void spkcov_c ( ConstSpiceChar * spk,
SpiceInt idcode,
SpiceCell * cover )
Find the coverage window for a specified ephemeris object in a
specified SPK file.
CELLS
DAF
SPK
TIME
WINDOWS
EPHEMERIS
TIME
UTILITY
Variable I/O Description
-------- --- --------------------------------------------------
spk I Name of SPK file.
idcode I ID code of ephemeris object.
cover O Window giving coverage in `spk' for `idcode'.
spk is the name of an SPK file.
idcode is the integer ID code of an object for which
ephemeris data are expected to exist in the
specified SPK file.
cover is an initialized CSPICE window data structure.
`cover' optionally may contain coverage data on
input; on output, the data already present in
`cover' will be combined with coverage found for the
object designated by `idcode' in the file `spk'.
If `cover' contains no data on input, its size and
cardinality still must be initialized.
cover is a CSPICE window data structure which
represents the merged coverage for `idcode'. This is
the set of time intervals for which data for
`idcode' are present in the file `spk', merged with
the set of time intervals present in `cover' on
input. The merged coverage is represented as the
union of one or more disjoint time intervals. The
window `cover' contains the pairs of endpoints of
these intervals.
The interval endpoints contained in `cover' are
ephemeris times, expressed as seconds past J2000
TDB.
See the Examples section below for a complete
example program showing how to retrieve the
endpoints from `cover'.
None.
This routine provides an API via which applications can determine
the coverage a specified SPK file provides for a specified
ephemeris object.
1) Display the coverage for each object in a specified SPK file.
Find the set of objects in the file. Loop over the contents
of the ID code set: find the coverage for each item in the
set and display the coverage.
#include <stdio.h>
#include "SpiceUsr.h"
int main()
{
/.
Local parameters
./
#define FILSIZ 256
#define MAXIV 1000
#define WINSIZ ( 2 * MAXIV )
#define TIMLEN 51
#define MAXOBJ 1000
/.
Local variables
./
SPICEDOUBLE_CELL ( cover, WINSIZ );
SPICEINT_CELL ( ids, MAXOBJ );
SpiceChar lsk [ FILSIZ ];
SpiceChar spk [ FILSIZ ];
SpiceChar timstr [ TIMLEN ];
SpiceDouble b;
SpiceDouble e;
SpiceInt i;
SpiceInt j;
SpiceInt niv;
SpiceInt obj;
/.
Load a leapseconds kernel for output time conversion.
SPKCOV itself does not require a leapseconds kernel.
./
prompt_c ( "Name of leapseconds kernel > ", FILSIZ, lsk );
furnsh_c ( lsk );
/.
Get name of SPK file.
./
prompt_c ( "Name of SPK file > ", FILSIZ, spk );
/.
Find the set of objects in the SPK file.
./
spkobj_c ( spk, &ids );
/.
We want to display the coverage for each object. Loop over
the contents of the ID code set, find the coverage for
each item in the set, and display the coverage.
./
for ( i = 0; i < card_c( &ids ); i++ )
{
/.
Find the coverage window for the current object.
Empty the coverage window each time so we don't
include data for the previous object.
./
obj = SPICE_CELL_ELEM_I( &ids, i );
scard_c ( 0, &cover );
spkcov_c ( spk, obj, &cover );
/.
Get the number of intervals in the coverage window.
./
niv = wncard_c ( &cover );
/.
Display a simple banner.
./
printf ( "%s\n", "========================================" );
printf ( "Coverage for object %ld\n", obj );
/.
Convert the coverage interval start and stop times to TDB
calendar strings.
./
for ( j = 0; j < niv; j++ )
{
/.
Get the endpoints of the jth interval.
./
wnfetd_c ( &cover, j, &b, &e );
/.
Convert the endpoints to TDB calendar
format time strings and display them.
./
timout_c ( b,
"YYYY MON DD HR:MN:SC.### (TDB) ::TDB",
TIMLEN,
timstr );
printf ( "\n"
"Interval: %ld\n"
"Start: %s\n",
j,
timstr );
timout_c ( e,
"YYYY MON DD HR:MN:SC.### (TDB) ::TDB",
TIMLEN,
timstr );
printf ( "Stop: %s\n", timstr );
}
}
return ( 0 );
}
2) Find the coverage for the object designated by `idcode'
provided by the set of SPK files loaded via a metakernel.
(The metakernel must also specify a leapseconds kernel.)
#include <stdio.h>
#include "SpiceUsr.h"
int main()
{
/.
Local parameters
./
#define FILSIZ 256
#define LNSIZE 81
#define MAXCOV 100000
#define WINSIZ ( 2 * MAXCOV )
#define TIMLEN 51
/.
Local variables
./
SPICEDOUBLE_CELL ( cover, WINSIZ );
SpiceBoolean found;
SpiceChar file [ FILSIZ ];
SpiceChar idch [ LNSIZE ];
SpiceChar meta [ FILSIZ ];
SpiceChar source [ FILSIZ ];
SpiceChar timstr [ TIMLEN ];
SpiceChar type [ LNSIZE ];
SpiceDouble b;
SpiceDouble e;
SpiceInt count;
SpiceInt handle;
SpiceInt i;
SpiceInt idcode;
SpiceInt niv;
/.
Prompt for the metakernel name; load the metakernel.
The metakernel lists the SPK files whose coverage
for `idcode' we'd like to determine. The metakernel
must also specify a leapseconds kernel.
./
prompt_c ( "Name of metakernel > ", FILSIZ, meta );
furnsh_c ( meta );
/.
Get the ID code of interest.
./
prompt_c ( "Enter ID code > ", LNSIZE, idch );
prsint_c ( idch, &idcode );
/.
Find out how many kernels are loaded. Loop over the
kernels: for each loaded SPK file, add its coverage
for `idcode', if any, to the coverage window.
./
ktotal_c ( "SPK", &count );
for ( i = 0; i < count; i++ )
{
kdata_c ( i, "SPK", FILSIZ, LNSIZE, FILSIZ,
file, type, source, &handle, &found );
spkcov_c ( file, idcode, &cover );
}
/.
Display results.
Get the number of intervals in the coverage window.
./
niv = wncard_c ( &cover );
/.
Display a simple banner.
./
printf ( "\nCoverage for object %ld\n", idcode );
/.
Convert the coverage interval start and stop times to TDB
calendar strings.
./
for ( i = 0; i < niv; i++ )
{
/.
Get the endpoints of the ith interval.
./
wnfetd_c ( &cover, i, &b, &e );
/.
Convert the endpoints to TDB calendar
format time strings and display them.
./
timout_c ( b,
"YYYY MON DD HR:MN:SC.### (TDB) ::TDB",
TIMLEN,
timstr );
printf ( "\n"
"Interval: %ld\n"
"Start: %s\n",
i,
timstr );
timout_c ( e,
"YYYY MON DD HR:MN:SC.### (TDB) ::TDB",
TIMLEN,
timstr );
printf ( "Stop: %s\n", timstr );
}
return ( 0 );
}
1) If an error occurs while this routine is updating the window
`cover', the window may be corrupted.
1) If the input file has transfer format, the error
SPICE(INVALIDFORMAT) is signaled.
2) If the input file is not a transfer file but has architecture
other than DAF, the the error SPICE(BADARCHTYPE) is signaled.
3) If the input file is a binary DAF file of type other than
SPK, the error SPICE(BADFILETYPE) is signaled.
4) If the SPK file cannot be opened or read, the error will
be diagnosed by routines called by this routine. The output
window will not be modified.
routines called by this routine.
5) If the size of the output window argument `cover' is
insufficient to contain the actual number of intervals in the
coverage window for `idcode', the error will be diagnosed by
routines called by this routine.
6) The error SPICE(EMPTYSTRING) is signaled if the input
string `spk' does not contain at least one character, since the
input string cannot be converted to a Fortran-style string in
this case.
7) The error SPICE(NULLPOINTER) is signaled if the input string
pointer `spk' is null.
This routine reads an SPK file.
N.J. Bachman (JPL)
None.
-CSPICE Version 1.0.1, 30-NOV-2007 (NJB)
Corrected bug in first example program in header:
program now empties result window prior to collecting
data for each object. Deleted declaration of unused
constant NAMLEN. Updated examples to use wncard_c
rather than card_c.
-CSPICE Version 1.0.0, 30-DEC-2004 (NJB)
get coverage window for spk object
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