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Abstract
I/O
Examples
Particulars
Required Reading
Version
Index_Entries

Abstract


   CSPICE_CYLREC converts cylindrical coordinates to rectangular
   (Cartesian) coordinates.

I/O


   Given:

      r      the value(s) describing the distance of the point of
             interest from z axis.

             [1,n] = size(r); double = class(r)

      lonc   the value(s) describing the cylindrical angle of the point of
             interest from the XZ plane measured in radians.

             [1,n] = size(lonc); double = class(lonc)

      z      the value(s) describing the height of the point above
             the XY plane.

             [1,n] = size(z); double = class(z)

   the call:

      rectan = cspice_cylrec( r, lonc, z)

   returns:

      rectan   the array(s) containing the rectangular coordinates of the
               position or set of positions

               [3,n] = size(rectan); double = class(rectan)

               The argument 'rectan' returns in the same units associated
               with 'r' and 'z'.

               'rectan' returns with the same vectorization measure (N) as
               'r', 'lonc', and 'z'

Examples


   Any numerical results shown for this example may differ between
   platforms as the results depend on the SPICE kernels used as input
   and the machine specific arithmetic implementation.

   Example (1):

      %
      % Load an SPK, leapseconds, and PCK kernel set.
      %
      cspice_furnsh( 'standard.tm' )

      %
      % Create a vector of scalar times.
      %
      et = [0:2]*2.*cspice_spd;

      %
      % Retrieve the position of the moon seen from earth at 'et'
      % in the J2000 frame without aberration correction.
      %
      [pos, et] = cspice_spkpos( 'MOON', et, 'J2000', 'NONE', 'EARTH' );

      %
      % Convert the array of position vectors 'pos' to cylindrical
      % coordinates.
      %
      [r, lonc, z] = cspice_reccyl(pos);

      %
      % Convert the cylindrical to rectangular.
      %
      [rectan] = cspice_cylrec(r, lonc, z);

      %
      % Calculate the relative error against the original position
      % vectors.
      %
      (rectan-pos) ./ pos

      end

   MATLAB outputs:

      1.0e-13 *

      0.00199609007208                  0  -0.25513381329527
     -0.00218237675815                  0  -0.00153127196389
                     0                  0                  0

       The relative error between the original array of position vectors
       and those resulting from the coordinate conversions
       has magnitude on the order of 10^(-13).  A numerical
       demonstration of equality.

   Example (2):

      %
      % Define six sets of cylindrical coordinates, 'lonc' expressed
      % in degrees - converted to radians by use of cspice_rpd.
      %
      r     = [ 1.,  1.,   1.,   1.,   0.,  0. ];
      lonc  = [ 0., 90., 180., 180., 180., 33. ] * cspice_rpd;
      z     = [ 0.,  0.,   1.,  -1.,   1.,  0. ];

      %
      % ...convert the cylindrical coordinates to rectangular coordinates
      %
      [rec] = cspice_cylrec(r, lonc, z);

      %
      % ...convert angular measure to degrees.
      %
      lonc = lonc * cspice_dpr;

      disp('     r         lonc        z           x         y           z   ')
      disp('  --------   --------   --------   --------   --------   --------')

      %
      % Create an array of values for output.
      %
      output = [ r; lonc; z; rec(1,:); rec(2,:); rec(3,:) ];

      txt = sprintf( '%10.4f %10.4f %10.4f %10.4f %10.4f %10.4f\n', output );
      disp( txt )

      %
      % It's always good form to unload kernels after use,
      % particularly in MATLAB due to data persistence.
      %
      cspice_kclear

   MATLAB outputs:

        r         lonc        z           x         y           z
     --------   --------   --------   --------   --------   --------
       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   180.0000     1.0000    -1.0000     0.0000     1.0000
       1.0000   180.0000    -1.0000    -1.0000     0.0000    -1.0000
       0.0000   180.0000     1.0000    -0.0000     0.0000     1.0000
       0.0000    33.0000     0.0000     0.0000     0.0000     0.0000

Particulars


   None.

Required Reading


   For important details concerning this module's function, please refer to
   the CSPICE routine cylrec_c.

   MICE.REQ

Version


   -Mice Version 1.0.1, 30-OCT-2014, EDW (JPL)

       Edited I/O section to conform to NAIF standard for Mice documentation.

   -Mice Version 1.0.0, 22-NOV-2005, EDW (JPL)

Index_Entries


   cylindrical to rectangular


Wed Apr  5 18:00:30 2017