spkw03_c

Index Page spkw03_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 spkw03_c ( SpiceInt                handle,
                       SpiceInt                body,
                       SpiceInt                center,
                       ConstSpiceChar        * frame,
                       SpiceDouble             first,
                       SpiceDouble             last,
                       ConstSpiceChar        * segid,
                       SpiceDouble             intlen,
                       SpiceInt                n,
                       SpiceInt                polydg,
                       ConstSpiceDouble        cdata [],
                       SpiceDouble             btime     )
#### Abstract
      Write a type 3 segment to an SPK file.
#### Required_Reading
       NAIF_IDS
       SPC
       SPK
#### Keywords
       EPHEMERIS
#### Brief_I/O
     Variable  I/O  Description
       --------  ---  --------------------------------------------------
       handle     I   Handle of SPK file open for writing.
       body       I   NAIF code for ephemeris object.
       center     I   NAIF code for the center of motion of the body.
       frame      I   Reference frame name.
       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 record.
       n          I   Number of records in segment.
       polydg     I   Chebyshev polynomial degree.
       cdata      I   Array of Chebyshev coefficients.
       btime      I   Begin time of first record.
#### Detailed_Input
       handle         DAF handle of an SPK file to which a type 3 segment
                      is to be added.  The SPK file must be open for
                      writing.

       body           NAIF integer code for an ephemeris object whose
                      state relative to another body is described by the
                      segment to be created.

       center         NAIF integer code for the center of motion of the
                      object identified by body.

       frame          NAIF name for a reference frame relative to which
                      the state information for body is specified.

       first,
       last           Start and stop times of the time interval over
                      which the segment defines the state of body.

       segid          Segment identifier.  An SPK 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 coefficents must
                      cover this fixed time interval, intlen.

       n              Number of sets of Chebyshev polynomial coefficients
                      for coordinates and their derivatives (number of
                      logical records) to be stored in the segment.
                      There is one set of Chebyshev coefficients for each
                      time period.

       polydg         Degree of each set of Chebyshev polynomials.

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

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

                         the coefficients for the second coordinate

                         the coefficients for the third coordinate

                         the coefficients for the derivative of the first
                         coordinate

                         the coefficients for the derivative of the
                         second coordinate

                         the coefficients for the derivative of the third
                         coordinate

                         the coefficients for the first coordinate 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
          SPICE(NUMCOEFFSNOTPOS) is signaled.

       2) If the interval length is not positive, SPICE(INTLENNOTPOS)
          is signaled.

       3) If the integer code for the reference frame is not recognized,
          SPICE(INVALIDREFFRAME) is signaled.

       4) If segment stop time is not greater then the begin time,
           SPICE(BADDESCRTIMES) is signaled.

       5) If the start time of the first record is not less than
          or equal to the descriptor begin time, SPICE(BADDESCRTIMES)
          is signaled.

       6) If the end time of the last record is not greater than
          or equal to the descriptor end time, SPICE(BADDESCRTIMES) is
          signaled.

       7) The error SPICE(EMPTYSTRING) is signaled if either input
          string does not contain at least one character, since the
          input strings cannot be converted to a Fortran-style string
          in this case.

       8) The error SPICE(NULLPOINTER) is signaled if either input string
          pointer is null.
#### Files
       A new type 3 SPK segment is written to the SPK file attached
       to handle.
#### Particulars
       This routine writes an SPK type 3 data segment to the designated
       SPK file, according to the format described in the SPK Required
       Reading.

       Each segment can contain data for only one target, central body,
       and 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 an SPK file will help optimize how the SPICE
       system accesses the file.
#### Examples
       Suppose that you have sets of Chebyshev polynomial coefficients
       in an array cdata pertaining to the position of the moon (NAIF ID
       = 301), relative to the Earth-moon barycenter (NAIF ID = 3), in
       the J2000 reference frame, and want to put these into a type 2
       segment in an existing SPK file.  The following code could be used
       to add one new type 2 segment.  To add multiple segments, put the
       call to SPKW02 in a loop.

          #include "SpiceUsr.h"
               .
               .
               .

          /.
          First open the SPK file and get a handle for it.
          ./
          spkopa_c ( spknam, &handle );

          /.
          Create a segment identifier.
          ./
          segid = "MY_SAMPLE_SPK_TYPE_3_SEGMENT";

          /.
          Write the segment.
          ./
          spkw03_c ( handle, 301,    3,      "J2000",
                     first,  last,   segid,  intlen,
                     n,      polydg, cdata,  btime   );

          /.
          Close the file.
          ./
          spkcls_c ( handle );
#### Restrictions
       None.
#### Literature_References
       None.
#### Author_and_Institution
       N.J. Bachman  (JPL)
       K.S. Zukor    (JPL)
#### Version
       -CSPICE Version 1.0.0, 08-MAR-2002 (EDW)

          Corrected section header typo: Example to Examples.

       -CSPICE Version 1.0.0, 23-JUN-1999 (NJB) (KSZ)
#### Index_Entries
       write spk type_3 data segment
#### Link to routine spkw03_c source file spkw03_c.c

    Thu Apr 16 08:59:16 2009