兩個座標計算之間的軸承奇怪的輸出

Question

我有一個方法，這是假設計算兩個地理座標之間的方位（以40.7486，-73.9864示例格式）。

但是，我有一個問題，它計算的標題與我使用久經考驗的應用程序計算的標題不同。

例如，以下各點之間的初始軸承是074度，但是我的方法返回047
40.7486, -73.9864
40.9486, -72.9866

下面是代碼中的相關SNIPPIT。

 /// <summary> 
    /// Calculate the inital bearing between two Locations 
    /// </summary> 
    /// <param name="pointA"></param> 
    /// <param name="pointB"></param> 
    /// <param name="headingType"></param> 
    /// <returns></returns> 
    public static double BearingToLocation(Location pointA, Location pointB) 
    { 
     // Convert both locations from degrees to radians 
     pointA = LocationToRad(pointA); 
     pointB = LocationToRad(pointB); 

     double partOne = exMath.Sin(pointB.Longitude - pointA.Longitude) * exMath.Cos(pointB.Latitude); 
     double partTwo = exMath.Cos(pointA.Latitude) * exMath.Sin(pointB.Latitude) - exMath.Sin(pointA.Latitude) * exMath.Cos(pointB.Latitude) * exMath.Cos(pointB.Longitude - pointA.Longitude); 
     double heading = AdditionalMath.ToDeg(exMath.Atan2(partOne, partTwo) % 2 * exMath.PI); 

     // Solve for compass wrap around 
     if (heading < 0) 
      heading += 360; 

     return heading; 
    } 

    /// <summary> 
    /// Return a new location in radians 
    /// </summary> 
    /// <param name="pointA"></param> 
    /// <returns></returns> 
    public static Location LocationToRad(Location pointA) 
    { 
     return new Location(AdditionalMath.ToRad(pointA.Latitude), AdditionalMath.ToRad(pointA.Longitude), pointA.Altitude); 
    } 

} 

/// <summary> 
/// Misc. math functions not available in Elze Kool's lib 
/// </summary> 
public static class AdditionalMath 
{ 
    /// <summary> 
    /// Degrees to radians 
    /// </summary> 
    /// <param name="x"></param> 
    /// <returns></returns> 
    public static double ToRad(double x) 
    { 
     return exMath.PI * x/180.00F; 
    } 

    /// <summary> 
    /// Radians to degrees 
    /// </summary> 
    /// <param name="x"></param> 
    /// <returns></returns> 
    public static double ToDeg(double x) 
    { 
     return x * 180.00F/exMath.PI; 
    } 
} 

任何人都可以看到這個問題嗎？我看了一遍，找不到問題。

Answer 1

的%看起來腥這一行：

double heading = AdditionalMath.ToDeg(exMath.Atan2(partOne, partTwo) % 2 * exMath.PI);