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pckw02_c

Table of contents
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

   pckw02_c ( PCK, write type 2 segment ) 

   void pckw02_c ( SpiceInt           handle,
                   SpiceInt           clssid,
                   ConstSpiceChar   * frame,
                   SpiceDouble        first,
                   SpiceDouble        last,
                   ConstSpiceChar   * segid,
                   SpiceDouble        intlen,
                   SpiceInt           n,
                   SpiceInt           polydg,
                   SpiceDouble        cdata  [],
                   SpiceDouble        btime      )

Abstract

   Write a type 2 segment to a PCK binary file given the file handle,
   frame class ID, base frame, time range covered by the segment, and
   the Chebyshev polynomial coefficients.

Required_Reading

   DAF
   FRAMES
   NAIF_IDS
   PCK
   SPC

Keywords

   PCK


Brief_I/O

   VARIABLE  I/O  DESCRIPTION
   --------  ---  --------------------------------------------------
   handle     I   Handle of binary PCK file open for writing.
   clssid     I   Frame class ID of body-fixed frame.
   frame      I   Name of base reference frame.
   first      I   Start time of interval covered by segment.
   last       I   End time of interval covered by segment.
   segid      I   Segment identifier.
   intlen     I   Length of time covered by logical record.
   n          I   Number of logical records in segment.
   polydg     I   Chebyshev polynomial degree.
   cdata      I   Array of Chebyshev coefficients.
   btime      I   Begin time of first logical record.

Detailed_Input

   handle      is the DAF handle of an PCK file to which a type 2
               segment is to be added. The PCK file must be open
               for writing.

   clssid      is the frame class ID of a body-fixed reference frame
               whose orientation is described by the segment to be
               created.

   frame       is the NAIF name for a reference frame relative to
               which the orientation information for the frame
               designated by `clssid' is specified. The frame
               designated by `frame' is called the "base frame."

   first,
   last        are, respectively, the start and stop times of
               the time interval over which the segment defines
               the orientation of clssid.

   segid       is the segment identifier. A PCK segment
               identifier may contain up to 40 characters.

   intlen      Length of time, in seconds, covered by each set of
               Chebyshev polynomial coefficients (each logical
               record). Each set of Chebyshev coefficients must
               cover this fixed time interval, `intlen'.

   n           is the number of sets of Chebyshev polynomial
               coefficients (number of logical records)
               to be stored in the segment. There is one set
               of Chebyshev coefficients for each time interval.

   polydg      Degree of each set of Chebyshev polynomials.

   cdata       Array containing all the sets of Chebyshev
               polynomial coefficients to be contained in the
               segment of the PCK file. The coefficients are
               stored in cdata in order as follows:

                  the (degree + 1) coefficients for the first
                  Euler angle of the first logical record

                  the coefficients for the second Euler angle

                  the coefficients for the third Euler angle

                  the coefficients for the first Euler angle for
                  the second logical record, ...

                  and so on.

   btime       Begin time (seconds past J2000 TDB) of first set
               of Chebyshev polynomial coefficients (first
               logical record).

Detailed_Output

   None.

Parameters

   None.

Exceptions

   1)  If the number of sets of coefficients is not positive, the
       error SPICE(NUMCOEFFSNOTPOS) is signaled by a routine in the
       call tree of this routine.

   2)  If the interval length is not positive, the error
       SPICE(INTLENNOTPOS) is signaled by a routine in the call tree
       of this routine.

   3)  If the integer code for the reference frame is not recognized,
       the error SPICE(INVALIDREFFRAME) is signaled by a routine in
       the call tree of this routine.

   4)  If segment stop time is not greater then the begin time, the
       error SPICE(BADDESCRTIMES) is signaled by a routine in the
       call tree of this routine.

   5)  If the time of the first record is not greater than or equal
       to the descriptor begin time, the error SPICE(BADDESCRTIMES)
       is signaled by a routine in the call tree of this routine.

   6)  If the end time of the last record is not greater than or
       equal to the descriptor end time, the error
       SPICE(BADDESCRTIMES) is signaled by a routine in the call tree
       of this routine.

   7)  If any of the `frame' or `segid' input string pointers is
       null, the error SPICE(NULLPOINTER) is signaled.

   8)  If any of the `frame' or `segid' input strings has zero
       length, the error SPICE(EMPTYSTRING) is signaled.

Files

   A new type 2 PCK segment is written to the PCK file attached
   to HANDLE.

Particulars

   This routine writes an PCK type 2 data segment to the designated
   PCK file, according to the format described in the PCK Required
   Reading.

   Each segment can contain data for only one body-fixed frame and base
   reference frame. The Chebyshev polynomial degree and length of time
   covered by each logical record are also fixed. However, an
   arbitrary number of logical records of Chebyshev polynomial
   coefficients can be written in each segment. Minimizing the number
   of segments in a PCK file will help optimize how the SPICE system
   accesses the file.

Examples

   The numerical results shown for this example may differ across
   platforms. The results depend on the SPICE kernels used as
   input, the compiler and supporting libraries, and the machine
   specific arithmetic implementation.

   1) Suppose that you have sets of Chebyshev polynomial
      coefficients in an array pertaining to the orientation of
      the Moon body-fixed frame with the frame class ID 301
      relative to the J2000 reference frame, and want
      to put these into a type 2 segment PCK file. The following
      example could be used to add one new type 2 segment. To add
      multiple segments, put the call to pckw02_c in a loop.


      Example code begins here.


      /.
         Program pckw02_ex1
      ./
      #include "SpiceUsr.h"

      int main( )
      {

         /.
         Local parameters
         ./
         #define FNAME        "pckw02_ex1.bpc"
         #define BODY         301
         #define POLYDG       9
         #define SZCDAT       60

         /.
         Local variables
         ./
         SpiceChar          * ifname;
         SpiceChar          * segid;

         SpiceDouble          btime;
         SpiceDouble          first;
         SpiceDouble          intlen;
         SpiceDouble          last;

         SpiceInt             handle;
         SpiceInt             n;
         SpiceInt             nresvc;

         /.
         Set the input data: RA/DEC/W coefficients,
         begin time for the first record, start/end times
         for the segment, length of the time covered by
         each record, and number of logical records.

         `cdata' contains the ra/dec/w coefficients: first the
         the polydeg + 1 for the RA first record, then the
         polydeg + 1 for the DEC first record, then the
         polydeg +1 for W first record, then the polydeg + 1
         for the RA second record, and so on.
         ./
         SpiceDouble          cdata  [SZCDAT] = {
                       -5.4242086033301107e-002, -5.2241405162792561e-005,
                        8.9751456289930307e-005, -1.5288696963234620e-005,
                        1.3218870864581395e-006,  5.9822156790328180e-007,
                       -6.5967702052551211e-008, -9.9084309118396298e-009,
                        4.9276055963541578e-010,  1.1612267413829385e-010,
                        0.42498898565916610,      1.3999219324235620e-004,
                       -1.8855140511098865e-005, -2.1964684808526649e-006,
                        1.4229817868138752e-006, -1.6991716166847001e-007,
                       -3.4824688140649506e-008,  2.9208428745895990e-009,
                        4.4217757657060300e-010, -3.9211207055305402e-012,
                        2565.0633504619473,       0.92003769451305328,
                       -8.0503797901914501e-005,  1.1960860244433900e-005,
                       -1.2237900518372542e-006, -5.3651349407824562e-007,
                        6.0843372260403005e-008,  9.0211287487688797e-009,
                       -4.6460429330339309e-010, -1.0446918704281774e-010,
                       -5.3839796353225056e-002,  4.3378021974424991e-004,
                        4.8130091384819459e-005, -1.2283066272873327e-005,
                       -5.4099296265403208e-006, -4.4237368347319652e-007,
                        1.3004982445546169e-007,  1.9017128275284284e-008,
                       -7.0368223839477803e-011, -1.7119414526133175e-010,
                        0.42507987850614548,     -7.1844899448557937e-005,
                       -5.1052122872412865e-005, -8.9810401387721321e-006,
                       -1.4611718567948972e-007,  4.0883847771062547e-007,
                        4.6812854485029333e-008, -4.5698075960784951e-009,
                       -9.8679875320349531e-010, -7.9392503778178240e-011,
                        2566.9029069934054,       0.91952244801740568,
                       -6.0426151041179828e-005,  1.0850559330577959e-005,
                        5.1756033678137497e-006,  4.2127585555214782e-007,
                       -1.1774737441872970e-007, -1.7397191490163833e-008,
                        5.8908810244396165e-012,  1.4594279337955166e-010 };

         first  =   -43200.0;
         last   =  1339200.0;
         btime  =  first;
         intlen =   691200.0;
         n      =  2;

         /.
         Open a new PCK file.  For simplicity, we will not
         reserve any space for the comment area, so the
         number of reserved comment characters is zero.
         The variable `ifname' is the internal file name.
         ./
         nresvc  =  0;
         ifname  =  "Test PCK/Created 04-SEP-2019";

         pckopn_c ( FNAME, ifname, nresvc, &handle );

         /.
         Create a segment identifier.
         ./
         segid = "MY_SAMPLE_PCK_TYPE_2_SEGMENT";

         /.
         Write the segment.
         ./
         pckw02_c ( handle, BODY, "J2000", first, last, segid,
                    intlen, n,    POLYDG,  cdata, btime       );

         /.
         Close the file.
         ./
         pckcls_c ( handle );

         return ( 0 );
      }


      When this program is executed, no output is presented on
      screen. After run completion, a new PCK type 2 exists in
      the output directory.

Restrictions

   None.

Literature_References

   None.

Author_and_Institution

   N.J. Bachman        (JPL)
   J. Diaz del Rio     (ODC Space)
   K.S. Zukor          (JPL)

Version

   -CSPICE Version 1.0.1, 04-AUG-2021 (JDR)

       Edited the header to comply with NAIF standard. Added
       complete code examples based on existing fragment.

   -CSPICE Version 1.0.0, 16-DEC-2016 (NJB) (KSZ)

Index_Entries

   write PCK type_2 data segment
Fri Dec 31 18:41:10 2021