source: branches/FACT++_part_filenames/pal/palGeoc.c@ 19365

Last change on this file since 19365 was 18347, checked in by tbretz, 9 years ago
File size: 2.3 KB
Line 
1/*
2*+
3* Name:
4* palGeoc
5
6* Purpose:
7* Convert geodetic position to geocentric
8
9* Language:
10* Starlink ANSI C
11
12* Type of Module:
13* Library routine
14
15* Invocation:
16* void palGeoc( double p, double h, double * r, double *z );
17
18* Arguments:
19* p = double (Given)
20* latitude (radians)
21* h = double (Given)
22* height above reference spheroid (geodetic, metres)
23* r = double * (Returned)
24* distance from Earth axis (AU)
25* z = double * (Returned)
26* distance from plane of Earth equator (AU)
27
28* Description:
29* Convert geodetic position to geocentric.
30
31* Authors:
32* PTW: Patrick T. Wallace
33* TIMJ: Tim Jenness (JAC, Hawaii)
34* {enter_new_authors_here}
35
36* Notes:
37* - Geocentric latitude can be obtained by evaluating atan2(z,r)
38* - Uses WGS84 reference ellipsoid and calls eraGd2gc
39
40* History:
41* 2012-03-01 (TIMJ):
42* Initial version moved from palOne2One
43* Adapted with permission from the Fortran SLALIB library.
44* {enter_further_changes_here}
45
46* Copyright:
47* Copyright (C) 2004 Patrick T. Wallace
48* Copyright (C) 2012 Science and Technology Facilities Council.
49* All Rights Reserved.
50
51* Licence:
52* This program is free software: you can redistribute it and/or
53* modify it under the terms of the GNU Lesser General Public
54* License as published by the Free Software Foundation, either
55* version 3 of the License, or (at your option) any later
56* version.
57*
58* This program is distributed in the hope that it will be useful,
59* but WITHOUT ANY WARRANTY; without even the implied warranty of
60* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
61* GNU Lesser General Public License for more details.
62*
63* You should have received a copy of the GNU Lesser General
64* License along with this program. If not, see
65* <http://www.gnu.org/licenses/>.
66
67* Bugs:
68* {note_any_bugs_here}
69*-
70*/
71
72#include "pal.h"
73#include "pal1sofa.h"
74
75void palGeoc ( double p, double h, double *r, double *z ) {
76 double xyz[3];
77 const double elong = 0.0; /* Use zero longitude */
78 const double AU = 1.49597870E11;
79 /* WGS84 looks to be the closest match */
80 eraGd2gc( ERFA_WGS84, elong, p, h, xyz );
81 *r = xyz[0] / (AU * cos(elong) );
82 *z = xyz[2] / AU;
83}
Note: See TracBrowser for help on using the repository browser.