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Required Reading


   CSPICE_DSKOPN opens a new DSK file, returning the handle
   of the opened file.

   For important details concerning this module's function, please refer to
   the CSPICE routine dskopn_c.



      fname    the name of the DSK file to open.

      ifname   the descriptive internal filename for the DSK.

      ncomch   the scalar integer number of characters to
               reserve for comments.

   the call:

      cspice_dskopn, fname, ifname, ncomch, handle


      handle   the file handle assigned to 'fname'.


   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.

   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.

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

      PRO DSKW02_T

         ;; IcyUser globally defines DSK parameters.
         ;; For more information, please see DSKIcyUser.m and
         ;; DSKIcyUser02.m.

         SPICETRUE = 1L
         NSEG = 3

         cornam = [ 'radius', 'Z-coordinate', 'Z-coordinate', 'altitude']

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

         if ( cspice_exists(dsk) ) then begin
            file_delete, dsk

         ;; Open input DSK for read access; find first segment.
         cspice_dasopr, indsk, inhan
         cspice_dlabfs, inhan, dladsc, found

         ;; Fetch vertices and plates from input DSK file.
         ;; Note that vertex and plate indices are 1-based.
         print, 'Reading input data...'

         cspice_dskv02, inhan, dladsc, 1, SPICE_DSK02_MAXVRT, vrtces
         cspice_dskp02, inhan, dladsc, 1, SPICE_DSK02_MAXPLT, plates

         print, 'Done.'

         ;; Set input array sizes required by cspice_dskmi2.
         voxpsz = SPICE_DSK02_MAXVXP
         voxlsz = SPICE_DSK02_MXNVLS
         worksz = SPICE_DSK02_MAXCEL
         spaisz = SPICE_DSK02_SPAISZ
         makvtl = SPICETRUE

         ;; Set fine and coarse voxel scales. (These usually
         ;; need to determined by experimentation.)
         finscl = 5.D
         corscl = 4

         ;; Open a new DSK file.
         cspice_dskopn, dsk, dsk, 0, handle

         for segno=1, NSEG do begin

            ;; Create spatial index. We won't generate a
            ;; vertex-plate mapping, so we set the flag
            ;; for creating this map to "false."
            print, 'Creating segment ', segno
            print, 'Creating spatial index...'

            cspice_dskmi2, vrtces, plates, finscl, corscl, $
                           worksz, voxpsz, voxlsz, makvtl, $
                           spaisz, spaixd, spaixi

            print, 'Done.'

            ;; 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.D * cspice_jyear()
            last  =  50.D * cspice_jyear()

            ;; Set the coordinate system and coordinate system
            ;; bounds based on the segment index.
            ;; Zero out the coordinate parameters to start.
            corpar = dblarr(SPICE_DSK_NSYPAR)

            case segno of

               1 : begin

                  ;; Use planetocentric latitudinal coordinates. Set
                  ;; the longitude and latitude bounds.
                  corsys = SPICE_DSK_LATSYS

                  mncor1 = -cspice_pi()
                  mxcor1 =  cspice_pi()
                  mncor2 = -cspice_halfpi()
                  mxcor2 =  cspice_halfpi()


               2 : begin

                  ;; 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 = -1.3D
                  mxcor1 =  1.31D
                  mncor2 = -1.21D
                  mxcor2 =  1.2D


               3 : begin

                  ;; Set the coordinate system to planetodetic.
                  corsys    = SPICE_DSK_PDTSYS

                  mncor1    = -cspice_pi()
                  mxcor1    =  cspice_pi()
                  mncor2    = -cspice_halfpi()
                  mxcor2    =  cspice_halfpi()

                  ;; 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.D0
                  rp        =  9.1D
                  f         = ( re - rp ) / re

                  corpar = [ re, f ]


               else: message, 'Icy(BUG)'


           ;; Compute plate model radius bounds.
           print, 'Computing ' + cornam[corsys-1] +' bounds of plate set...'

           cspice_dskrb2, vrtces, plates, corsys, corpar, mncor3, mxcor3

           print, 'Done.'

           ;; Write the segment to the file.
           print, 'Writing segment...'

           cspice_dskw02, handle, $
                          center, $
                          surfid, $
                          dclass, $
                          frame,  $
                          corsys, $
                          corpar, $
                          mncor1, $
                          mxcor1, $
                          mncor2, $
                          mxcor2, $
                          mncor3, $
                          mxcor3, $
                          first,  $
                          last,   $
                          vrtces, $
                          plates, $
                          spaixd, $


         ;; Close the input DSK.
         cspice_dskcls, handle, SPICETRUE
         cspice_dascls, inhan


   IDL outputs:

      Reading input data...
      Creating segment        1
      Creating spatial index...
      Computing radius bounds of plate set...
      Writing segment...
      Creating segment        2
      Creating spatial index...
      Computing Z-coordinate bounds of plate set...
      Writing segment...
      Creating segment        3
      Creating spatial index...
      Computing altitude bounds of plate set...
      Writing segment...      

      After run completion, A DSK exists in the output directory.


   A cspice_dskcls call should balance every cspice_dskopn

Required Reading



   -Icy Version 1.0.0, 14-DEC-2016, ML (JPL), EDW (JPL)


   open a new dsk file

Wed Apr  5 17:58:00 2017