| spk14e_c |
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Table of contents
Procedurespk14e_c ( SPK, end a type 14 segment ) void spk14e_c ( SpiceInt handle ) AbstractEnd the type 14 SPK segment currently being written to the SPK file associated with `handle'. Required_ReadingNone. KeywordsSPK Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- handle I The handle of an SPK file open for writing. Detailed_Input
handle is the file handle of an SPK file that has been
opened for writing, and to which a type 14 segment is
being written.
Detailed_OutputNone. The type 14 segment in the SPK file associated with `handle' will be ended, making the addition of the data to the file permanent. See the -Particulars section for details about the structure of a type 14 SPK segment. ParametersNone. Exceptions
1) If there are no segments currently being written to the file
associated with `handle', an error is signaled by a routine in
the call tree of this routine.
2) If any file access error occurs, the error is signaled by a
routine in the call tree of this routine.
FilesSee the argument `handle'. Particulars
This routine ends a type 14 SPK segment which is being written to
the SPK file associated with `handle'. Ending the SPK segment is a
necessary step in the process of making the data a permanent part
of the SPK file.
This routine is one of a set of three routines for creating and
adding data to type 14 SPK segments. These routines are:
spk14b_c: Begin a type 14 SPK segment. This routine must be
called before any data may be added to a type 14
segment.
spk14a_c: Add data to a type 14 SPK segment. This routine may be
called any number of times after a call to spk14b_c to
add type 14 records to the SPK segment that was
started.
spk14e_c: End a type 14 SPK segment. This routine is called to
make the type 14 segment a permanent addition to the
SPK file. Once this routine is called, no further type
14 records may be added to the segment. A new segment
must be started.
A type 14 SPK segment consists of coefficient sets for fixed order
Chebyshev polynomials over consecutive time intervals, where the
time intervals need not all be of the same length. The Chebyshev
polynomials represent the position, X, Y, and Z coordinates, and
the velocities, dX/dt, dY/dt, and dZ/dt, of a body relative to a
center of motion.
The ephemeris data supplied to the type 14 SPK writer routines is
packed into an array as a sequence of logical records,
-----------------------------------------------------
| Record 1 | Record 2 | ... | Record N-1 | Record N |
-----------------------------------------------------
with each record has the following format.
------------------------------------------------
| the midpoint of the approximation interval |
------------------------------------------------
| the radius of the approximation interval |
------------------------------------------------
| chbdeg+1 coefficients for the X coordinate |
------------------------------------------------
| chbdeg+1 coefficients for the Y coordinate |
------------------------------------------------
| chbdeg+1 coefficients for the Z coordinate |
------------------------------------------------
| chbdeg+1 coefficients for the X velocity |
------------------------------------------------
| chbdeg+1 coefficients for the Y velocity |
------------------------------------------------
| chbdeg+1 coefficients for the Z velocity |
------------------------------------------------
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) This example demonstrates how to create an SPK type 14 kernel
containing only one segment, given a set of Chebyshev
coefficients and their associated epochs.
Example code begins here.
/.
Program spk14e_ex1
./
#include "SpiceUsr.h"
int main( )
{
/.
Define the segment identifier parameters.
./
#define SPK14 "spk14e_ex1.bsp"
#define REF "J2000"
#define BODY 3
#define CENTER 10
#define CHBDEG 2
#define NRECS 4
#define RECSIZ ( 2 + 6*(CHBDEG+1) )
/.
Local variables.
./
SpiceChar * ifname;
SpiceChar * segid;
SpiceDouble first;
SpiceDouble last;
SpiceInt handle;
SpiceInt ncomch;
/.
Define the epochs and coefficients.
./
SpiceDouble epochs [NRECS+1] = {
100.0, 200.0, 300.0, 400.0, 500.0 };
SpiceDouble recrds [NRECS][RECSIZ] = {
{150.0, 50.0,
1.0101, 1.0102, 1.0103,
1.0201, 1.0202, 1.0203,
1.0301, 1.0302, 1.0303,
1.0401, 1.0402, 1.0403,
1.0501, 1.0502, 1.0503,
1.0601, 1.0602, 1.0603},
{250.0, 50.0,
2.0101, 2.0102, 2.0103,
2.0201, 2.0202, 2.0203,
2.0301, 2.0302, 2.0303,
2.0401, 2.0402, 2.0403,
2.0501, 2.0502, 2.0503,
2.0601, 2.0602, 2.0603},
{350.0, 50.0,
3.0101, 3.0102, 3.0103,
3.0201, 3.0202, 3.0203,
3.0301, 3.0302, 3.0303,
3.0401, 3.0402, 3.0403,
3.0501, 3.0502, 3.0503,
3.0601, 3.0602, 3.0603},
{450.0, 50.0,
4.0101, 4.0102, 4.0103,
4.0201, 4.0202, 4.0203,
4.0301, 4.0302, 4.0303,
4.0401, 4.0402, 4.0403,
4.0501, 4.0502, 4.0503,
4.0601, 4.0602, 4.0603} };
/.
Set the start and end times of interval covered by
segment.
./
first = epochs[0];
last = epochs[NRECS];
/.
`ncomch' is the number of characters to reserve for the
kernel's comment area. This example doesn't write
comments, so set to zero.
./
ncomch = 0;
/.
Internal file name and segment ID.
./
ifname = "Type 14 SPK internal file name.";
segid = "SPK type 14 test segment";
/.
Open a new SPK file.
./
spkopn_c ( SPK14, ifname, ncomch, &handle );
/.
Begin the segment.
./
spk14b_c ( handle, segid, BODY, CENTER, REF, first, last, CHBDEG );
/.
Add the data to the segment all at once.
./
spk14a_c ( handle, NRECS, recrds, epochs );
/.
End the segment, making the segment a permanent addition
to the SPK file.
./
spk14e_c ( handle );
/.
Close the SPK file.
./
spkcls_c ( handle );
return ( 0 );
}
When this program is executed, no output is presented on
screen. After run completion, a new SPK type 14 exists in
the output directory.
Restrictions
1) The type 14 SPK segment being closed must have been started by
the routine spk14b_c, the routine which begins a type 14 SPK
segment.
Literature_ReferencesNone. Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) K.R. Gehringer (JPL) E.D. Wright (JPL) Version
-CSPICE Version 1.0.2, 27-AUG-2021 (JDR)
Edited the header to comply with NAIF standard. Added
complete example code from existing fragment.
Updated -Exceptions section. Removed reference to other routines
from -Abstract section (already in -Particulars).
-CSPICE Version 1.0.1, 16-JAN-2003 (EDW)
Trivial correction to the header.
-CSPICE Version 1.0.0, 29-JUL-1999 (NJB) (KRG)
Index_Entriesend a type_14 SPK segment |
Fri Dec 31 18:41:12 2021