ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.Geometry Namespace / EllipticArcBuilderEx Class / StartAngle Property
Example Version

StartAngle Property (EllipticArcBuilderEx)
Gets or sets the start angle in radians.
Syntax
public double StartAngle {get; set;}

Property Value

A double representing the start angle.
Exceptions
ExceptionDescription
The StartAngle is NaN.
Remarks
The start angle is the angle of the line defined by the CenterPoint and the StartPoint. If RotationAngle != 0, then the start angle is relative to the rotated SemiMajorAxis rather than the X-axis. The start angle is is measured in radians and is always between -PI and +PI. Changing the start angle may also change the start point and central angle.
Example
Elliptic Arc Builder Properties
// retrieve the curve's properties
EllipticArcBuilderEx builder = new EllipticArcBuilderEx(arcSegment);
MapPoint startPt = builder.StartPoint;
MapPoint endPt = builder.EndPoint;
Coordinate2D centerPt = builder.CenterPoint;
bool isCircular = builder.IsCircular;
bool isMinor = builder.IsMinor;
double startAngle = builder.StartAngle;
double endAngle = builder.EndAngle;
double centralAngle = builder.CentralAngle;
double rotationAngle = builder.RotationAngle;
ArcOrientation orientation = builder.Orientation;
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also