cspice_dskrb2 |
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## AbstractCSPICE_DSKRB2 determine range bounds for a DSK plate set. For important details concerning this module's function, please refer to the CSPICE routine dskrb2_c. ## I/OGiven: vrtces is an array of coordinates of the vertices. The Ith vertex occupies elements [0:2,I-1] of this array. plates is an array representing the triangular plates of a shape model. The elements of `plates' are vertex indices; vertex indices are 1-based. The vertex indices of the Ith plate occupy elements [0:2,I-1] of this array. corsys is an integer parameter identifying the coordinate system in which the bounds are to be computed. The bounds apply to the third coordinate in each system: Latitudinal: radius Planetodetic: altitude Rectangular: Z corpar is a array of parameters associated with the coordinate system. Currently the only supported system that has associated parameters is the planetodetic system. For planetodetic coordinates, corpar[0] is the equatorial radius corpar[1] is the flattening coefficient. Let `re' and `rp' represent, respectively, the equatorial and polar radii of the reference ellipsoid of the system. Then corpar[1] = ( re - rp ) / re the call: ## ExamplesAny 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 segment. PRO DSKW02_T ;; ;; IcyUser globally defines DSK parameters. ;; For more information, please see DSKIcyUser.m and ;; DSKIcyUser02.m. ;; @IcyUser 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 endif ;; ;; 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() end 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 end 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 ] end else: message, 'Icy(BUG)' endcase ;; ;; Compute plate model radius bounds. ;; print, 'Computing ' + cornam[corsys-1] +' bounds of plate set...' ## ParticularsUsers planning to create DSK files should consider whether the SPICE DSK creation utility MKDSK may be suitable for their needs. This routine supports use of the DSK type 2 segment writer cspice_dskw02 by computing bounds on the range of the third coordinates of the input plate set. ## Required ReadingICY.REQ DAS.REQ DSK.REQ ## Version-Icy Version 1.0.0, 14-DEC-2016, ML (JPL), EDW (JPL) ## Index_Entriescompute range bounds for type 2 dsk segment |

Wed Apr 5 17:58:00 2017