SUBROUTINE iau_GD2GCE ( A, F, ELONG, PHI, HEIGHT, XYZ, J )
*+
*  - - - - - - - - - - -
*   i a u _ G D 2 G C E
*  - - - - - - - - - - -
*
*  Transform geodetic coordinates to geocentric for a reference
*  ellipsoid of specified form.
*
*  This routine is part of the International Astronomical Union's
*  SOFA (Standards of Fundamental Astronomy) software collection.
*
*  Status:  support routine.
*
*  Given:
*     A         d     equatorial radius (Notes 1,4)
*     F         d     flattening (Notes 2,4)
*     ELONG     d     longitude (radians, east +ve)
*     PHI       d     latitude (geodetic, radians, Note 4)
*     HEIGHT    d     height above ellipsoid (geodetic, Notes 3,4)
*
*  Returned:
*     XYZ       d(3)  geocentric vector (Note 3)
*     J         i     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 J=-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 routine iau_GC2GDE.
*
*  6) The transformation for a standard ellipsoid (such as WGS84) can
*     more conveniently be performed by calling iau_GD2GC, which uses a
*     numerical code (1 for WGS84) 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.
*
*  This revision:  2009 November 2
*
*  SOFA release 2018-01-30
*
*  Copyright (C) 2018 IAU SOFA Board.  See notes at end.
*
*-----------------------------------------------------------------------

      IMPLICIT NONE

      DOUBLE PRECISION A, F, ELONG, PHI, HEIGHT, XYZ(3)
      INTEGER J

      DOUBLE PRECISION SP, CP, W, D, AC, AS, R

* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


*  Functions of geodetic latitude.
      SP = SIN(PHI)
      CP = COS(PHI)
      W = 1D0-F
      W = W*W
      D = CP*CP + W*SP*SP
      IF ( D .GT. 0D0 ) THEN
         AC = A / SQRT(D)
         AS = W * AC

*     Geocentric vector.
         R = ( AC + HEIGHT ) * CP
         XYZ(1) = R * COS(ELONG)
         XYZ(2) = R * SIN(ELONG)
         XYZ(3) = ( AS + HEIGHT ) * SP

*     Success.
         J = 0
      ELSE

*     Fail.
         J = -1
      END IF

*  Finished.

*+----------------------------------------------------------------------
*
*  Copyright (C) 2018
*  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
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*
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*
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*
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*
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*
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*
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*
*-----------------------------------------------------------------------

      END