Table of contents
CSPICE_SPKUEF unloads an ephemeris file from the kernel
system.
Given:
handle the integer handle assigned to the file upon loading.
help, handle
LONG = Scalar
the call:
cspice_spkuef, handle
removes from the kernel system all references to the SPK
kernel referred to by `handle'.
None.
Any numerical results shown for this example may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.
1) Load a planetary ephemeris SPK; then look up a series of
geometric states of the Earth relative to the solar system
barycenter, referenced to the J2000 frame.
Use the SPK kernel below to load the required ephemerides
for the Earth and the Earth Barycenter relative to the solar
system barycenter.
de405.bsp
Example code begins here.
PRO spkuef_ex1
;;
;; Local parameters.
;;
MAXITR = 5
ET0 = -315576000.0
STEP = 3600.0
ABCORR = 'NONE'
FRAME = 'J2000'
OBSRVR = 'SOLAR SYSTEM BARYCENTER'
SPK = 'de405.bsp'
TARGET = 'EARTH'
;;
;; Load the SPK file.
;;
cspice_spklef, SPK, handle
;;
;; Step through a series of epochs, looking up a state vector
;; at each one.
;;
for i=0, MAXITR - 1L do begin
et = ET0 + i*STEP
cspice_spkezr, TARGET, et, FRAME, ABCORR, OBSRVR, state, ltime
print
print, format='(A,F21.10)', 'et = ', et
print
print, format='(A,F21.10)', 'J2000 x-position (km): ', state[0]
print, format='(A,F21.10)', 'J2000 y-position (km): ', state[1]
print, format='(A,F21.10)', 'J2000 z-position (km): ', state[2]
print, format='(A,F21.10)', 'J2000 x-velocity (km/s):', state[3]
print, format='(A,F21.10)', 'J2000 y-velocity (km/s):', state[4]
print, format='(A,F21.10)', 'J2000 z-velocity (km/s):', state[5]
print
endfor
;;
;; Unload the SPK kernel. This isn't necessary in a stand-
;; alone program, but it's good practice in procedures
;; because it frees program and system resources.
;;
cspice_spkuef, handle
END
When this program was executed on a Mac/Intel/IDL8.x/64-bit
platform, the output was:
et = -315576000.0000000000
J2000 x-position (km): -26772058.9514643848
J2000 y-position (km): 132760135.1677220613
J2000 z-position (km): 57557579.2735445350
J2000 x-velocity (km/s): -29.7772753957
J2000 y-velocity (km/s): -5.0656884328
J2000 z-velocity (km/s): -2.1979102802
et = -315572416.0000000000
J2000 x-position (km): -26878773.3732022829
J2000 y-position (km): 132741944.0943545550
J2000 z-position (km): 57549686.5114355534
J2000 x-velocity (km/s): -29.7731803858
J2000 y-velocity (km/s): -5.0855796048
J2000 z-velocity (km/s): -2.2065325889
et = -315568800.0000000000
J2000 x-position (km): -26986425.6981768459
J2000 y-position (km): 132723518.3595090210
J2000 z-position (km): 57541691.9637668282
J2000 x-velocity (km/s): -29.7690319295
J2000 y-velocity (km/s): -5.1056448242
J2000 z-velocity (km/s): -2.2152302239
et = -315565184.0000000000
J2000 x-position (km): -27094062.9916883670
J2000 y-position (km): 132705020.0753098428
J2000 z-position (km): 57533665.9684742540
J2000 x-velocity (km/s): -29.7648665253
J2000 y-velocity (km/s): -5.1257064565
J2000 z-velocity (km/s): -2.2239261848
et = -315561600.0000000000
J2000 x-position (km): -27200732.8499865979
J2000 y-position (km): 132686613.9163857996
J2000 z-position (km): 57525679.9742503539
J2000 x-velocity (km/s): -29.7607212708
J2000 y-velocity (km/s): -5.1455869940
J2000 z-velocity (km/s): -2.2325435301
A file is removed from consideration by the readers by a call to
cspice_spkuef.
The file table entry corresponding to the file referenced by
`handle', is removed. Any segment table entry which came from the
specified file is also deleted.
If the file specified by `handle' is not currently loaded in the
SPK system, no action is taken.
Note: This routine, and all kernel file unload routines requiring
explicit file handle management has been superseded by
cspice_unload. Use cspice_unload to unload only those kernels
loaded with cspice_furnsh.
1) Unloading a file that has not been loaded is a no-op.
No error is signaled.
2) If the input argument `handle' is undefined, an error is
signaled by the IDL error handling system.
3) If the input argument `handle' is not of the expected type, or
it does not have the expected dimensions and size, an error is
signaled by the Icy interface.
The file referred to by `handle' is unloaded.
None.
ICY.REQ
SPK.REQ
None.
J. Diaz del Rio (ODC Space)
E.D. Wright (JPL)
-Icy Version 1.0.1, 10-AUG-2021 (JDR)
Edited the header to comply with NAIF standard. Added complete
code examples.
Added -Parameters, -Exceptions, -Files, -Restrictions,
-Literature_References and -Author_and_Institution sections, and
completed -Particulars section. Moved the note present in the -I/O
section to -Particulars.
Removed reference to the routine's corresponding CSPICE header from
-Abstract section.
Added argument's type and size information in the -I/O section.
-Icy Version 1.0.0, 16-JUN-2003 (EDW)
unload SPK ephemeris file
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