ArcGIS Pro 3.1 API Reference Guide
ArcGIS.Core.Geometry Namespace / EllipticArcSegment Class / StartAngle Property
Example

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    StartAngle Property (EllipticArcSegment)
    In This Topic
    Gets the start angle in radians.
    Syntax
    public double StartAngle {get;}
    Public ReadOnly Property StartAngle As Double

    Property Value

    A double representing the start angle.
    Remarks
    The start angle is the angle of the line defined by the CenterPoint and the Segment.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.
    Example
    Elliptic Arc Properties
    // retrieve the curve's control points
    EllipticArcSegment arc = EllipticArcBuilderEx.CreateEllipticArcSegment(arcSegment);
    MapPoint startPt = arc.StartPoint;
    MapPoint endPt = arc.EndPoint;
    Coordinate2D centerPt = arc.CenterPoint;
    bool isCircular = arc.IsCircular;
    bool isMinor = arc.IsMinor;
    bool isCounterClockwise = arc.IsCounterClockwise;
    bool isCurve = arc.IsCurve;
    double len = arc.Length;
    double ratio = arc.MinorMajorRatio;
    
    double semiMajorAxis, semiMinorAxis;
    // get the axes
    arc.GetAxes(out semiMajorAxis, out semiMinorAxis);
    // or use the properties
    // semiMajorAxis = arc.SemiMajorAxis;
    // semiMinorAxis = arc.SemiMinorAxis;
    
    double startAngle, centralAngle, rotationAngle;
    // or use QueryCoords to get complete information
    arc.QueryCoords(out centerPt, out startAngle, out centralAngle, out rotationAngle, out semiMajorAxis, out semiMinorAxis);
    
    // use properties to get angle information
    //double endAngle = arc.EndAngle;
    //centralAngle = arc.CentralAngle;
    //rotationAngle = arc.RotationAngle;
    //startAngle = arc.StartAngle;
    
    Requirements

    Target Platforms: Windows 11, Windows 10

    ArcGIS Pro version: 3.0 or higher.
    See Also