recsph_c

Index Page recsph_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 recsph_c ( ConstSpiceDouble     rectan[3],
                       SpiceDouble        * r,
                       SpiceDouble        * colat,
                       SpiceDouble        * lon      )
#### Abstract
       Convert from rectangular coordinates to spherical coordinates.
#### Required_Reading
       None.
#### Keywords
       CONVERSION,  COORDINATES
#### Brief_I/O
       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       rectan     I   Rectangular coordinates of a point.
       r          O   Distance of the point from the origin.
       colat      O   Angle of the point from the positive Z-axis.
       lon        O   Longitude of the point in radians.
#### Detailed_Input
       rectan     The rectangular coordinates of a point.
#### Detailed_Output
       r          Distance of the point from the origin.

       colat      Angle between the point and the positive z-axis.

       lon        Longitude of the point in radians.  This is the angle
                  between the positive X-axis and the orthogonal
                  projection of the point onto the XY plane.  LONG
                  increases in the counterclockwise sense about the
                  positive Z-axis.  The range of LONG is:

                     -pi < LONG <= pi
#### Parameters
       None.
#### Exceptions
       Error free.
#### Files
       None.
#### Particulars
       This routine returns the spherical coordinates of a point
       whose position is input in rectangular coordinates.

       spherical coordinates are defined by a distance from a central
       reference point, an angle from a reference meridian, and an angle
       from the z-axis.
#### Examples
       Below are two tables.

       Listed in the first table (under X(1), X(2) and X(3) ) are a
       number of points whose rectangular coordinates are
       taken from the set {-1, 0, 1}.

       The result of the code fragment

            recsph_c ( X, r, colat, lon  )

            Use the CSPICE routine convrt_c to convert the angular
            quantities to degrees

            convrt_c ( colat, "RADIANS", "DEGREES", colat )
            convrt_c (  lon,  "RADIANS", "DEGREES", lon   )

       are listed to 4 decimal places in the second parallel table under
       r (radius), colat (co-latitude), and  lon  (longitude).

         X(1)       X(2)     X(3)        r         colat       lon
         --------------------------      ----------------------------
         0.0000     0.0000   0.0000      0.0000     0.0000     0.0000
         1.0000     0.0000   0.0000      1.0000    90.0000     0.0000
         0.0000     1.0000   0.0000      1.0000    90.0000    90.0000
         0.0000     0.0000   1.0000      1.0000     0.0000     0.0000
        -1.0000     0.0000   0.0000      1.0000    90.0000   180.0000
         0.0000    -1.0000   0.0000      1.0000    90.0000   -90.0000
         0.0000     0.0000  -1.0000      1.0000   180.0000     0.0000
         1.0000     1.0000   0.0000      1.4142    90.0000    45.0000
         1.0000     0.0000   1.0000      1.4142    45.0000     0.0000
         0.0000     1.0000   1.0000      1.4142    45.0000    90.0000
         1.0000     1.0000   1.0000      1.7320    54.7356    45.0000
#### Restrictions
       None.
#### Literature_References
       None.
#### Author_and_Institution
       W.L. Taber      (JPL)
       E.D. Wright     (JPL)
#### Version
       -CSPICE Version 1.1.1, 07-JAN-2002 (NJB) (EDW)

         Fixed description of lon in Brief_I/O and Detailed_I/O
         header sections.

       -CSPICE Version 1.1.0, 22-OCT-1998 (NJB)

          Made input coordinate array const.

       -CSPICE Version 1.0.0, 08-FEB-1998 (EDW)
#### Index_Entries
       rectangular to spherical coordinates
#### Link to routine recsph_c source file recsph_c.c

    Thu Apr 16 08:58:57 2009