Procedure

     CKGR04 ( C-kernel, get record, type 04 )

     SUBROUTINE CKGR04 ( HANDLE, DESCR, RECNO, RECORD )

Abstract

     Return a specified pointing record from a CK type 04 segment.
     The segment is identified by a CK file handle and segment
     descriptor.

Required_Reading

     CK
     DAF

Keywords

     POINTING

Declarations

     IMPLICIT NONE

     INCLUDE               'ckparam.inc'

     INTEGER               HANDLE
     DOUBLE PRECISION      DESCR   ( * )
     INTEGER               RECNO
     DOUBLE PRECISION      RECORD  ( * )

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     HANDLE     I   The handle of the file containing the segment.
     DESCR      I   The segment descriptor.
     RECNO      I   The number of the pointing record to be returned.
     RECORD     O   The pointing record.

Detailed_Input

     HANDLE   is the handle of the binary CK file containing the
              desired segment. The file should have been opened
              for read or write access, either by CKLPF, DAFOPR,
              or DAFOPW.

     DESCR    is the packed descriptor of the data type 4 segment.

     RECNO    is the number of the pointing record to be returned
              from the data type 4 segment.

Detailed_Output

     RECORD   is the pointing record indexed by RECNO in the
              segment. The contents of the record are as follows:

              ---------------------------------------------------
              | The midpoint of the approximation interval      |
              ---------------------------------------------------
              | The radius of the approximation interval        |
              ---------------------------------------------------
              | Number of coefficients for q0                   |
              ---------------------------------------------------
              | Number of coefficients for q1                   |
              ---------------------------------------------------
              | Number of coefficients for q2                   |
              ---------------------------------------------------
              | Number of coefficients for q3                   |
              ---------------------------------------------------
              | Number of coefficients for AV1                  |
              ---------------------------------------------------
              | Number of coefficients for AV2                  |
              ---------------------------------------------------
              | Number of coefficients for AV3                  |
              ---------------------------------------------------
              | q0 Cheby coefficients                           |
              ---------------------------------------------------
              | q1 Cheby coefficients                           |
              ---------------------------------------------------
              | q2 Cheby coefficients                           |
              ---------------------------------------------------
              | q3 Cheby coefficients                           |
              ---------------------------------------------------
              | AV1 Cheby coefficients (optional)               |
              ---------------------------------------------------
              | AV2 Cheby coefficients (optional)               |
              ---------------------------------------------------
              | AV3 Cheby coefficients (optional)               |
              ---------------------------------------------------

Parameters

     See 'ckparam.inc'.

Exceptions

     1)  If the segment is not of data type 4, the error
         SPICE(CKWRONGDATATYPE) is signaled.

     2)  If RECNO is less than one or greater than the number of
         records in the specified segment, the error
         SPICE(CKNONEXISTREC) is signaled.

     3)  If the specified handle does not belong to any DAF file that
         is currently known to be open, an error is signaled by a
         routine in the call tree of this routine.

     4)  If DESCR is not a valid descriptor of a segment in the CK
         file specified by HANDLE, the results of this routine are
         unpredictable.

Files

     The file specified by HANDLE should be open for read or
     write access.

Particulars

     For a detailed description of the structure of a type 4 segment,
     see the CK required reading.

     This is a utility routine that may be used to read the individual
     pointing records that make up a type 4 segment. It is normally
     used in conjunction with CKNR04, which gives the number of
     pointing records stored in a segment.

Examples

     Suppose that DATA.BC is a CK file that contains segments of
     data type 4. Then the following code fragment extracts the
     data packets contained in the segment.

     C
     C     CK parameters include file.
     C
           INCLUDE               'ckparam.inc'

     C
     C     Local variables.
     C
           DOUBLE PRECISION      DCD    ( 2 )
           DOUBLE PRECISION      DESCR  ( 5 )
           DOUBLE PRECISION      PKTDAT ( CK4RSZ )

           INTEGER               AVFLAG
           INTEGER               HANDLE
           INTEGER               I
           INTEGER               ICD    ( 6 )
           INTEGER               K
           INTEGER               LASTAD
           INTEGER               NCOEF  ( QAVSIZ )
           INTEGER               NREC

           LOGICAL               FOUND
     C
     C     First load the file. (The file may also be opened by using
     C     CKLPF.)
     C
           CALL DAFOPR ( 'DATA.BC', HANDLE )
     C
     C     Begin forward search. Find the first array.
     C
           CALL DAFBFS ( HANDLE )
           CALL DAFFNA ( FOUND  )
     C
     C     Get segment descriptor.
     C
           CALL DAFGS ( DESCR )
     C
     C     Unpack the segment descriptor into its double precision
     C     and integer components.
     C
           CALL DAFUS ( DESCR, 2, 6, DCD, ICD )

           IF ( ICD( 3 ) .EQ. 4 ) THEN
     C
     C        How many records does this segment contain?
     C
              CALL CKNR04 ( HANDLE, DESCR, NREC )

              DO I = 1, NREC
     C
     C           Get the data records stored in the segment.
     C
                 CALL CKGR04 ( HANDLE, DESCR, I, PKTDAT )
     C
     C           Print data packet contents. Print coverage interval
     C           midpoint & radii first.
     C
                 WRITE (2,*) PKTDAT (1)
                 WRITE (2,*) PKTDAT (2)
     C
     C           Decode numbers of coefficients.
     C
                 CALL ZZCK4D2I ( PKTDAT(3), QAVSIZ, CK4PCD, NCOEF )
     C
     C           Print number of coefficients for Q0, Q1, Q2 and Q3.
     C
                 WRITE (2,FMT='(I2,6X,I2)') NCOEF( 1 ), NCOEF( 2 )
                 WRITE (2,FMT='(I2,6X,I2)') NCOEF( 3 ), NCOEF( 4 )
     C
     C           Print number coefficients for AV1, AV2 and AV3.
     C
                 WRITE (2,FMT='(I2,6X,I2)') NCOEF( 5 ), NCOEF( 6 )
                 WRITE (2,FMT='(I2,6X,I2)') NCOEF( 7 )
     C
     C           Print Cheby coefficients.
     C
                 LASTAD = 0

                 DO K = 1, QAVSIZ
                    LASTAD = LASTAD + NCOEF( K )
                 END DO

                 DO K = 4, LASTAD + 4
                    WRITE (2,*) PKTDAT (K)
                 END DO

              END DO

           END IF

Restrictions

     1)  The binary CK file containing the segment whose descriptor
         was passed to this routine must be opened for read or write
         access by either CKLPF, DAFOPR, or DAFOPW.

Literature_References

     None.

Author_and_Institution

     J. Diaz del Rio    (ODC Space)
     B.V. Semenov       (JPL)
     Y.K. Zaiko         (JPL)

Version

    SPICELIB Version 1.0.2, 26-OCT-2021 (JDR)

        Edited the header to comply with NAIF standard.

    SPICELIB Version 1.0.1, 18-APR-2014 (BVS)

        Minor header edits.

    SPICELIB Version 1.0.0, 05-MAY-1999 (YKZ) (BVS)