/// <a href="http://bit.ly/2Oq9xlg">Give a starting coordinate, a distance and a direction, calculate and return a destination coordinate.</a>
public static Coordinates Destination(Coordinates start, double distanceKm, double bearingDegrees)
{
start = start.ToRadians();
var bearingRadians = Trig.ToRadians(bearingDegrees);
var deltaDistance = distanceKm / EarthMeanRadiusKm;
var sinDeltaDistance = Math.Sin(deltaDistance);
var cosDeltaDistance = Math.Cos(deltaDistance);
var sinStartLatitude = Math.Sin(start.Latitude);
var cosStartLatitude = Math.Cos(start.Latitude);
var latitude = Math.Asin(
(sinStartLatitude * cosDeltaDistance) +
cosStartLatitude * sinDeltaDistance * Math.Cos(bearingRadians));
var longitude = start.Longitude + Math.Atan2(
Math.Sin(bearingRadians) * sinDeltaDistance * cosStartLatitude,
cosDeltaDistance - sinStartLatitude * Math.Sin(latitude));
return(Coords(latitude, longitude, radians: true));
}
/// <a href="http://bit.ly/2Oq9qpQ">Convert to degrees if needed.</a> public Coordinates ToDegrees() => Radians?Coords(Trig.ToDegrees(Latitude), Trig.ToDegrees(Longitude), true) : this;
/// <a href="http://bit.ly/2Oq9qpQ">Convert to radians if needed</a> public Coordinates ToRadians() => Radians ? this : Coords(Trig.ToRadians(Latitude), Trig.ToRadians(Longitude), true);
/// <a href="http://bit.ly/2Oq9oOK">Return the bearing in degrees to get from one point to another.</a> public static double BearingDegrees(Coordinates from, Coordinates to) => Trig.ToDegrees(BearingRadians(from, to));