static double polarRadius = 6356752.314245D; // Semi-minor axis b
#endregion Fields
#region Methods
// flat earth approximation
public static void GetCourseAndDistance(wptType pt1, wptType pt2, ref double course, ref double dist)
{
// convert latitude and longitude to radians
double lat1 = DegreesToRadians((double)pt1.lat);
double lon1 = DegreesToRadians((double)pt1.lon);
double lat2 = DegreesToRadians((double)pt2.lat);
double lon2 = DegreesToRadians((double)pt2.lon);
// compute latitude and longitude differences
double dlat = lat2 - lat1;
double dlon = lon2 - lon1;
double distanceNorth = dlat;
double distanceEast = dlon * Math.Cos(lat1);
// compute the distance in radians
dist = Math.Sqrt(distanceNorth * distanceNorth + distanceEast * distanceEast);
// and convert the radians to meters
dist = RadiansToMeters(dist);
// add the elevation difference to the calculation
double dele = (double)pt2.ele - (double)pt1.ele;
dist = Math.Sqrt(dist * dist + dele * dele);
// compute the course
course = Math.Atan2(distanceEast, distanceNorth) % (2 * Math.PI);
course = RadiansToDegrees(course);
if (course < 0)
course += 360;
}
/// <summary>
/// Distance between two WayPoints from GPX
/// </summary>
/// <param name="wpt1"></param>
/// <param name="wpt2"></param>
/// <returns></returns>
public static double Haversine(wptType wpt1, wptType wpt2)
{
// convert latitude and longitude to radians
double lat1 = DegreesToRadians((double)wpt1.lat);
double lon1 = DegreesToRadians((double)wpt1.lon);
double lat2 = DegreesToRadians((double)wpt2.lat);
double lon2 = DegreesToRadians((double)wpt2.lon);
return Haversine( lat1, lon1, lat2, lon2, (double)wpt2.ele, (double)wpt1.ele);
}