void spkw08_c ( SpiceInt handle,
ConstSpiceChar * frame,
ConstSpiceChar * segid,
SpiceDouble step )
Write a type 8 segment to an SPK file.
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.
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
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
n is the number of states in the input state vector
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
None. See $Particulars for a description of the effect of this
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
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
The value of TOLSCL is 1.e-13.
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
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
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.
A new type 8 SPK segment is written to the SPK file attached
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
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.
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 );
K.R. Gehringer (JPL)
N.J. Bachman (JPL)
J.M. Lynch (JPL)
W.L. Taber (JPL)
-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)
write spk type_8 ephemeris data segment