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Abstract
I/O
Examples
Particulars
Required Reading
Version
Index_Entries

Abstract


   CSPICE_RECLAT converts rectangular (Cartesian) coordinates to
   latitudinal coordinates. All coordinates are expressed as
   double precision values.

I/O


   Given:

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

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

   the call:

      [radius, lon, lat] = cspice_reclat(rectan)

   returns:

      radius   the value(s) describing the distance of the position
               from the origin.

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

      lon      the value(s) describing the angle of the position from
               the XZ plane measured in radians.

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

      lat      the value(s) describing the angle of the position from the
               XY plane measured in radians.

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

               The argument 'radius' returns in the same units associated
               with 'rectan'.

               'radius', 'lon', and 'lat' return with
               the same vectorization measure, N, as 'rectan'.

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 latitudinal
      % coordinates.
      %
      [radius, longitude, latitude] = cspice_reclat(pos);

      %
      % Convert the cylindrical to rectangular.
      %
      [rectan] = cspice_latrec(radius, longitude, latitude);

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

    MATLAB outputs:

      1.0e-14 *

     -0.01996090072080  -0.05552320600838   0.63783453323816
      0.02182376758148                  0  -0.01531271963894
      0.01912147275010   0.01213804257114   0.02039513446643

   Example (2):

      %
      % Define eleven sets of rectangular coordinates.
      %
      rec = [ [ 0., 1., 0., 0., -1., 0., 0., 1., 1., 0., 1. ]; ...
              [ 0., 0., 1., 0., 0., -1., 0., 1., 0., 1., 1. ]; ...
              [ 0., 0., 0., 1., 0., 0., -1., 0., 1., 1., 1. ]    ];

      %
      % ...convert the rectangular coordinates to latitudinal coordinates
      %
      [radius, longitude, latitude] = cspice_reclat(rec);

      %
      % Convert 'longitude' and 'latitude' to degrees.
      %
      longitude = longitude * cspice_dpr;
      latitude  = latitude  * cspice_dpr;

      %
      % Output banner.
      %
      disp('   radius    longitude  latitude       x         y           z   ')
      disp('  --------   --------   --------   --------   --------   --------')

      %
      % Create an array of values for output.
      %
      output = [radius; longitude; latitude; 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:

      radius    longitude  latitude       x         y           z
     --------   --------   --------   --------   --------   --------
       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
       1.7321    45.0000    35.2644     1.0000     1.0000     1.0000

Particulars


   None.

Required Reading


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

   MICE.REQ

Version


   -Mice Version 1.0.1, 01-DEC-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


   rectangular to latitudinal coordinates


Wed Apr  5 18:00:34 2017