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Index Page spkcov_c

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Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input | Detailed_Output Parameters Exceptions Files Particulars Examples | Restrictions Literature_References Author_and_Institution Version Index_Entries

#### Procedure

       spkcov_c ( SPK coverage )

       void spkcov_c ( ConstSpiceChar  * spkfnm,
                       SpiceInt          idcode,
                       SpiceCell       * cover   )

#### Abstract

       Find the coverage window for a specified ephemeris object in a
       specified SPK file.

#### Required_Reading

       CELLS
       DAF
       SPK
       TIME
       WINDOWS

#### Keywords

       EPHEMERIS
       TIME
       UTILITY

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       spkfnm     I   Name of SPK file.
       idcode     I   ID code of ephemeris object.
       cover     I-O  Window giving coverage in `spkfnm' for `idcode'.

#### Detailed_Input

       spkfnm      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 SPICE 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 `spkfnm'.

                   If `cover' contains no data on input, its size and
                   cardinality still must be initialized.

                   `cover' must be declared as a double precision SpiceCell.

                   CSPICE provides the following macro, which declares and
                   initializes the cell

                      SPICEDOUBLE_CELL        ( cover, COVERSZ );

                   where COVERSZ is the maximum capacity of `cover'.

#### Detailed_Output

       cover       is a SPICE 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 `spkfnm', 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'.

#### Parameters

       None.

#### Exceptions

       1)  If the input file has transfer format, the error
           SPICE(INVALIDFORMAT) is signaled by a routine in the call tree
           of this routine.

       2)  If the input file is not a transfer file but has architecture
           other than DAF, the error SPICE(INVALIDARCHTYPE) is signaled
           by a routine in the call tree of this routine.

       3)  If the input file is a binary DAF file of type other than SPK,
           the error SPICE(INVALIDFILETYPE) is signaled by a routine in
           the call tree of this routine.

       4)  If the SPK file cannot be opened or read, an error is signaled
           by a routine in the call tree of this routine. The output
           window will not be modified.

       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', an error is signaled by a routine
           in the call tree of this routine.

       6)  If the `spkfnm' input string pointer is null, the error
           SPICE(NULLPOINTER) is signaled.

       7)  If the `spkfnm' input string has zero length, the error
           SPICE(EMPTYSTRING) is signaled.

       8)  If the `cover' cell argument has a type other than
           SpiceDouble, the error SPICE(TYPEMISMATCH) is signaled.

#### Files

       This routine reads an SPK file.

#### Particulars

       This routine provides an API via which applications can determine
       the coverage a specified SPK file provides for a specified
       ephemeris object.

#### Examples

       The numerical results shown for these examples 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 combined usage of spkcov_c and the
          related SPK utility spkobj_c.

          Display the coverage for each object in a specified SPK file.
          Find the set of objects in the file; for each object, find
          and display the coverage.

          Example code begins here.

          /.
             Program spkcov_ex1
          ./
          #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               spkfnm  [ 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_c 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, spkfnm    );

             /.
             Find the set of objects in the SPK file.
             ./
             spkobj_c ( spkfnm, &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 ( spkfnm, 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 %d\n", (int)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:  %d\n"
                            "Start:     %s\n",
                            (int)j,
                            timstr            );

                   timout_c ( e,
                              "YYYY MON DD HR:MN:SC.### (TDB) ::TDB",
                              TIMLEN,
                              timstr                                  );
                   printf ( "Stop:      %s\n", timstr );

                }

             }
             return ( 0 );
          }

          When this program was executed on a Mac/Intel/cc/64-bit
          platform, using the LSK file named naif0012.tls and the SPK
          file named mar097.bsp, the output was:

          Name of leapseconds kernel > naif0012.tls
          Name of SPK file           > mar097.bsp
          ========================================
          Coverage for object 3

          Interval:  0
          Start:     1900 JAN 04 00:00:41.184 (TDB)
          Stop:      2100 JAN 01 00:01:07.183 (TDB)
          ========================================
          Coverage for object 4

          Interval:  0
          Start:     1900 JAN 04 00:00:41.184 (TDB)
          Stop:      2100 JAN 01 00:01:07.183 (TDB)
          ========================================
          Coverage for object 10

          Interval:  0
          Start:     1900 JAN 04 00:00:41.184 (TDB)
          Stop:      2100 JAN 01 00:01:07.183 (TDB)
          ========================================
          Coverage for object 399

          Interval:  0
          Start:     1900 JAN 04 00:00:41.184 (TDB)
          Stop:      2100 JAN 01 00:01:07.183 (TDB)
          ========================================
          Coverage for object 401

          Interval:  0
          Start:     1900 JAN 04 00:00:41.184 (TDB)
          Stop:      2100 JAN 01 00:01:07.183 (TDB)
          ========================================
          Coverage for object 402

          Interval:  0
          Start:     1900 JAN 04 00:00:41.184 (TDB)
          Stop:      2100 JAN 01 00:01:07.183 (TDB)
          ========================================
          Coverage for object 499

          Interval:  0
          Start:     1900 JAN 04 00:00:41.184 (TDB)
          Stop:      2100 JAN 01 00:01:07.183 (TDB)

       2) Find the coverage for the object designated by `idcode'
          provided by the set of SPK files loaded via a metakernel.

          Use the meta-kernel shown below to load the required SPICE
          kernels.

             KPL/MK

             File: spkcov_ex2.tm

             This meta-kernel is intended to support operation of SPICE
             example programs. The kernels shown here should not be
             assumed to contain adequate or correct versions of data
             required by SPICE-based user applications.

             In order for an application to use this meta-kernel, the
             kernels referenced here must be present in the user's
             current working directory.

             The names and contents of the kernels referenced
             by this meta-kernel are as follows:

                File name                        Contents
                ---------                        --------
                de430.bsp                        Planetary ephemeris
                mar097.bsp                       Mars satellite ephemeris
                naif0011.tls                     Leapseconds

             \begindata

                KERNELS_TO_LOAD = ( 'de430.bsp',
                                    'mar097.bsp',
                                    'naif0011.tls' )

             \begintext

             End of meta-kernel

          Example code begins here.

          /.
             Program spkcov_ex2
          ./
          #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 %d\n", (int)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:  %d\n"
                         "Start:     %s\n",
                         (int)i,
                         timstr            );

                timout_c ( e,
                           "YYYY MON DD HR:MN:SC.### (TDB) ::TDB",
                           TIMLEN,
                           timstr                                  );
                printf ( "Stop:      %s\n", timstr );

             }
             return ( 0 );
          }

          When this program was executed on a Mac/Intel/cc/64-bit
          platform, using the meta-kernel named spkcov_ex2.tm provided
          above to find the coverage window for the Earth using its ID
          code, "399", the output was:

          Name of metakernel > spkcov_ex2.tm
          Enter ID code      > 399

          Coverage for object 399

          Interval:  0
          Start:     1549 DEC 31 00:00:00.000 (TDB)
          Stop:      2650 JAN 25 00:00:00.000 (TDB)

#### Restrictions

       1)  If an error occurs while this routine is updating the window
           `cover', the window may be corrupted.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)
       E.D. Wright         (JPL)

#### Version

       -CSPICE Version 1.1.0, 25-AUG-2021 (JDR)

           Changed input argument name "spk" to "spkfnm" for consistency with other
           routines.

           Edited the header to comply with NAIF standard. Added examples' solution
           and meta-kernel for example #2. Corrected short error message in entries
           #2 and #3 in -Exceptions section and added entry #8.

           Extended description of argument "cover" in -Detailed_Input to include
           type and preferred declaration method.

       -CSPICE Version 1.0.3, 14-JUN-2016 (EDW)

           Edit to example program to use "%d" with explicit casts
           to int for printing SpiceInts with printf.

       -CSPICE Version 1.0.2, 01-JUL-2014 (NJB)

           Added new index entries.

       -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)

#### Index_Entries

       get coverage window for spk_object
       get coverage start and stop time for spk_object
       get coverage start and stop time for ephemeris_object
       get coverage start and stop time for body

#### Link to routine spkcov_c source file spkcov_c.c

    Fri Dec 31 18:41:12 2021