Index Page spkw08_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 spkw08_c ( SpiceInt            handle,
                       SpiceInt            body,
                       SpiceInt            center,
                       ConstSpiceChar    * frame,
                       SpiceDouble         first,
                       SpiceDouble         last,
                       ConstSpiceChar    * segid,
                       SpiceInt            degree,
                       SpiceInt            n,
                       ConstSpiceDouble    states[][6],
                       SpiceDouble         epoch1,
                       SpiceDouble         step           )

#### Abstract

       Write a type 8 segment to an SPK file.

#### Required_Reading

       NAIF_IDS
       SPC
       SPK
       TIME

#### Keywords

       EPHEMERIS
       FILES

#### Brief_I/O

       Variable  I/O  Description
       --------  ---  --------------------------------------------------
       MAXDEG     P   Maximum degree of interpolating polynomials.
       TOLSCL     P   Scale factor used to compute time bound tolerance.
       handle     I   Handle of an SPK file open for writing.
       body       I   NAIF code for an ephemeris object.
       center     I   NAIF code for center of motion of 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.
       degree     I   Degree of interpolating polynomials.
       n          I   Number of states.
       states     I   Array of states.
       epoch1     I   Epoch of first state in states array.
       step       I   Time step separating epochs of states.
       MAXDEG     P   Maximum allowed degree of interpolating polynomial.

#### Detailed_Input

       handle         is the file handle of an SPK file that has been
                      opened for writing.

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

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

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

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

       segid          is the segment identifier.  An SPK segment
                      identifier may contain up to 40 characters.

       degree         is the degree of the Lagrange polynomials used to
                      interpolate the states.  All components of the
                      state vectors are interpolated by polynomials of
                      fixed degree.

       n              is the number of states in the input state vector
                      array.

       states         contains a time-ordered array of geometric states
                      ( x, y, z, dx/dt, dy/dt, dz/dt, in kilometers and
                      kilometers per second ) of body relative to center,
                      specified relative to frame.

       epoch1         is the epoch corresponding to the first state in
                      the state array.  Because extra states are needed
                      at the beginning and end of the segment in order
                      for the interpolation method to work, epoch1 will
                      normally precede first.

       step           is the time step separating the epochs of adjacent
                      states in the input state array.  step is specified
                      in seconds.

#### Detailed_Output

       None.  See $Particulars for a description of the effect of this
       routine.

#### Parameters

       The parameters below are declared in the Fortran include file
       spk08.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 interpolating
                         polynomial.

                         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 8 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 spkw08_c:

                            epoch1
                            step
                            n

                         The value of TOLSCL is 1.e-13.

#### Exceptions

       If any of the following exceptions occur, this routine will return
       without creating a new segment.

       1)  If FRAME is not a recognized name, the error
           SPICE(INVALIDREFFRAME) is signaled.

       2)  If the last non-blank character of SEGID occurs past index 40,
           the error SPICE(SEGIDTOOLONG) is signaled.

       3)  If SEGID contains any nonprintable characters, the error
           SPICE(NONPRINTABLECHARS) is signaled.

       4)  If DEGREE is not at least 1 or is greater than MAXDEG, the
           error SPICE(INVALIDDEGREE) is signaled.

       5)  If the number of states N is not at least DEGREE+1, the error
           SPICE(TOOFEWSTATES) will be signaled.

       6)  If FIRST is greater than LAST then the error
           SPICE(BADDESCRTIMES) will be signaled.

       7)  If STEP is non-positive, the error SPICE(INVALIDSTEPSIZE) will
           be signaled.

       8)  If the start time of the first record exceeds the descriptor
           begin time by more than a computed tolerance, or if the end time
           of the last record precedes the descriptor end time by more than
           a computed tolerance, the error SPICE(COVERAGEGAP) is signaled.
           See the Parameters section above for a description of the
           tolerance.

       9)  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.

       10) The error SPICE(NULLPOINTER) is signaled if either input string
           pointer is null.

#### Files

       A new type 8 SPK segment is written to the SPK file attached
       to handle.

#### Particulars

       This routine writes an SPK type 08 data segment to the open SPK
       file according to the format described in the type 08 section of
       the SPK Required Reading. The SPK file must have been opened with
       write access.

#### Examples

       Suppose that you have states and are prepared to produce
       a segment of type 08 in an SPK file.

       The following code fragment could be used to add the new segment
       to a previously opened SPK file attached to HANDLE. The file must
       have been opened with write access.

          #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_8_SEGMENT";

          /.
          Write the segment.
          ./
          spkw08_c (  handle,  body,    center,  frame,
                      first,   last,    segid,   degree,
                      n,       states,  epoch1,  step     );

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

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

       K.R. Gehringer (JPL)
       N.J. Bachman   (JPL)
       J.M. Lynch     (JPL)
       W.L. Taber     (JPL)

#### Version

       -CSPICE Version 2.0.0, 11-JAN-2014 (NJB)

           Relaxed test on relationship between the time bounds of the
           input record set (determined by `epoch1', `step', 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, 29-JUN-1999 (NJB)

#### Index_Entries

       write spk type_8 ephemeris data segment

#### Link to routine spkw08_c source file spkw08_c.c

    Wed Apr  5 17:54:44 2017