Index of Functions: A B C D E F G H I J K L M N O P Q R S T U V W X
Index Page dskopn_c

Table of contents

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

       dskopn_c ( DSK, open new file )

       void dskopn_c ( ConstSpiceChar  * fname,
                       ConstSpiceChar  * ifname,
                       SpiceInt          ncomch,
                       SpiceInt       *  handle )

#### Abstract

       Open a new DSK file for subsequent write operations.

#### Required_Reading

       DAS
       DSK

#### Keywords

       DAS
       DSK
       FILES

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       fname      I   Name of a DSK file to be opened.
       ifname     I   Internal file name.
       ncomch     I   Number of comment characters to allocate.
       handle     O   Handle assigned to the opened DSK file.

#### Detailed_Input

       fname       is the name of a new DSK file to be created. The
                   file will be left opened for write access.

       ifname      is the internal file name for the new file. The name
                   may contain as many as 60 characters. All characters
                   of `ifname' should be printing characters (ASCII codes
                   32-126 decimal). This name should uniquely identify
                   the file.

       ncomch      is the number of comment characters to allocate.
                   Allocating comment characters at file creation time
                   may reduce the likelihood of having to expand the
                   comment area later.

#### Detailed_Output

       handle      is the file handle associated with the file. This
                   handle is used to identify the file in subsequent
                   calls to other DSK routines.

#### Parameters

       None.

#### Exceptions

       1)  If the input filename is blank, an error is signaled by a
           routine in the call tree of this routine. No file will be
           created.

       2)  If the specified file cannot be opened without exceeding the
           maximum allowed number of open DAS files, an error is signaled
           by a routine in the call tree of this routine. No file will be
           created.

       3)  If the file cannot be opened properly, an error is signaled by
           a routine in the call tree of this routine. No file will be
           created.

       4)  If the initial records in the file cannot be written, an error
           is signaled by a routine in the call tree of this routine. No
           file will be created.

       5)  If no logical units are available, an error is signaled by a
           routine in the call tree of this routine. No file will be
           created.

       6)  If the internal file name contains nonprinting characters
           (ASCII codes decimal 0-31 and 127-255), an error is signaled
           by a routine in the call tree of this routine. No file will be
           created.

       7)  If the number of comment characters allocated `ncomch' is
           negative, an error is signaled by a routine in the call
           tree of this routine. No file will be created.

       8)  If any of the `fname' or `ifname' input string pointers is
           null, the error SPICE(NULLPOINTER) is signaled.

       9)  If any of the `fname' or `ifname' input strings has zero
           length, the error SPICE(EMPTYSTRING) is signaled.

#### Files

       See argument FNAME.

#### Particulars

       DSK files are built using the DLA low-level format and
       the DAS architecture; DLA files are a specialized type of DAS
       file in which data are organized as a doubly linked list of
       segments. Each segment's data belong to contiguous components of
       character, double precision, and integer type.

       This routine creates a new DSK file and sets the type of the
       file to the mnemonic code passed to it.

       DSK files created by this routine have initialized file records.
       The ID word in a DSK file record has the form

          DAS/DSK

       where the characters following the slash are supplied by the
       caller of this routine.

#### Examples

       The numerical results shown for this example 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) Create a three-segment DSK file using plate model data for
          Phobos. Use latitudinal, rectangular, and planetodetic
          coordinates in the respective segments. This is not a
          realistic example, but it serves to demonstrate use of
          the supported coordinate systems.

          Use the DSK kernel below to provide, for simplicity, the
          input plate and vertex data. The selected input file has one
          segment.

             phobos_3_3.bds

          Example code begins here.

          /.
             Program dskopn_ex1

             Example program for dskw02_c, dskmi2_c, and dskrb2_c

             Create a three-segment DSK file using plate model data for
             Phobos. Use latitudinal, rectangular, and planetodetic
             coordinates in the respective segments.

             For simplicity, use an existing DSK file to provide the
             input plate and vertex data. The selected input file has one
             segment.

                Version 1.0.0 22-JAN-2016 (NJB)

          ./
          #include <stdio.h>
          #include "SpiceUsr.h"

          int main()
          {

             /.
             Local constants
             ./
             #define FILSIZ          256
             #define LNSIZE           81
             #define NCOR              4
             #define NSEG              3
             #define NAMLEN           21

             /.
             Local variables
             ./

             /.
             Below, we declare large arrays static to avoid stack
             overflow problems.
             ./

             SpiceBoolean            found;

             SpiceChar               cornam [ NCOR ][ NAMLEN ] =
                                     { "radius",
                                       "Z-coordinate",
                                       "Z-coordinate",
                                       "altitude" };

             SpiceChar             * dsk;
             SpiceChar             * frame;
             SpiceChar             * indsk;

             SpiceDLADescr           dladsc;

             SpiceDouble             corpar [ SPICE_DSK_NSYPAR ];
             SpiceDouble             f;
             SpiceDouble             finscl;
             SpiceDouble             first;
             SpiceDouble             last;
             SpiceDouble             mncor1;
             SpiceDouble             mncor2;
             SpiceDouble             mncor3;
             SpiceDouble             mxcor1;
             SpiceDouble             mxcor2;
             SpiceDouble             mxcor3;
             SpiceDouble             re;
             SpiceDouble             rp;

             /.
             Note: the values of SPICE_DSK02_MAXVRT and
             SPICE_DSK02_MAXPLT declared in SpiceDSK.h,
             integer spatial index dimension SPICE_DSK02_SPAISZ,
             and the workspace dimension SPICE_DSK02_MAXCEL
             are very large. Smaller buffers can be used for most
             applications.
             ./
             static SpiceDouble      spaixd [ SPICE_DSK02_SPADSZ ];
             static SpiceDouble      vrtces [ SPICE_DSK02_MAXVRT ][3];

             SpiceInt                center;
             SpiceInt                corscl;
             SpiceInt                corsys;
             SpiceInt                dclass;
             SpiceInt                handle;
             SpiceInt                i;
             SpiceInt                inhan;
             SpiceInt                np;
             SpiceInt                nv;
             static SpiceInt         plates [ SPICE_DSK02_MAXPLT ][3];
             SpiceInt                segno;
             static SpiceInt         spaixi [ SPICE_DSK02_SPAISZ ];
             SpiceInt                spaisz;
             SpiceInt                surfid;
             SpiceInt                voxpsz;
             SpiceInt                voxlsz;
             static SpiceInt         work   [ SPICE_DSK02_MAXCEL ][2];
             SpiceInt                worksz;

             /.
             Assign names of input and output DSK files.
             ./
             indsk = "phobos_3_3.bds";
             dsk   = "phobos_3_3_3seg.bds";

             /.
             Open input DSK for read access; find first segment.
             ./
             dasopr_c ( indsk, &inhan );
             dlabfs_c ( inhan, &dladsc, &found );

             /.
             Fetch vertices and plates from input DSK file.

             Note that vertex and plate indices are 1-based.
             ./
             printf ( "Reading input data...\n" );

             dskv02_c ( inhan, &dladsc, 1, SPICE_DSK02_MAXVRT,
                        &nv,   vrtces                           );
             dskp02_c ( inhan, &dladsc, 1, SPICE_DSK02_MAXPLT,
                        &np,   plates                           );

             printf ( "Done.\n" );

             /.
             Set input array sizes required by dskmi2_c.
             ./
             voxpsz = SPICE_DSK02_MAXVXP;
             voxlsz = SPICE_DSK02_MXNVLS;
             worksz = SPICE_DSK02_MAXCEL;
             spaisz = SPICE_DSK02_SPAISZ;

             /.
             Set fine and coarse voxel scales. (These usually
             need to determined by experimentation.)
             ./
             finscl = 5.0;
             corscl = 4;

             /.
             Open a new DSK file.
             ./
             dskopn_c ( dsk, dsk, 0, &handle );

             /.
             Create three segments and add them to the file.
             ./
             for ( segno = 1;  segno <= NSEG;  segno++ )
             {
                /.
                Create spatial index. We won't generate a
                vertex-plate mapping, so we set the flag
                for creating this map to "false."
                ./
                printf ( "Creating segment %d\n", (int)segno );
                printf ( "Creating spatial index...\n" );

                dskmi2_c ( nv,     vrtces,     np,     plates,
                           finscl, corscl,     worksz, voxpsz,
                           voxlsz, SPICEFALSE, spaisz, work,
                           spaixd, spaixi                    );

                printf ( "Done.\n" );

                /.
                Set up inputs describing segment attributes:

                - Central body: Phobos
                - Surface ID code: user's choice.
                  We use the segment number here.
                - Data class: general (arbitrary) shape
                - Body-fixed reference frame
                - Time coverage bounds (TBD)
                ./
                center = 401;
                surfid = segno;
                dclass = SPICE_DSK_GENCLS;
                frame  = "IAU_PHOBOS";

                first = -50 * jyear_c();
                last  =  50 * jyear_c();

                /.
                Set the coordinate system and coordinate system
                bounds based on the segment index.

                Zero out the coordinate parameters to start.
                ./
                for ( i = 0;  i < SPICE_DSK_NSYPAR;  i++ )
                {
                   corpar[i] = 0.0;
                }

                if ( segno == 1 )
                {
                   /.
                   Use planetocentric latitudinal coordinates. Set
                   the longitude and latitude bounds.
                   ./
                   corsys = SPICE_DSK_LATSYS;

                   mncor1 = -pi_c();
                   mxcor1 =  pi_c();
                   mncor2 = -pi_c()/2;
                   mxcor2 =  pi_c()/2;
                }
                else if ( segno == 2 )
                {

                   /.
                   Use rectangular coordinates. Set the
                   X and Y bounds.

                   The bounds shown here were derived from
                   the plate data. They lie slightly outside
                   of the range spanned by the plates.
                   ./
                   corsys = SPICE_DSK_RECSYS;

                   mncor1 = -1.3;
                   mxcor1 =  1.31;
                   mncor2 = -1.21;
                   mxcor2 =  1.2;
                }
                else
                {
                   /.
                   Set the coordinate system to planetodetic.
                   ./
                   corsys    = SPICE_DSK_PDTSYS;

                   mncor1    = -pi_c();
                   mxcor1    =  pi_c();
                   mncor2    = -pi_c()/2;
                   mxcor2    =  pi_c()/2;

                   /.
                   We'll use equatorial and polar radii from
                   pck00010.tpc. These normally would be fetched
                   at run time, but for simplicity, we'll use
                   hard-coded values.
                   ./
                   re        = 13.0;
                   rp        =  9.1;
                   f         = ( re - rp ) / re;

                   corpar[0] = re;
                   corpar[1] = f;
                }
                /.
                Compute plate model radius bounds.
                ./
                printf ( "Computing %s bounds of plate set...\n",
                         cornam[corsys-1]                        );

                dskrb2_c ( nv,     vrtces, np,      plates,
                           corsys, corpar, &mncor3, &mxcor3 );

                printf ( "Done.\n" );

                /.
                Write the segment to the file.
                ./
                printf ( "Writing segment...\n" );

                dskw02_c ( handle,
                           center, surfid, dclass, frame,  corsys,
                           corpar, mncor1, mxcor1, mncor2, mxcor2,
                           mncor3, mxcor3, first,  last,   nv,
                           vrtces, np,     plates, spaixd, spaixi );

                printf ( "Done.\n" );
             }

             /.
             Segregate the data records in the DSK file and
             close the file.
             ./
             printf ( "Segregating and closing DSK file...\n" );

             dskcls_c ( handle, SPICETRUE );

             printf ( "Done.\n" );

             return ( 0 );
          }

          When this program was executed on a Mac/Intel/cc/64-bit
          platform, the output was:

          Reading input data...
          Done.
          Creating segment 1
          Creating spatial index...
          Done.
          Computing radius bounds of plate set...
          Done.
          Writing segment...
          Done.
          Creating segment 2
          Creating spatial index...
          Done.
          Computing Z-coordinate bounds of plate set...
          Done.
          Writing segment...
          Done.
          Creating segment 3
          Creating spatial index...
          Done.
          Computing altitude bounds of plate set...
          Done.
          Writing segment...
          Done.
          Segregating and closing DSK file...
          Done.

          Note that after run completion, a new DSK exists in the output
          directory.

#### Restrictions

       None.

#### Literature_References

       None.

#### Author_and_Institution

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

#### Version

       -CSPICE Version 1.0.1, 09-JUL-2021 (JDR)

           Edited the header to comply with NAIF standard. Added
           complete code example based on example in dskmi2_c.

       -CSPICE Version 1.0.0, 23-JAN-2016 (NJB)

           Corrected spelling errors in comments.

           DSKLIB_C Version 1.0.0, 12-FEB-2010 (NJB)

#### Index_Entries

       open a new DSK file
       open a new DSK file with write access

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

    Fri Dec 31 18:41:05 2021