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#include "sofa.h"
int iauEform ( int n, double *a, double *f )
/*
** - - - - - - - - -
** i a u E f o r m
** - - - - - - - - -
**
** Earth reference ellipsoids.
**
** This function is part of the International Astronomical Union's
** SOFA (Standards of Fundamental Astronomy) software collection.
**
** Status: canonical.
**
** Given:
** n int ellipsoid identifier (Note 1)
**
** Returned:
** a double equatorial radius (meters, Note 2)
** f double flattening (Note 2)
**
** Returned (function value):
** int status: 0 = OK
** -1 = illegal identifier (Note 3)
**
** Notes:
**
** 1) The identifier n is a number that specifies the choice of
** reference ellipsoid. The following are supported:
**
** n ellipsoid
**
** 1 WGS84
** 2 GRS80
** 3 WGS72
**
** The n value has no significance outside the SOFA software. For
** convenience, symbols WGS84 etc. are defined in sofam.h.
**
** 2) The ellipsoid parameters are returned in the form of equatorial
** radius in meters (a) and flattening (f). The latter is a number
** around 0.00335, i.e. around 1/298.
**
** 3) For the case where an unsupported n value is supplied, zero a and
** f are returned, as well as error status.
**
** References:
**
** Department of Defense World Geodetic System 1984, National
** Imagery and Mapping Agency Technical Report 8350.2, Third
** Edition, p3-2.
**
** Moritz, H., Bull. Geodesique 66-2, 187 (1992).
**
** The Department of Defense World Geodetic System 1972, World
** Geodetic System Committee, May 1974.
**
** Explanatory Supplement to the Astronomical Almanac,
** P. Kenneth Seidelmann (ed), University Science Books (1992),
** p220.
**
** This revision: 2013 June 18
**
** SOFA release 2020-07-21
**
** Copyright (C) 2020 IAU SOFA Board. See notes at end.
*/
{
/* Look up a and f for the specified reference ellipsoid. */
switch ( n ) {
case WGS84:
*a = 6378137.0;
*f = 1.0 / 298.257223563;
break;
case GRS80:
*a = 6378137.0;
*f = 1.0 / 298.257222101;
break;
case WGS72:
*a = 6378135.0;
*f = 1.0 / 298.26;
break;
default:
/* Invalid identifier. */
*a = 0.0;
*f = 0.0;
return -1;
}
/* OK status. */
return 0;
/*----------------------------------------------------------------------
**
** Copyright (C) 2020
** Standards Of Fundamental Astronomy Board
** of the International Astronomical Union.
**
** =====================
** SOFA Software License
** =====================
**
** NOTICE TO USER:
**
** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
** CONDITIONS WHICH APPLY TO ITS USE.
**
** 1. The Software is owned by the IAU SOFA Board ("SOFA").
**
** 2. Permission is granted to anyone to use the SOFA software for any
** purpose, including commercial applications, free of charge and
** without payment of royalties, subject to the conditions and
** restrictions listed below.
**
** 3. You (the user) may copy and distribute SOFA source code to others,
** and use and adapt its code and algorithms in your own software,
** on a world-wide, royalty-free basis. That portion of your
** distribution that does not consist of intact and unchanged copies
** of SOFA source code files is a "derived work" that must comply
** with the following requirements:
**
** a) Your work shall be marked or carry a statement that it
** (i) uses routines and computations derived by you from
** software provided by SOFA under license to you; and
** (ii) does not itself constitute software provided by and/or
** endorsed by SOFA.
**
** b) The source code of your derived work must contain descriptions
** of how the derived work is based upon, contains and/or differs
** from the original SOFA software.
**
** c) The names of all routines in your derived work shall not
** include the prefix "iau" or "sofa" or trivial modifications
** thereof such as changes of case.
**
** d) The origin of the SOFA components of your derived work must
** not be misrepresented; you must not claim that you wrote the
** original software, nor file a patent application for SOFA
** software or algorithms embedded in the SOFA software.
**
** e) These requirements must be reproduced intact in any source
** distribution and shall apply to anyone to whom you have
** granted a further right to modify the source code of your
** derived work.
**
** Note that, as originally distributed, the SOFA software is
** intended to be a definitive implementation of the IAU standards,
** and consequently third-party modifications are discouraged. All
** variations, no matter how minor, must be explicitly marked as
** such, as explained above.
**
** 4. You shall not cause the SOFA software to be brought into
** disrepute, either by misuse, or use for inappropriate tasks, or
** by inappropriate modification.
**
** 5. The SOFA software is provided "as is" and SOFA makes no warranty
** as to its use or performance. SOFA does not and cannot warrant
** the performance or results which the user may obtain by using the
** SOFA software. SOFA makes no warranties, express or implied, as
** to non-infringement of third party rights, merchantability, or
** fitness for any particular purpose. In no event will SOFA be
** liable to the user for any consequential, incidental, or special
** damages, including any lost profits or lost savings, even if a
** SOFA representative has been advised of such damages, or for any
** claim by any third party.
**
** 6. The provision of any version of the SOFA software under the terms
** and conditions specified herein does not imply that future
** versions will also be made available under the same terms and
** conditions.
*
** In any published work or commercial product which uses the SOFA
** software directly, acknowledgement (see www.iausofa.org) is
** appreciated.
**
** Correspondence concerning SOFA software should be addressed as
** follows:
**
** By email: sofa@ukho.gov.uk
** By post: IAU SOFA Center
** HM Nautical Almanac Office
** UK Hydrographic Office
** Admiralty Way, Taunton
** Somerset, TA1 2DN
** United Kingdom
**
**--------------------------------------------------------------------*/
}