API Question How to get the coordinates in a distance of n meters?

[Topper]

what's th best way to get the coordinates (lat and lng) in a distance of n meters into the direction of the vessels heading using orbiter api?

Sorry but I'm still confused with all the transformations...

---------- Post added 26-09-15 at 01:16 ---------- Previous post was 25-09-15 at 23:45 ----------

Ok I thing I got it:

	VECTOR3 loc, glob, horz;
	loc.x = 0;
	loc.y = 0;
	loc.z = distance;
	

	double heading = ORBITERTOOLS::getFlightVectorHeading(v);
	//oapiGetHeading(v->GetHandle(),&heading);	
	double x, z;
	//Performce a 2D rotation so that nose is pointing into z direction
	x =  loc.x * cos(-heading) + loc.z * sin(heading);
	z = -loc.x * sin(-heading) - loc.z * cos(heading);

	 
	loc.x = x;
	loc.y = 0;
	loc.z = z;

	double lng, lat, rad;
	v->HorizonInvRot(loc,horz);
	v->Local2Global(horz,glob);
	
	oapiGlobalToEqu(v->GetGravityRef(),glob,&lng,&lat, &rad);

But it seems to have strange results...
So can someone say me if it's seems to be corect please?

[Edit]

ok I got a good and easy solution now:

void pointRadialDistance(double lat1, double lon1, double bearing, double distance, VESSEL * v, double *lat2, double *lon2)
{
	double rdistance = distance / oapiGetSize(v->GetGravityRef());
	* lat2 = asin(sin(lat1) * cos(rdistance) + cos(lat1) * sin (rdistance) * cos(bearing) );
	* lon2 = lon1 + atan2( sin (bearing) * sin (rdistance) * cos (lat1), cos (rdistance) - sin(lat1) * sin (* lat2 ));
}