#include "erfa.h"
int eraGd2gce ( double a, double f, double elong, double phi,
double height, double xyz[3] )
/*
** - - - - - - - - - -
** e r a G d 2 g c e
** - - - - - - - - - -
**
** Transform geodetic coordinates to geocentric for a reference
** ellipsoid of specified form.
**
** Given:
** a double equatorial radius (Notes 1,4)
** f double flattening (Notes 2,4)
** elong double longitude (radians, east +ve)
** phi double latitude (geodetic, radians, Note 4)
** height double height above ellipsoid (geodetic, Notes 3,4)
**
** Returned:
** xyz double[3] geocentric vector (Note 3)
**
** Returned (function value):
** int status: 0 = OK
** -1 = illegal case (Note 4)
** Notes:
**
** 1) The equatorial radius, a, can be in any units, but meters is
** the conventional choice.
**
** 2) The flattening, f, is (for the Earth) a value around 0.00335,
** i.e. around 1/298.
**
** 3) The equatorial radius, a, and the height, height, must be
** given in the same units, and determine the units of the
** returned geocentric vector, xyz.
**
** 4) No validation is performed on individual arguments. The error
** status -1 protects against (unrealistic) cases that would lead
** to arithmetic exceptions. If an error occurs, xyz is unchanged.
**
** 5) The inverse transformation is performed in the function
** eraGc2gde.
**
** 6) The transformation for a standard ellipsoid (such as ERFA_WGS84) can
** more conveniently be performed by calling eraGd2gc, which uses a
** numerical code to identify the required a and f values.
**
** References:
**
** Green, R.M., Spherical Astronomy, Cambridge University Press,
** (1985) Section 4.5, p96.
**
** Explanatory Supplement to the Astronomical Almanac,
** P. Kenneth Seidelmann (ed), University Science Books (1992),
** Section 4.22, p202.
**
** Copyright (C) 2013-2014, NumFOCUS Foundation.
** Derived, with permission, from the SOFA library. See notes at end of file.
*/
{
double sp, cp, w, d, ac, as, r;
/* Functions of geodetic latitude. */
sp = sin(phi);
cp = cos(phi);
w = 1.0 - f;
w = w * w;
d = cp*cp + w*sp*sp;
if ( d <= 0.0 ) return -1;
ac = a / sqrt(d);
as = w * ac;
/* Geocentric vector. */
r = (ac + height) * cp;
xyz[0] = r * cos(elong);
xyz[1] = r * sin(elong);
xyz[2] = (as + height) * sp;
/* Success. */
return 0;
}
/*----------------------------------------------------------------------
**
**
** Copyright (C) 2013-2014, NumFOCUS Foundation.
** All rights reserved.
**
** This library is derived, with permission, from the International
** Astronomical Union's "Standards of Fundamental Astronomy" library,
** available from http://www.iausofa.org.
**
** The ERFA version is intended to retain identical functionality to
** the SOFA library, but made distinct through different function and
** file names, as set out in the SOFA license conditions. The SOFA
** original has a role as a reference standard for the IAU and IERS,
** and consequently redistribution is permitted only in its unaltered
** state. The ERFA version is not subject to this restriction and
** therefore can be included in distributions which do not support the
** concept of "read only" software.
**
** Although the intent is to replicate the SOFA API (other than
** replacement of prefix names) and results (with the exception of
** bugs; any that are discovered will be fixed), SOFA is not
** responsible for any errors found in this version of the library.
**
** If you wish to acknowledge the SOFA heritage, please acknowledge
** that you are using a library derived from SOFA, rather than SOFA
** itself.
**
**
** TERMS AND CONDITIONS
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1 Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
**
** 2 Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
**
** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
** the International Astronomical Union nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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**
*/