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
       --------  ---  --------------------------------------------------
       MAXDEG     P   Maximum degree of Chebyshev expansions.
       TOLSCL     P   Scale factor used to compute time bound tolerance.
       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.

                      The logical data records are stored contiguously:

                         +----------+
                         | Record 1 |
                         +----------+
                         | Record 2 |
                         +----------+
                             ...
                         +----------+
                         | Record N |
                         +----------+

                      The contents of an individual record are:

                         +--------------------------------------+
                         | Coeff set for X position component   |
                         +--------------------------------------+
                         | Coeff set for Y position component   |
                         +--------------------------------------+
                         | Coeff set for Z position component   |
                         +--------------------------------------+
                         | Coeff set for X velocity component   |
                         +--------------------------------------+
                         | Coeff set for Y velocity component   |
                         +--------------------------------------+
                         | Coeff set for Z velocity component   |
                         +--------------------------------------+

                     Each coefficient set has the structure:

                         +--------------------------------------+
                         | Coefficient of T_0                   |
                         +--------------------------------------+
                         | Coefficient of T_1                   |
                         +--------------------------------------+
                                           ...
                         +--------------------------------------+
                         | Coefficient of T_POLYDG              |
                         +--------------------------------------+

                      Where T_n represents the Chebyshev polynomial
                      of the first kind of degree n.

       btime          Begin time (seconds past J2000 TDB) of first set
                      of Chebyshev polynomial coefficients (first
                      logical record).
#### Detailed_Output
       None.
#### Parameters
       The parameters below are declared in the Fortran include file
       spk03.inc, which is part of the Fortran SPICE Toolkit (aka
       SPICELIB). The values of those parameters are used in CSPICE code
       generated by running f2c on SPICELIB source code. They are not
       directly referenced by code in this module.

          MAXDEG         is the maximum allowed degree of the input
                         Chebyshev expansions.

                         The value of MAXDEG is 27.

          TOLSCL         is a tolerance scale factor (also called a
                         "relative tolerance") used for time coverage bound
                         checking. TOLSCL is unitless. TOLSCL produces a
                         tolerance value via the formula

                            TOL = TOLSCL * max( abs(first), abs(last) )

                         where `first' and `last' are the coverage time
                         bounds of a type 3 segment, expressed as seconds
                         past J2000 TDB.

                         The resulting parameter TOL is used as a tolerance
                         for comparing the input segment descriptor time
                         bounds to the first and last epoch covered by the
                         sequence of time intervals defined by the inputs
                         to spkw03_c:

                            btime
                            intlen
                            n

                         The value of TOLSCL is 1.e-13.
#### 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 input degree `polydg' is less than 0 or greater than
           MAXDEG, the error will be diagnosed by a routine in the call
           tree of this routine.

       6)  If the last non-blank character of `segid' occurs past index 40,
           or if `segid' contains any nonprintable characters, the error will
           be diagnosed by a routine in the call tree of this routine.

       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 3
       segment in an existing SPK file. The following code could be used
       to add one new type 3 segment.  To add multiple segments, put the
       call to spkw03_c 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 2.0.0, 09-JAN-2014 (NJB)

           Relaxed test on relationship between the time bounds of the
           input record set (determined by `btime', `intlen', and `n') and
           the descriptor bounds `first' and `last'. Now the descriptor
           bounds may extend beyond the time bounds of the record set by a
           ratio computed using the parameter TOLSCL (see Parameters above
           for details). Added checks on input polynomial degree.

       -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

    Wed Apr  5 17:54:44 2017