latrec_c

Index Page latrec_c
A B C D E F G H I J K L M N O P Q R S T U V W X
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
#### Link to routine latrec_c source file latrec_c.c

    Thu Apr 16 08:58:28 2009