public static double RhumbDistance(LatLonPoint from, LatLonPoint to)
{
double rhumbBearing = RhumbBearing(from, to);
double distance = 0.0;
double deltaCoLat = (to.Latitude - from.Latitude) * DEG_TO_RAD;
if (rhumbBearing == 90.0 || rhumbBearing == 270.0)
distance = Math.Abs(EARTH_RADIUS * Math.Cos(from.Latitude) * ((to.Longitude - from.Longitude) * DEG_TO_RAD));
else
distance = Math.Abs((deltaCoLat * EARTH_RADIUS) / Math.Cos(rhumbBearing * DEG_TO_RAD));
return distance;
}
public static double RhumbBearing(LatLonPoint from, LatLonPoint to)
{
double rhumbBearing = 0.0;
double deltaLong = (to.Longitude * DEG_TO_RAD) - (from.Longitude * DEG_TO_RAD);
double latFactor1 = Math.Log(Math.Tan((Math.PI / 4.0) + ((from.Latitude * DEG_TO_RAD) / 2.0)));
double latFactor2 = Math.Log(Math.Tan((Math.PI / 4.0) + ((to.Latitude * DEG_TO_RAD) / 2.0)));
double deltaLatFactor = latFactor2 - latFactor1;
if (deltaLatFactor == 0 && deltaLong == 0)
rhumbBearing = 0;
else
rhumbBearing = (360 + ((Math.Atan2(deltaLong, deltaLatFactor) * 180.0) / Math.PI)) % 360;
return rhumbBearing;
}
