# Calculate Polygon Main Angle (Cartography)

## 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)
 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

## Code Sample

CalculatePolygonMainAngle tool Example (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")```
CalculatePolygonMainAngle tool Example (Stand-alone Python script)

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

```# Name: CalculatePolygonMainAngle_standalone_script.py
# Description: calculates an angle for a polygon based on the largest edge of the feature

# Import system modules
import arcpy
from arcpy import env

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

# Set local variables
in_features = "cities"
angle_field = "poly_angle"

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

ArcView: No
ArcEditor: Yes
ArcInfo: Yes

11/11/2011