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latrec_c
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Procedure
Abstract
Required_Reading
Keywords
Brief_I/O
Detailed_Input
Detailed_Output
Parameters
Exceptions
Files
Particulars
Examples
Restrictions
Literature_References
Author_and_Institution
Version
Index_Entries

Procedure

   void latrec_c ( SpiceDouble    radius,
                   SpiceDouble    longitude,
                   SpiceDouble    latitude,
                   SpiceDouble    rectan[3] )

Abstract

   Convert from latitudinal coordinates to rectangular coordinates.

Required_Reading

   None.

Keywords

   CONVERSION,  COORDINATES


Brief_I/O

   VARIABLE  I/O  DESCRIPTION
   --------  ---  --------------------------------------------------
   radius     I   Distance of a point from the origin.
   longitude  I   Longitude of point in radians.
   latitude   I   Latitude of point in radians.
   rectan     O   Rectangular coordinates of the point.

Detailed_Input

   radius     Distance of a point from the origin.
 
   longitude  Longitude of the input point.  This is the angle between
              the prime meridian and the meridian containing `rectan'.
              The direction of increasing longitude is from the +X axis
              towards the +Y axis.
 
              Longitude is measured in radians.  On input, the range 
              of longitude is unrestricted.

   latitude   Latitude of the input point. This is the angle from
              the XY plane of the ray from the origin through the
              point.

              Latitude is measured in radians. On input, the range of
              latitude is unrestricted.

Detailed_Output

   rectan     The rectangular coordinates of the input point.
              `rectan' is a 3 vector.

              The units associated with `rectan' are those
              associated with the input radius.

Parameters

   None.

Exceptions

   Error free.

Files

   None.

Particulars

   This routine returns the rectangular coordinates of a point
   whose position is input in latitudinal coordinates.

   Latitudinal coordinates are defined by a distance from a central
   reference point, an angle from a reference meridian, and an angle
   above the equator of a sphere centered at the central reference
   point.

Examples

   Below are two tables.

   Listed in the first table (under r, longitude and latitude ) are
   latitudinal coordinate triples that approximately represent
   points whose rectangular coordinates are taken from the set
   {-1, 0, 1}.  (Angular quantities are given in degrees.)

   The results of the code fragment

      /.
      Use the CSPICE routine rpd_c() to convert the angular
      quantities to radians
      ./
      latitude  *= rpd_c();
      longitude *= rpd_c();

      latrec_c ( r, longitude, latitude, rectan );


   are listed in the second parallel table under rectan[0], rectan[1],
   and rectan[2].


    r       longitude  latitude      rectan[0]  rectan[1] rectan[2].
   ----------------------------      -------------------------------
    0.0000    0.0000    0.0000         0.0000     0.0000   0.0000
    1.0000    0.0000    0.0000         1.0000     0.0000   0.0000
    1.0000   90.0000    0.0000         0.0000     1.0000   0.0000
    1.0000    0.0000   90.0000         0.0000     0.0000   1.0000
    1.0000  180.0000    0.0000        -1.0000     0.0000   0.0000
    1.0000  -90.0000    0.0000         0.0000    -1.0000   0.0000
    1.0000    0.0000  -90.0000         0.0000     0.0000  -1.0000
    1.4142   45.0000    0.0000         1.0000     1.0000   0.0000
    1.4142    0.0000   45.0000         1.0000     0.0000   1.0000
    1.4142   90.0000   45.0000         0.0000     1.0000   1.0000
    1.7320   45.0000   35.2643         1.0000     1.0000   1.0000

Restrictions

   None.

Literature_References

   None.

Author_and_Institution

   C.H. Acton      (JPL)
   N.J. Bachman    (JPL)
   E.D. Wright     (JPL)
   W.L. Taber      (JPL)

Version

   -CSPICE Version 1.0.1, 29-JUL-2003 (NJB) (CHA)

       Various header corrections were made.

   -CSPICE Version 1.0.0, 16-APR-1999 (EDW)
     

Index_Entries

   latitudinal to rectangular coordinates
Wed Apr  5 17:54:38 2017