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Standard Distance (Spatial Statistics)

Release 9.2
Last modified January 9, 2009
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Measures the degree to which features are concentrated or dispersed around the points (or feature centroids) in an input feature class.

Learn about how Standard Distance works


Illustration

Standard Distance illustration

Usage tips

Command line syntax
An overview of the Command Line window
StandardDistance_stats <Input_Feature_Class> <Output_Standard_Distance_Feature_Class> <1 Standard Deviation | 2 Standard Deviations | 3 Standard Deviations> {Weight_Field} {Case_Field}

Parameter Explanation Data Type
<Input_Feature_Class>

A feature class containing a distribution of features for which the standard distance will be calculated.

Feature Layer
<Output_Standard_Distance_Feature_Class>

A polygon feature class that will contain a circle polygon for each input center. These circle polygons graphically portray the standard distance at each center point.

Feature Class
<1 Standard Deviation | 2 Standard Deviations | 3 Standard Deviations>

The size of output circles in standard deviations. The default circle size is 1; valid choices are 1, 2, or 3 standard deviations.

String
{Weight_Field}

The numeric field used to weight locations according to their relative importance.

Field
{Case_Field}

Field used to group features for separate standard distance calculations. The case field can be of numeric, date, or string type.

Field
Data types for geoprocessing tool parameters


Command line example

workspace e:\project93\data
StandardDistance robberies.shp robbery_SD.shp '2 Standard Deviation' LOSS_VAL TYPE

Scripting syntax
About getting started with writing geoprocessing scripts
StandardDistance_stats (Input_Feature_Class, Output_Standard_Distance_Feature_Class, Circle_Size, Weight_Field, Case_Field)

Parameter Explanation Data Type
Input_Feature_Class (Required)

A feature class containing a distribution of features for which the standard distance will be calculated.

Feature Layer
Output_Standard_Distance_Feature_Class (Required)

A polygon feature class that will contain a circle polygon for each input center. These circle polygons graphically portray the standard distance at each center point.

Feature Class
Circle_Size (Required)

The size of output circles in standard deviations. The default circle size is 1; valid choices are 1, 2, or 3 standard deviations.

String
Weight_Field (Optional)

The numeric field used to weight locations according to their relative importance.

Field
Case_Field (Optional)

Field used to group features for separate standard distance calculations. The case field can be of numeric, date, or string type.

Field

Data types for geoprocessing tool parameters


Script example

# Measure the geographic distribution of auto thefts
# Import system modules
import arcgisscripting

# Create the Geoprocessor object
gp = arcgisscripting.create()

# Local variables...
workspace = "C:/data"
auto_theft_locations = "AutoTheft.shp"
auto_theft_links = "AutoTheft_links.shp"
auto_theft_sd = "auto_theft_SD.shp"
auto_theft_se = "auto_theft_SE.shp"
auto_theft_ldm = "auto_theft_LDM.shp"

try:
    # Set the workspace (to avoid having to type in the full path to the data every time)
    gp.Workspace = workspace

    # Process: Standard Distance of auto theft locations...
    gp.StandardDistance_stats(auto_theft_locations, auto_theft_sd, "1 Standard Deviation", "#", "#")

    # Process: Directional Distribution (Standard Deviational Ellipse) of auto theft locations...
    gp.DirectionalDistribution_stats(auto_theft_locations, auto_theft_se, "1 Standard Deviation", "#", "#")

    # Process: Linear Directional Mean of auto thefts...
    gp.DirectionalMean_stats(auto_theft_links, auto_theft_linear, "false", "#")

except:
    # If an error occurred while running a tool, print the messages 
    print gp.GetMessages()

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