chordal distance. Otherwise, all distances are calculated using straight-line (Euclidean) distance.

• If you choose to ignore null values using the Ignore Null Values in Calculations parameter, neighbors with null values in the analysis field will be filtered out after searching for neighbors. This may result in fewer neighbors than you expect, and if multiple analysis fields are provided, some may use a different number of neighbors than others. This is particularly apparent when the Number of Neighbors option is specified for the Neighborhood Type parameter.

## Parameters

 Label Explanation Data Type Input Features The point or polygon features that will be used to calculate the local statistics. Feature Layer Output Features The output feature class containing the local statistics as fields. Each statistic of each analysis field will be stored as an individual field. Feature Class Analysis Fields (Optional) One or more fields for which local statistics will be calculated. If no analysis fields are provided, only local statistics based on distances to neighbors will be calculated. Field Local Summary Statistic (Optional) Specifies the local summary statistic that will be calculated for each analysis field. All—All local statistics will be calculated. This is the default.Mean—The local mean (average) will be calculated.Median— The local median will be calculated.Standard deviation—The local standard deviation will be calculated.Interquartile range— The local interquartile range will be calculated.Skewness— The local skewness will be calculated.Quantile imbalance— The local quantile imbalance will be calculated. String Include Focal Feature in Calculations (Optional) Specifies whether the focal feature will be included when calculating local statistics for each feature.Checked—The focal feature and all of its neighbors will be included when calculating local statistics. This is the default.Unchecked—The focal feature will not be included when calculating local statistics. Only neighbors of the feature will be included. Boolean Ignore Null Values in Calculations (Optional) Specifies whether null values in the analysis fields will be included or ignored in the calculations.Checked—Null values in the analysis fields will be ignored, and statistics will be calculated using only non-null values. This is the default.Unchecked—Null values in the analysis fields will be included in the calculations, and any local statistic will be calculated as null if any of the values used in the calculation are null. Boolean Neighborhood Type (Optional) Specifies how neighbors will be chosen for each input feature. To calculate local statistics, neighboring features must be identified for each input feature, and these neighbors are used to calculate the local statistics for each feature. For point features, the default is Delaunay triangulation. For polygon features, the default is Contiguity edges corners. The Delaunay triangulation option is only available with a Desktop Advanced license.Distance band—Features within a specified critical distance of each feature will be included as neighbors.Number of neighbors— The closest features will be included as neighbors. Contiguity edges only— Polygon features that share an edge will be included as neighbors.Contiguity edges corners— Polygon features that share an edge or a corner will be included as neighbors. This is the default for polygon features.Delaunay triangulation—Features whose Delaunay triangulation share an edge will be included as neighbors. This is the default for point features.Get spatial weights from file— Neighbors and weights will be defined by a specified spatial weights file. String Distance Band (Optional) All features within this distance will be included as neighbors. If no value is provided, one will be estimated during processing and included as a geoprocessing message. If the specified distance results in more than 1,000 neighbors, only the closest 1,000 features will be included as neighbors. Linear Unit Number of Neighbors (Optional) The number of neighbors that will be included for each local calculation. The number does not include the focal feature. If the focal feature is included in calculations, one additional neighbor will be used. The default is 8. Long Weights Matrix File (Optional) The path and file name of the spatial weights matrix file that defines spatial, and potentially temporal, relationships among features. File Local Weighting Scheme (Optional) Specifies the weighting scheme that will be applied to neighbors when calculating local statistics. Unweighted—Neighbors will not be weighted. This is the default.Bisquare—Neighbors will be weighted using a bisquare kernel scheme.Gaussian—Neighbors will be weighted using a Gaussian kernel scheme. String Kernel Bandwidth (Optional) The bandwidth of the bisquare or Gaussian local weighting schemes. If no value is provided, one will be estimated during processing and included as a geoprocessing message. Linear Unit

`arcpy.stats.NeighborhoodSummaryStatistics(in_features, output_features, {analysis_fields}, {local_summary_statistic}, {include_focal_feature}, {ignore_nulls}, {neighborhood_type}, {distance_band}, {number_of_neighbors}, {weights_matrix_file}, {local_weighting_scheme}, {kernel_bandwidth})`
 Name Explanation Data Type in_features The point or polygon features that will be used to calculate the local statistics. Feature Layer output_features The output feature class containing the local statistics as fields. Each statistic of each analysis field will be stored as an individual field. Feature Class analysis_fields[analysis_fields,...](Optional) One or more fields for which local statistics will be calculated. If no analysis fields are provided, only local statistics based on distances to neighbors will be calculated. Field local_summary_statistic(Optional) Specifies the local summary statistic that will be calculated for each analysis field. ALL—All local statistics will be calculated. This is the default.MEAN—The local mean (average) will be calculated.MEDIAN— The local median will be calculated.STD_DEV—The local standard deviation will be calculated.IQR— The local interquartile range will be calculated.SKEWNESS— The local skewness will be calculated.QUANTILE_IMBALANCE— The local quantile imbalance will be calculated. String include_focal_feature(Optional) Specifies whether the focal feature will be included when calculating local statistics for each feature.INCLUDE_FOCAL—The focal feature and all of its neighbors will be included when calculating local statistics. This is the default.EXCLUDE_FOCAL—The focal feature will not be included when calculating local statistics. Only neighbors of the feature will be included. Boolean ignore_nulls(Optional) Specifies whether null values in the analysis fields will be included or ignored in the calculations.IGNORE_NULLS—Null values will be ignored in the local calculations.INCLUDE_NULLS—Null values will be included in the local calculations. Boolean neighborhood_type(Optional) Specifies how neighbors will be chosen for each input feature. To calculate local statistics, neighboring features must be identified for each input feature, and these neighbors are used to calculate the local statistics for each feature. For point features, the default is Delaunay triangulation. For polygon features, the default is Contiguity edges corners. The Delaunay triangulation option is only available with a Desktop Advanced license.DISTANCE_BAND—Features within a specified critical distance of each feature will be included as neighbors.NUMBER_OF_NEIGHBORS— The closest features will be included as neighbors. CONTIGUITY_EDGES_ONLY— Polygon features that share an edge will be included as neighbors.CONTIGUITY_EDGES_CORNERS— Polygon features that share an edge or a corner will be included as neighbors. This is the default for polygon features.DELAUNAY_TRIANGULATION—Features whose Delaunay triangulation share an edge will be included as neighbors. This is the default for point features.GET_SPATIAL_WEIGHTS_FROM_FILE— Neighbors and weights will be defined by a specified spatial weights file. String distance_band(Optional) All features within this distance will be included as neighbors. If no value is provided, one will be estimated during processing and included as a geoprocessing message. If the specified distance results in more than 1,000 neighbors, only the closest 1,000 features will be included as neighbors. Linear Unit number_of_neighbors(Optional) The number of neighbors that will be included for each local calculation. The number does not include the focal feature. If the focal feature is included in calculations, one additional neighbor will be used. The default is 8. Long weights_matrix_file(Optional) The path and file name of the spatial weights matrix file that defines spatial, and potentially temporal, relationships among features. File local_weighting_scheme(Optional) Specifies the weighting scheme that will be applied to neighbors when calculating local statistics. UNWEIGHTED—Neighbors will not be weighted. This is the default.BISQUARE—Neighbors will be weighted using a bisquare kernel scheme.GAUSSIAN—Neighbors will be weighted using a Gaussian kernel scheme. String kernel_bandwidth(Optional) The bandwidth of the bisquare or Gaussian local weighting schemes. If no value is provided, one will be estimated during processing and included as a geoprocessing message. Linear Unit

### Code sample

NeighborhoodSummaryStatistics example 1 (Python window)

The following Python window script demonstrates how to use the NeighborhoodSummaryStatistics tool.

``````import arcpy
arcpy.env.workspace = r"c:\data\project_data.gdb"
arcpy.stats.NeighborhoodSummaryStatistics("USCounties",
"USCounties_NeighborhoodSummaryStatistics", "POP2018;POP2019",
"ALL", "INCLUDE_FOCAL", "IGNORE_NULLS", "NUMBER_OF_NEIGHBORS", None,
8, None, "UNWEIGHTED")``````
NeighborhoodSummaryStatistics example 2 (stand-alone script)

The following stand-alone script demonstrates how to use the NeighborhoodSummaryStatistics tool.

``````# Calculate a focal mean for the population and income of US cities.

import arcpy

# Set the current workspace
arcpy.env.workspace = r"c:\data\project_data.gdb"

# Calculate the local mean of POP2020 and MedIncome2020 fields
# using 8 nearest neighbors.

arcpy.stats.NeighborhoodSummaryStatistics("USCities", "USCities_Mean",
"POP2020;MedIncome2020", "MEAN", "EXCLUDE_FOCAL", "IGNORE_NULLS",
"NUMBER_OF_NEIGHBORS", None, 8, None, "GAUSSIAN", "50 Miles")``````

## Licensing information

• Basic: Limited
• Standard: Limited