Gets the location based on a start point, a heading and a distance.

GetLocationFromHeading.cs

using System;

namespace CodeFormulaOfTheDay
{
	/// <summary>
	/// Extension methods for geodesic calculations.
	/// </summary>
	public static class Geodesic
	{
		/// <summary>
		/// Earth circumference in meters used for distance calculations - based on WGS84 ellipsoid. Change this to miles or kilometers to get
		/// inputs/outputs in those units
		/// </summary>
		private const double EarthCircumference = 6378137;

		/// <summary>
		/// Gets the location based on a start point, a heading and a distance.
		/// </summary>
		/// <param name="startLat">The start latitude.</param>
		/// <param name="startLong">The start longitude.</param>
		/// <param name="distanceMeters">The distance in meters travelled in the direction of <c>heading</c>.</param>
		/// <param name="heading">The heading in degrees.</param>
		/// <param name="locationLat">The location latitude.</param>
		/// <param name="locationLong">The location longitude.</param>
		public static void GetLocationFromHeading(double startLat, double startLong, double distanceMeters, double heading,
			out double locationLat, out double locationLong)
		{
			double brng = heading / 180 * Math.PI;
			double lon1 = startLong / 180 * Math.PI;
			double lat1 = startLat / 180 * Math.PI;
			double dR = distanceMeters / EarthCircumference; //Angular distance in radians
			double lat2 = Math.Asin(Math.Sin(lat1) * Math.Cos(dR) + Math.Cos(lat1) * Math.Sin(dR) * Math.Cos(brng));
			double lon2 = lon1 + Math.Atan2(Math.Sin(brng) * Math.Sin(dR) * Math.Cos(lat1), Math.Cos(dR) - Math.Sin(lat1) * Math.Sin(lat2));
			double lon = lon2 / Math.PI * 180;
			double lat = lat2 / Math.PI * 180;
			while (lon < -180) lon += 360;
			while (lat < -90) lat += 180;
			while (lon > 180) lon -= 360;
			while (lat > 90) lat -= 180;
			locationLat = lat;
			locationLong = lon;
		}
	}
}