| dskb02_c |
|
Table of contents
Procedure
dskb02_c ( DSK, fetch type 2 bookkeeping data )
void dskb02_c ( SpiceInt handle,
ConstSpiceDLADescr * dladsc,
SpiceInt * nv,
SpiceInt * np,
SpiceInt * nvxtot,
SpiceDouble vtxbds [3][2],
SpiceDouble * voxsiz,
SpiceDouble voxori [3],
SpiceInt vgrext [3],
SpiceInt * cgscal,
SpiceInt * vtxnpl,
SpiceInt * voxnpt,
SpiceInt * voxnpl )
AbstractReturn bookkeeping data from a DSK type 2 segment. Required_ReadingDAS DSK KeywordsDAS DSK FILES Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- handle I DSK file handle. dladsc I DLA descriptor. nv O Number of vertices in model. np O Number of plates in model. nvxtot O Number of voxels in fine grid. vtxbds O Vertex bounds. voxsiz O Fine voxel edge length. voxori O Fine voxel grid origin. vgrext O Fine voxel grid extent. cgscal O Coarse voxel grid scale. vtxnpl O Size of vertex-plate correspondence list. voxnpt O Size of voxel-plate pointer list. voxnpl O Size of voxel-plate correspondence list. Detailed_Input
handle is the handle of a DSK file containing a type 2
segment from which data are to be fetched.
dladsc is the DLA descriptor associated with the segment
from which data are to be fetched.
Detailed_Output
nv is the number of vertices in model.
np is the number of plates in model.
nvxtot is the total number of voxels in fine grid.
vtxbds are the vertex bounds. This is an array of six values giving
the minimum and maximum values of each component of
the vertex set. `vtxbds' has dimensions [3][2].
Units are km.
voxsiz is the fine grid voxel size. DSK voxels are cubes; the
edge length of each cube is given by the voxel size.
This size applies to the fine voxel grid. Units are km.
voxori is the voxel grid origin. This is the location of the
voxel grid origin in the body-fixed frame associated
with the target body. Units are km.
vgrext is the voxel grid extent. This extent is an array of
three integers indicating the number of voxels in the
X, Y, and Z directions in the fine voxel grid.
cgscal is the coarse voxel grid scale. The extent of the fine
voxel grid is related to the extent of the coarse voxel
grid by this scale factor.
vtxnpl is the vertex-plate correspondence list size.
voxnpt is the size of the voxel-to-plate pointer list.
voxnpl is the voxel-plate correspondence list size.
Parameters
See the header file
SpiceDLA.h
for declarations of DLA descriptor sizes and documentation of the
contents of DLA descriptors.
See the header file
SpiceDSK.h
for declarations of DSK descriptor sizes and documentation of the
contents of DSK descriptors.
See the header file
SpiceDSK.h
for declarations of DSK data type 2 (plate model) parameters.
Exceptions
1) If the input handle is invalid, an error is signaled by a
routine in the call tree of this routine.
2) If a file read error occurs, the error is signaled by a
routine in the call tree of this routine.
3) If the input DLA descriptor is invalid, the effect of this
routine is undefined. The error *may* be diagnosed by
routines in the call tree of this routine, but there are no
guarantees.
FilesSee input argument `handle'. ParticularsThis routine supports computations involving bookkeeping information stored in DSK type 2 segments. User applications typically will not need to call this routine. 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. 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) Dump several parameters from the first DLA segment of
a DSK file. The segment is assumed to be of type 2.
Example code begins here.
/.
Program dskb02_ex1
./
#include <stdio.h>
#include "SpiceUsr.h"
int main()
{
/.
Constants
./
#define FILSIZ 256
/.
Local variables
./
SpiceBoolean found;
SpiceChar dsk [ FILSIZ ];
SpiceDLADescr dladsc;
SpiceDouble voxori [3];
SpiceDouble voxsiz;
SpiceDouble vtxbds [3][2];
SpiceInt cgscal;
SpiceInt handle;
SpiceInt np;
SpiceInt nv;
SpiceInt nvxtot;
SpiceInt vgrext [3];
SpiceInt voxnpl;
SpiceInt voxnpt;
SpiceInt vtxnpl;
/.
Prompt for the name of DSK to read.
./
prompt_c ( "Enter DSK name > ", FILSIZ, dsk );
/.
Open the DSK file for read access. We use the
DAS-level interface for this function.
./
dasopr_c ( dsk, &handle );
/.
Begin a forward search through the kernel. In
this example, it's a very short search.
./
dlabfs_c ( handle, &dladsc, &found );
if ( !found )
{
setmsg_c ( "No segment found in file #." );
errch_c ( "#", dsk );
sigerr_c ( "SPICE(NOSEGMENT)" );
}
/.
If we made it this far, DLADSC is the
DLA descriptor of the first segment.
Read and display type 2 bookkeeping data.
./
dskb02_c ( handle, &dladsc, &nv, &np, &nvxtot,
vtxbds, &voxsiz, voxori, vgrext, &cgscal,
&vtxnpl, &voxnpt, &voxnpl );
printf ( "\n"
"Number of vertices: %d\n"
"Number of plates: %d\n"
"Number of voxels: %d\n",
(int)nv,
(int)np,
(int)nvxtot );
printf ( "Vertex bounds in X direction (km): %f : %f\n"
"Vertex bounds in Y direction (km): %f : %f\n"
"Vertex bounds in Z direction (km): %f : %f\n",
vtxbds[0][0], vtxbds[0][1],
vtxbds[1][0], vtxbds[1][1],
vtxbds[2][0], vtxbds[2][1] );
printf ( "Voxel edge length (km): %f\n"
"Voxel grid origin (km): ( %f %f %f )\n"
"Voxel grid extents: %d %d %d\n"
"Coarse voxel grid scale: %d\n"
"Size of vertex-plate list: %d\n"
"Size of voxel-plate pointer array: %d\n"
"Size of voxel-plate list: %d\n",
voxsiz,
voxori[0], voxori[1], voxori[2],
(int)vgrext[0], (int)vgrext[1], (int)vgrext[2],
(int)cgscal,
(int)vtxnpl,
(int)voxnpt,
(int)voxnpl );
/.
Close the kernel. This isn't necessary in a stand-
alone program, but it's good practice in subroutines
because it frees program and system resources.
./
dascls_c ( handle );
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, using the DSK file named phobos512.bds,
the output was:
Enter DSK name > phobos512.bds
Number of vertices: 1579014
Number of plates: 3145728
Number of voxels: 11914500
Vertex bounds in X direction (km): -13.440030 : 12.762800
Vertex bounds in Y direction (km): -11.520650 : 12.061140
Vertex bounds in Z direction (km): -9.570780 : 10.055000
Voxel edge length (km): 0.104248
Voxel grid origin (km): ( -14.073520 -11.988554 -9.903588 )
Voxel grid extents: 260 235 195
Coarse voxel grid scale: 5
Size of vertex-plate list: 11010050
Size of voxel-plate pointer array: 1151500
Size of voxel-plate list: 6419540
Restrictions
1) The caller must verify that the segment associated with
the input DLA descriptor is a DSK type 2 segment.
Literature_ReferencesNone. Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) Version
-CSPICE Version 2.1.1, 08-FEB-2021 (JDR)
Edited the header to comply with NAIF standard. Removed unnecessary
include statements from example code.
Updated example code to split printf statement in three in order to
comply with ANSI-C maximum string literal of length.
-CSPICE Version 2.1.0, 11-JUL-2016 (NJB)
Edit to example program to use "%d" with explicit casts
to int for printing SpiceInts with printf.
Removed unnecessary include statements. Updated
header.
Based on:
DSKLIB_C Version 2.0.1, 11-JUL-2014 (NJB)
Added example program to header.
DSKLIB_C Version 2.0.0, 13-MAY-2010 (NJB)
Updated for compatibility with new DSK type 2 design.
Name has been changed from dskp02_c to dskb02_c.
DSKLIB_C Version 1.0.0, 11-FEB-2010 (NJB)
Index_Entriesfetch parameters from a type 2 DSK segment |
Fri Dec 31 18:41:04 2021