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flightgear/Math/fg_geodesy.hxx
1999-01-27 04:46:14 +00:00

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// fg_geodesy.hxx -- routines to convert between geodetic and geocentric
// coordinate systems.
//
// Copied and adapted directly from LaRCsim/ls_geodesy.c
//
// See below for the complete original LaRCsim comments.
//
// $Id$
// (Log is kept at end of this file)
#ifndef _FG_GEODESY_HXX
#define _FG_GEODESY_HXX
#ifndef __cplusplus
# error This library requires C++
#endif
#include <Math/point3d.hxx>
#include <Math/polar3d.hxx>
// fgGeocToGeod(lat_geoc, radius, *lat_geod, *alt, *sea_level_r)
// INPUTS:
// lat_geoc Geocentric latitude, radians, + = North
// radius C.G. radius to earth center (meters)
//
// OUTPUTS:
// lat_geod Geodetic latitude, radians, + = North
// alt C.G. altitude above mean sea level (meters)
// sea_level_r radius from earth center to sea level at
// local vertical (surface normal) of C.G. (meters)
void fgGeocToGeod( double lat_geoc, double radius, double
*lat_geod, double *alt, double *sea_level_r );
// fgGeodToGeoc( lat_geod, alt, *sl_radius, *lat_geoc )
// INPUTS:
// lat_geod Geodetic latitude, radians, + = North
// alt C.G. altitude above mean sea level (meters)
//
// OUTPUTS:
// sl_radius SEA LEVEL radius to earth center (meters)
// (add Altitude to get true distance from earth center.
// lat_geoc Geocentric latitude, radians, + = North
//
void fgGeodToGeoc( double lat_geod, double alt, double *sl_radius,
double *lat_geoc );
// convert a geodetic point lon(radians), lat(radians), elev(meter) to
// a cartesian point
inline Point3D fgGeodToCart(const Point3D& geod) {
double gc_lon, gc_lat, sl_radius;
// printf("A geodetic point is (%.2f, %.2f, %.2f)\n",
// geod[0], geod[1], geod[2]);
gc_lon = geod.lon();
fgGeodToGeoc(geod.lat(), geod.radius(), &sl_radius, &gc_lat);
// printf("A geocentric point is (%.2f, %.2f, %.2f)\n", gc_lon,
// gc_lat, sl_radius+geod[2]);
Point3D pp = Point3D( gc_lon, gc_lat, sl_radius + geod.radius());
return fgPolarToCart3d(pp);
}
/***************************************************************************
TITLE: ls_geodesy
----------------------------------------------------------------------------
FUNCTION: Converts geocentric coordinates to geodetic positions
----------------------------------------------------------------------------
MODULE STATUS: developmental
----------------------------------------------------------------------------
GENEALOGY: Written as part of LaRCSim project by E. B. Jackson
----------------------------------------------------------------------------
DESIGNED BY: E. B. Jackson
CODED BY: E. B. Jackson
MAINTAINED BY: E. B. Jackson
----------------------------------------------------------------------------
MODIFICATION HISTORY:
DATE PURPOSE BY
930208 Modified to avoid singularity near polar region. EBJ
930602 Moved backwards calcs here from ls_step. EBJ
931214 Changed erroneous Latitude and Altitude variables to
*lat_geod and *alt in routine ls_geoc_to_geod. EBJ
940111 Changed header files from old ls_eom.h style to ls_types,
and ls_constants. Also replaced old DATA type with new
SCALAR type. EBJ
CURRENT RCS HEADER:
$Header$
$Log$
Revision 1.4 1999/01/27 04:46:15 curt
Portability tweaks by Bernie Bright.
Revision 1.3 1998/10/18 01:17:11 curt
Point3D tweaks.
Revision 1.2 1998/10/16 23:36:37 curt
c++-ifying.
Revision 1.1 1998/10/16 19:30:42 curt
Renamed .c -> .h so we can start adding c++ supporting routines.
Revision 1.4 1998/07/08 14:40:08 curt
polar3d.[ch] renamed to polar3d.[ch]xx, vector.[ch] renamed to vector.[ch]xx
Updated fg_geodesy comments to reflect that routines expect and produce
meters.
Revision 1.3 1998/04/21 17:03:48 curt
Prepairing for C++ integration.
Revision 1.2 1998/01/22 02:59:38 curt
Changed #ifdef FILE_H to #ifdef _FILE_H
Revision 1.1 1997/07/31 23:13:14 curt
Initial revision.
Revision 1.1 1997/05/29 00:09:56 curt
Initial Flight Gear revision.
* Revision 1.5 1994/01/11 18:47:05 bjax
* Changed include files to use types and constants, not ls_eom.h
* Also changed DATA type to SCALAR type.
*
* Revision 1.4 1993/12/14 21:06:47 bjax
* Removed global variable references Altitude and Latitude. EBJ
*
* Revision 1.3 1993/06/02 15:03:40 bjax
* Made new subroutine for calculating geodetic to geocentric; changed name
* of forward conversion routine from ls_geodesy to ls_geoc_to_geod.
*
----------------------------------------------------------------------------
REFERENCES:
[ 1] Stevens, Brian L.; and Lewis, Frank L.: "Aircraft
Control and Simulation", Wiley and Sons, 1992.
ISBN 0-471-61397-5
----------------------------------------------------------------------------
CALLED BY: ls_aux
----------------------------------------------------------------------------
CALLS TO:
----------------------------------------------------------------------------
INPUTS:
lat_geoc Geocentric latitude, radians, + = North
radius C.G. radius to earth center, ft
----------------------------------------------------------------------------
OUTPUTS:
lat_geod Geodetic latitude, radians, + = North
alt C.G. altitude above mean sea level, ft
sea_level_r radius from earth center to sea level at
local vertical (surface normal) of C.G.
--------------------------------------------------------------------------*/
#endif // _FG_GEODESY_HXX
// $Log$
// Revision 1.4 1999/01/27 04:46:15 curt
// Portability tweaks by Bernie Bright.
//
// Revision 1.3 1998/10/18 01:17:11 curt
// Point3D tweaks.
//
// Revision 1.2 1998/10/16 23:36:37 curt
// c++-ifying.
//
// Revision 1.1 1998/10/16 19:30:42 curt
// Renamed .c -> .h so we can start adding c++ supporting routines.
//
// Revision 1.4 1998/07/08 14:40:08 curt
// polar3d.[ch] renamed to polar3d.[ch]xx, vector.[ch] renamed to vector.[ch]xx
// Updated fg_geodesy comments to reflect that routines expect and produce
// meters.
//
// Revision 1.3 1998/04/21 17:03:48 curt
// Prepairing for C++ integration.
//
// Revision 1.2 1998/01/22 02:59:38 curt
// Changed #ifdef FILE_H to #ifdef _FILE_H
//
// Revision 1.1 1997/07/31 23:13:14 curt
// Initial revision.
//