/// <summary>
/// Returns the pitch relative to an idealized horizon of "to" from the perspective of "from".
/// </summary>
/// <param name="from"></param>
/// <param name="to"></param>
/// <returns></returns>
public static Angle GetRelativePitch(Location from, Location to)
{
double x = GetFlatDistance(from, to).Kilometers;
double y = to.Altitude.Kilometers - from.Altitude.Kilometers;
return new Angle(Math.Atan2(y, x), Units.Angular.Radians);
}
/// <summary>
/// Returns an angle indicating the bearing of "to" relative to "from".
/// </summary>
/// <param name="from"></param>
/// <param name="to"></param>
/// <returns></returns>
public static Angle GetBearing(Location from, Location to)
{
double a = Math.Sin(to.Longitude.Radians - from.Longitude.Radians) * Math.Cos(to.Latitude.Radians);
double b = Math.Cos(from.Latitude.Radians) * Math.Sin(to.Latitude.Radians);
double c = Math.Sin(from.Latitude.Radians) * Math.Cos(to.Latitude.Radians) * Math.Cos(to.Longitude.Radians - from.Longitude.Radians);
double d = Math.Atan2(a, b - c) % ( 2 * Math.PI);
return new Angle(d, Units.Angular.Radians);
}
/// <summary>
/// Returns the distance between two locations, taking into account altitude differences.
/// </summary>
/// <param name="from"></param>
/// <param name="to"></param>
/// <returns></returns>
public static Distance GetActualDistance(Location from, Location to)
{
double a = GetFlatDistance(from, to).Kilometers;
double b = Math.Abs(to.Altitude.Kilometers - from.Altitude.Kilometers);
double c = Math.Sqrt(Math.Pow(a, 2) + Math.Pow(b, 2));
return new Distance(c, Units.Linear.Kilometers);
}
/// <summary>
/// Returns the distance between two locations, ignoring altitude differences. (Haversine formula)
/// </summary>
/// <param name="from"></param>
/// <param name="to"></param>
/// <returns></returns>
public static Distance GetFlatDistance(Location from, Location to)
{
double dLat = to.Latitude.Radians - from.Latitude.Radians;
double dLong = to.Longitude.Radians - from.Longitude.Radians;
double a = Math.Pow(Math.Sin(dLat/2), 2) + (Math.Pow(Math.Sin(dLong/2), 2) * Math.Cos(from.Latitude.Radians) * Math.Cos(to.Latitude.Radians));
double c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
Distance RadiusOfEarth = new Distance(RadiusOfEarthKm, Units.Linear.Kilometers);
return new Distance(c * RadiusOfEarth.Kilometers, Units.Linear.Kilometers);
}