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 2021-05-12 * * Copyright (C) 2021 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) 2021 * 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 * *----------------------------------------------------------------------- END