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Zonal Characterization (Spatial Analyst Tools)

Summary

Summarizes the values of multiple rasters within the zones of another dataset and reports the results as a table.

Learn more about how zonal statistics tools work

Usage

  • The following are example applications of the tool:

    • Calculate the mean precipitation, maximum temperature, and sum of population within different ecosystem zones to estimate sustainable agricultural practices.

    • Estimate the mean elevation, mean slope, and sum of NDVI values for each plot to locate areas suitable for planting shade trees.

  • A zone is defined as all areas in the input that have the same value. The areas do not have to be contiguous. Both rasters and features can be used for the zone input.

  • If the Input Raster or Feature Zones (in_zone_raster_or_features in Python) parameter value is a raster, it must be an integer raster.

  • If the Input Raster or Feature Zones parameter value is a feature, it will be converted to a raster internally using the cell size, cell alignment, and spatial reference from the Input Value Rasters (in_value_rasters_statistics in Python) parameter value with the smallest cell size, unless otherwise specified in the analysis environment. This will trigger an internal resampling before the zonal operation is performed.

  • If the Input Raster or Feature Zones parameter value is a feature, for any of the zone features that do not overlap any cell centers of a value raster, those zones will not be converted to the internal zone raster. As a result, those zones will not be represented in the output. You can manage this by determining an appropriate value for the cell size environment that will preserve the desired level of detail of the feature zones, and specify it in the analysis environment.

  • If the Input Raster or Feature Zones value is a point feature, more than one point may be contained in any particular cell of the input value rasters. For such cells, the zone value is determined by the point with the lowest ObjectID field (for example, OID or FID).

  • If the Input Raster or Feature Zones value has overlapping features, the zonal analysis will be performed for each individual feature.

  • When the cell size of the Input Raster or Feature Zones and the Input Value Rasters parameter values are different, the cell size, cell alignment and spatial reference from the Input Value Rasters parameter value with the smallest cell size will be used, unless otherwise specified in the analysis environment. This will trigger an internal resampling before the zonal operation is performed.

    When the zone and value inputs are all rasters of the same cell size and the cells are aligned, they will be used directly in the tool and will not be resampled internally during tool processing.

  • When specifying the Input Raster or Feature Zones value, the default Zone Field (zone_field in Python) parameter value will be the first available integer field (for example, OID or FID) for features, and the VALUE field for raster. The zone field can be an integer or a string field type.

  • The supported statistics type depends on the data type of the Input Value Rasters parameter value, and the statistics calculation type specified by the Calculate Circular Statistics parameter value.

    If the data type is integer, the arithmetic statistics calculation supports the Mean, Majority, Majority count, Majority percentage, Maximum, Median, Minimum, Minority, Minority count, Minority percentage, Percentile, Range, Standard deviation, Sum, and Variety options. The circular statistics calculation supports the Mean, Majority, Minority, Standard deviation, and Variety options.

    If the data type is float, the arithmetic statistics calculation supports the Mean, Maximum, Median, Minimum, Percentile, Range, Standard deviation, and Sum options. The circular statistics calculation supports the Mean and Standard deviation options.

  • For majority and minority calculations, when there is a tie, the output will be the lowest of the tied values.

  • To calculate more than one statistics type per value raster, the same value raster needs to be specified multiple times. If the same value raster and statistics type combination is duplicated, the tool will generate an error.

  • To calculate circular statistics, check the Calculate Circular Statistics parameter (circular_calculation = "CIRCULAR" in Python), and specify a value for the Circular Wrap Value parameter (circular_wrap_value in Python).

    If the Calculate Circular Statistics parameter is checked, circular statistics will be calculated for all value rasters with the specified circular wrap value applied.

  • Supported multidimensional raster dataset types include multidimensional raster layer, mosaic, image service, and Esri CRF.

  • When processing as all slices of multidimensional rasters, the Output Statistics Table and Output Statistics Feature Class parameter values will only contain date information and will not contain time when in DBF and SHP formats. When in FGDB format, the output table and feature class will include time information along with date in the Standard Time field.

  • The Output Statistics Table (out_statistics_table in Python) parameter value will have the following characteristics:

    • The number of rows in the output table is the number of zones within the analysis extent.

    • A series of fields will be created in the output table to represent the zones, with the count and statistics values for each Input Value Rasters and Statistics Type parameter value.

    • The names of the fields are derived from the value raster name and statistics type by default, unless specified in the Field Name parameter. For circular statistics, the name of the field will include C_ before the specified statistic. For example, the field name will be ValueRasterName_MEAN for the arithmetic mean statistic and ValueRasterName_C_MEAN for the circular mean statistic.

    • The maximum length of the field names in the output table will depend on the workspace.

    • The data type for each value of the items in the output table will depend on the zonal calculation being performed. See How zonal statistics tools work for the specific behavior of a statistic.

  • For the Output Statistics Feature Class (out_statistics_features in Python) parameter value, if the zone input is a raster, the output feature class will be converted to features without generalizing and by honoring the analysis environment.

    If the zone input is a raster containing noncontiguous zones, the tool will create single-part polygons in the output statistics feature class. The output statistics feature class will contain the same statistics calculated in the output statistics table appended to each single-part polygon in the respective zone.

  • This tool will use the following environment settings:

    • The value raster with the smallest cell size will be used as the analysis cell size, output coordinate system, and snap raster by default.

    • The default extent will be the intersection of the zone with the union of all the value rasters.

    • By default, this tool will use up to 80 percent of all multicore processors if available.

      For a very large number of zones, use fewer number of cores for processing. To use a different number of cores, use the Parallel Processing Factor environment setting.

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

Parameters

Label Explanation Data type

Input Raster or Feature Zones

The dataset that defines the zones.

The zones can be defined by an integer raster or a feature layer.

Raster Layer; Feature Layer

Input Value Rasters

The collection of rasters whose values will each be summarized by a statistic.

A statistic will be calculated for all cells in each input value raster that belong to the same zone as the output cell.

The field names in the output statistics table will be derived from the value raster name and statistics type by default.

Value table columns:

  • Raster—An input value raster.

  • Statistics Type—The statistics type.

    • Mean—The average value of the cells will be calculated.

    • Majority—The cell value that occurs most often will be calculated.

    • Majority count—The frequency of all cells that contain the majority value will be calculated.

    • Majority percentage—The percentage of cells that contain the majority value will be calculated.

    • Maximum—The largest value of the cells will be calculated.

    • Median—The median or middle cell value will be calculated.

    • Minimum—The smallest cell value will be calculated.

    • Minority—The cell value that occurs least often will be calculated.

    • Minority count—The frequency of all cells that contain the minority value will be calculated.

    • Minority percentage—The percentage of cells that contain the minority value will be calculated.

    • Percentile—The percentile of the cell values will be calculated. The 90th percentile is calculated by default. You can specify other values (from 0 to 100) using the Percentile Values parameter.

    • Range—The difference between the largest and smallest cell values will be calculated.

    • Std—The standard deviation of the cell values will be calculated.

    • Sum—The total value of the cells will be calculated.

    • Variety—The number of unique cell values will be calculated.

  • Field Name—The field name for that raster in the output.

Value Table

Output Statistics Table

The output table that will contain the summary of the values in each zone for all value rasters.

The format of the table will be determined by the output location and path. By default, the output will be a geodatabase table if in a geodatabase workspace, and a dBASE table if in a file workspace.

Table

Output Statistics Feature Class

(Optional)

The output feature class that will be created by joining the output table to the input zone data.

Feature Class

Zone Field

(Optional)

The field that contains the values that define each zone.

It can be an integer or a string field of the zone dataset.

Field

Ignore NoData in Calculations

(Optional)

Specifies whether NoData values in the value input will be ignored in the results of the zone that they fall within.

  • Checked—Within any particular zone, only cells that have a value in the input value raster will be used in determining the output value for that zone. NoData cells in the value raster will be ignored in the statistic calculation. This is the default.

  • Unchecked—Within any particular zone, if NoData cells exist in the value raster, they will not be ignored and their existence indicates that there is insufficient information to perform statistical calculations for all the cells in that zone. Consequently, the entire zone will receive the NoData value.

Boolean

Percentile Values

(Optional)

The percentile that will be calculated. The default is 90, indicating the 90th percentile.

The values can range from 0 to 100. The 0th percentile is essentially equivalent to the minimum statistic, and the 100th percentile is equivalent to maximum. A value of 50 will produce essentially the same result as the median statistic.

This parameter is only available if the Statistics type parameter is set to Percentile or All.

Double

Percentile Interpolation Type

(Optional)

Specifies the method of interpolation that will be used when the percentile value falls between two cell values from the input value raster.

  • Auto-detect—If the input value raster is of integer pixel type, the Nearest method will be used. If the input value raster is of floating point pixel type, the Linear method will be used. This is the default.

  • Nearest—The nearest available value to the desired percentile will be used.

  • Linear—The weighted average of the two surrounding values from the desired percentile will be used.

String

Calculate Circular Statistics

(Optional)

Specifies how the input raster will be processed for circular data.

  • Checked—The statistics for angles or other cyclic quantities, such as compass direction in degrees, daytimes, and fractional parts of real numbers, will be calculated.

  • Unchecked—Ordinary linear statistics will be calculated. This is the default.

Boolean

Circular Wrap Value

(Optional)

The value that will be used to round a linear value to the range of a given circular statistic. It must be a positive integer or a floating-point value. The default value is 360 degrees.

This parameter is only supported if the Calculate Circular Statistics parameter is checked.

Double

Process as Multidimensional

(Optional)

Specifies how the input rasters will be calculated if they are multidimensional.

  • Checked—Statistics will be calculated for all dimensions of the input multidimensional dataset.

  • Unchecked—Statistics will be calculated from the current slice of the input multidimensional dataset. This is the default.

Boolean

Append Zone Attributes to Output Features

(Optional)

Specifies whether any of the additional zone attributes from the input zones will be appended to the output feature class.

  • Checked—Additional zone attributes from the input zones will be appended to the output feature class.

  • Unchecked—Only the zone ID field from the input zones will be appended to the output feature class. This is the default.

Boolean

Environments

Auto Commit, Cell Size, Cell Size Projection Method, Compression, Current Workspace, Extent, Geographic Transformations, Mask, Output CONFIG Keyword, Output Coordinate System, Parallel Processing Factor, Maintain fully qualified field names, Scratch Workspace, Snap Raster, Tile Size, Transfer Field Domain Descriptions

Licensing information

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