| dskopn_c |
|
Table of contents
Procedure
dskopn_c ( DSK, open new file )
void dskopn_c ( ConstSpiceChar * fname,
ConstSpiceChar * ifname,
SpiceInt ncomch,
SpiceInt * handle )
AbstractOpen a new DSK file for subsequent write operations. Required_ReadingDAS DSK KeywordsDAS DSK FILES Brief_I/OVARIABLE 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.
ParametersNone. 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.
FilesSee 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.
RestrictionsNone. Literature_ReferencesNone. Author_and_InstitutionN.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_Entriesopen a new DSK file open a new DSK file with write access |
Fri Dec 31 18:41:05 2021