spkcov_c

Index Page spkcov_c
A B C D E F G H I J K L M N O P Q R S T U V W X
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
       void spkcov_c ( ConstSpiceChar  * spk,
                       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
       --------  ---  --------------------------------------------------
       spk        I   Name of SPK file.
       idcode     I   ID code of ephemeris object.
       cover      O   Window giving coverage in `spk' for `idcode'.
#### Detailed_Input
       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.
#### Detailed_Output
       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'.
#### Parameters
       None.
#### Exceptions
       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 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.
#### 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
       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 );
             }
#### 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)
#### Version
       -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
#### Link to routine spkcov_c source file spkcov_c.c

    Thu Apr 16 08:59:12 2009