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simgear/simgear/math/sg_geodesy.hxx
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#ifndef _SG_GEODESY_HXX
#define _SG_GEODESY_HXX
#include "SGMath.hxx"
// Compatibility header.
// Please use the SGGeodesy and SGMath functions directly.
/**
* Convert from geodetic coordinates to geocentric coordinates.
* WARNING: this function is non-reversible. Due to the fact that
* "up" is a different direction for geocentric and geodetic frames,
* you can not simply add your "alt" parameter to the "sl_radius"
* result and get back (via sgGeodToGeoc()) to the coordinates you
* started with. The error under normal conditions will be of
* centimeter order; whether that is important or not is application
* dependent. Consider using sgGeodToCart() instead.
*
* @param lat_geod (in) Geodetic latitude, radians, + = North
* @param alt (in) C.G. altitude above mean sea level (meters)
* @param sl_radius (out) SEA LEVEL radius to earth center (meters)
* @param lat_geoc (out) Geocentric latitude, radians, + = North
*/
inline void sgGeodToGeoc(double lat_geod, double alt,
double *sl_radius, double *lat_geoc)
{
SGVec3<double> cart;
SGGeod geod = SGGeod::fromRadM(0, lat_geod, alt);
SGGeodesy::SGGeodToCart(geod, cart);
SGGeoc geoc;
SGGeodesy::SGCartToGeoc(cart, geoc);
*lat_geoc = geoc.getLatitudeRad();
*sl_radius = SGGeodesy::SGGeodToSeaLevelRadius(geod);
}
/**
* Convert a cartesian point to a geodetic lat/lon/altitude.
*
* @param xyz (in) Pointer to cartesian point.
* @param lat (out) Latitude, in radians
* @param lon (out) Longitude, in radians
* @param alt (out) Altitude, in meters above the WGS84 ellipsoid
*/
inline void sgCartToGeod(const double* xyz, double* lat, double* lon, double* alt)
{
SGGeod geod;
SGGeodesy::SGCartToGeod(SGVec3<double>(xyz), geod);
*lat = geod.getLatitudeRad();
*lon = geod.getLongitudeRad();
*alt = geod.getElevationM();
}
/**
* Convert a geodetic lat/lon/altitude to a cartesian point.
*
* @param lat (in) Latitude, in radians
* @param lon (in) Longitude, in radians
* @param alt (in) Altitude, in meters above the WGS84 ellipsoid
* @param xyz (out) Pointer to cartesian point.
*/
inline void sgGeodToCart(double lat, double lon, double alt, double* xyz)
{
SGVec3<double> cart;
SGGeodesy::SGGeodToCart(SGGeod::fromRadM(lon, lat, alt), cart);
xyz[0] = cart(0);
xyz[1] = cart(1);
xyz[2] = cart(2);
}
/**
* Given a starting position and an offset radial and distance,
* calculate an ending positon on a wgs84 ellipsoid.
* @param alt (in) meters (unused)
* @param lat1 (in) degrees
* @param lon1 (in) degrees
* @param az1 (in) degrees
* @param s (in) distance in meters
* @param lat2 (out) degrees
* @param lon2 (out) degrees
* @param az2 (out) return course in degrees
*/
inline int geo_direct_wgs_84 ( double lat1, double lon1, double az1,
double s, double *lat2, double *lon2,
double *az2 )
{
SGGeod p2;
if (!SGGeodesy::direct(SGGeod::fromDeg(lon1, lat1), az1, s, p2, *az2))
return 1;
*lat2 = p2.getLatitudeDeg();
*lon2 = p2.getLongitudeDeg();
return 0;
}
inline int geo_direct_wgs_84 ( double alt, double lat1,
double lon1, double az1,
double s, double *lat2, double *lon2,
double *az2 )
{ return geo_direct_wgs_84(lat1, lon1, az1, s, lat2, lon2, az2); }
/**
* Given a starting position and an offset radial and distance,
* calculate an ending positon on a wgs84 ellipsoid.
* @param p1 (in) geodetic position
* @param az1 (in) degrees
* @param s (in) distance in meters
* @param p2 (out) geodetic position
* @param az2 (out) return course in degrees
*/
inline int geo_direct_wgs_84(const SGGeod& p1, double az1,
double s, SGGeod& p2, double *az2 )
{
return !SGGeodesy::direct(p1, az1, s, p2, *az2);
}
/**
* Given an altitude and two sets of (lat, lon) calculate great circle
* distance between them as well as the starting and ending azimuths.
* @param alt (in) meters (unused)
* @param lat1 (in) degrees
* @param lon1 (in) degrees
* @param lat2 (in) degrees
* @param lon2 (in) degrees
* @param az1 (out) start heading degrees
* @param az2 (out) end heading degrees
* @param s (out) distance meters
*/
inline int geo_inverse_wgs_84( double lat1, double lon1, double lat2,
double lon2, double *az1, double *az2,
double *s )
{
return !SGGeodesy::inverse(SGGeod::fromDeg(lon1, lat1),
SGGeod::fromDeg(lon2, lat2), *az1, *az2, *s);
}
inline int geo_inverse_wgs_84( double alt, double lat1,
double lon1, double lat2,
double lon2, double *az1, double *az2,
double *s )
{ return geo_inverse_wgs_84(lat1, lon1, lat2, lon2, az1, az2, s); }
/**
* Given an altitude and two sets of (lat, lon) calculate great circle
* distance between them as well as the starting and ending azimuths.
* @param p1 (in) first position
* @param p2 (in) fsecond position
* @param az1 (out) start heading degrees
* @param az2 (out) end heading degrees
* @param s (out) distance meters
*/
inline int geo_inverse_wgs_84(const SGGeod& p1, const SGGeod& p2,
double *az1, double *az2, double *s )
{
return !SGGeodesy::inverse(p1, p2, *az1, *az2, *s);
}
#endif // _SG_GEODESY_HXX