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# Calculate Polygon Main Angle

## Summary

Calculates the dominant angles of input polygon features and assigns the values to a specified field in the feature class.

## Usage

• The dominant angle of a polygon is the angle of longest collection of segments that have similar orientation. This angle will be stored in the specified field in decimal degrees from true north.

• Use this tool to determine the trend of a polygon and use the resulting angle to orient symbology such as markers or hatch lines within the polygon. This tool is meant for primarily orthogonal polygons rather than organically shaped ones.

## Syntax

`CalculatePolygonMainAngle_cartography (in_features, angle_field, {rotation_method})`
 Parameter Explanation Data Type in_features The input polygon features. Feature Layer angle_field The field that will be updated with the polygon main angle values. Field rotation_method(Optional) Controls the method and origin point of rotation. GEOGRAPHIC —Angle is calculated clockwise with 0 at top/north.ARITHMETIC —Angle is calculated counterclockwise with 0 at the right/east.GRAPHIC —Angle is calculated counterclockwise with 0 at top/north. This is the default. String

## Code sample

CalculatePolygonMainAngle tool example 1 (Python window)

The following Python window script demonstrates how to use the CalculatePolygonMainAngle tool in immediate mode.

``````import arcpy
from arcpy import env
env.workspace = "C:\data"

arcpy.CalculatePolygonMainAngle_cartography("cities", "poly_angle", "GEOGRAPHIC")``````
CalculatePolygonMainAngle tool example 2 (stand-alone Python script)

This stand-alone script shows an example of using the CalculatePolygonMainAngle tool.

``````# Name: CalculatePolygonMainAngle_standalone_script.py
# Description: Calculates the dominant angles of input polygon features and assigns the values to a specified field in the feature class

# Import system modules
import arcpy
from arcpy import env

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

# Set local variables
in_features = "cartography.gdb/buildings_area"
angle_field = "poly_angle"
rotation_method = "ARITHMETIC"

# Execute Calculate Polygon Main Angle
arcpy.CalculatePolygonMainAngle_cartography(in_features, angle_field, rotation_method)``````

## Licensing information

• ArcGIS Desktop Basic: No
• ArcGIS Desktop Standard: Yes
• ArcGIS Desktop Advanced: Yes