| dskgd_c |
|
Table of contents
Procedure
dskgd_c ( DSK, return DSK segment descriptor )
void dskgd_c ( SpiceInt handle,
ConstSpiceDLADescr * dladsc,
SpiceDSKDescr * dskdsc )
AbstractReturn the DSK descriptor from a DSK segment identified by a DAS handle and DLA descriptor. Required_ReadingDAS DSK NAIF_IDS KeywordsDAS DSK FILES TOPOGRAPHY Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- handle I Handle of a DSK file. dladsc I DLA segment descriptor. dskdsc O DSK segment descriptor. Detailed_Input
handle is the handle of a DSK file that is open for
read access.
dladsc is the DLA segment descriptor corresponding to
a DSK segment.
Detailed_Output
dskdsc is the DSK segment descriptor of the segment
designated by the input handle and DLA descriptor.
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.
Exceptions
1) If the size of the double precision component of the segment
is smaller than that of a DSK descriptor, the error
SPICE(INVALIDFORMAT) is signaled by a routine in the call tree
of this routine.
2) If the input handle is invalid, an 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.
4) If any DAS read error is detected, the error is signaled by a
routine in the call tree of this routine.
FilesSee input argument `handle'. ParticularsThis is a convenience routine intended for use by low-level routines that read DSK segments. This routine may also be called by user applications that must access DSK files at the segment level. Examples
The numerical results shown for these examples 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 the DSK descriptors of a DSK file.
Example code begins here.
/.
Program dskgd_ex1
./
#include <stdio.h>
#include "SpiceUsr.h"
int main()
{
/.
Local constants
./
#define FILSIZ 256
/.
Local variables
./
SpiceChar dsk [FILSIZ];
SpiceBoolean found;
SpiceDLADescr dladsc;
SpiceDLADescr nxtdsc;
SpiceDSKDescr dskdsc;
SpiceInt handle;
SpiceInt i;
/.
Prompt for the name of a DSK file; open the file.
./
prompt_c ( "Enter DSK name > ", FILSIZ, dsk );
dasopr_c ( dsk, &handle );
/.
Search for the first segment in the file; obtain
the segment's DLA descriptor.
./
dlabfs_c ( handle, &nxtdsc, &found );
while ( found )
{
dladsc = nxtdsc;
dskgd_c ( handle, &dladsc, &dskdsc );
printf ( "\nDSK descriptor contents:\n" );
printf ( " %15d\n", (int) dskdsc.surfce );
printf ( " %15d\n", (int) dskdsc.center );
printf ( " %15d\n", (int) dskdsc.dclass );
printf ( " %15d\n", (int) dskdsc.dtype );
printf ( " %15d\n", (int) dskdsc.frmcde );
printf ( " %15d\n", (int) dskdsc.corsys );
for ( i = 0; i < SPICE_DSK_NSYPAR; i++ )
{
printf ( " %15.6f\n", dskdsc.corpar[i] );
}
printf ( " %15.6f\n", dskdsc.co1min );
printf ( " %15.6f\n", dskdsc.co1max );
printf ( " %15.6f\n", dskdsc.co2min );
printf ( " %15.6f\n", dskdsc.co2max );
printf ( " %15.6f\n", dskdsc.co3min );
printf ( " %15.6f\n", dskdsc.co3max );
printf ( "% 15.6f\n", dskdsc.start );
printf ( "% 15.6f\n", dskdsc.stop );
/.
Fetch next DLA descriptor.
./
dlafns_c ( handle, &dladsc, &nxtdsc, &found );
}
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
DSK descriptor contents:
401
401
1
2
10021
1
0.000000
0.000000
0.000000
0.000000
0.000000
0.000000
0.000000
0.000000
0.000000
0.000000
-3.141593
3.141593
-1.570796
1.570796
8.049632
13.940940
-1577879958.816059
1577880066.183913
2) Again, dump the DSK descriptors of a DSK file, this time
interpreting the descriptor information and displaying
it in a user-friendly form. This display is a simplified
version of that created by the utility DSKBRIEF.
This program requests the name of an optional meta-kernel.
The meta-kernel can be used to define surface name-ID
associations. If no meta-kernel is needed, the user can
enter a carriage return at the prompt for this file.
Example code begins here.
/.
Program dskgd_ex2
./
#include <stdio.h>
#include "SpiceUsr.h"
int main()
{
/.
Local constants
./
#define BDNMLN 37
#define FILSIZ 256
#define FRNMLN 33
#define TIMLEN 41
#define NSYS 4
#define NAMLEN 21
#define NCLASS 2
#define SFNMLN SPICE_SRF_SFNMLN
/.
Local variables
./
SpiceBoolean found;
SpiceBoolean isname;
SpiceChar bodnam [ SFNMLN ];
SpiceChar btime [ TIMLEN ];
SpiceChar * clsnms [2] =
{ "Single-valued surface",
"General surface" };
SpiceChar dsk [ FILSIZ ];
SpiceChar etime [ TIMLEN ];
SpiceChar frame [ FRNMLN ];
SpiceChar meta [ FILSIZ ];
SpiceChar srfnam [ SFNMLN ];
SpiceChar * sysnam;
SpiceChar * sysnms [ NSYS ] =
{ "Latitudinal", "Cylindrical",
"Rectangular", "Planetodetic" };
SpiceDLADescr dladsc;
SpiceDLADescr nxtdsc;
SpiceDouble f;
SpiceDouble re;
SpiceDouble rp;
SpiceDSKDescr dskdsc;
SpiceInt bodyid;
SpiceInt corsys;
SpiceInt dclass;
SpiceInt dtype;
SpiceInt framid;
SpiceInt handle;
SpiceInt segno;
SpiceInt surfid;
prompt_c ( "Enter DSK name > ", FILSIZ, dsk );
prompt_c ( "Enter meta-kernel name > ", FILSIZ, meta );
if ( ( !eqstr_c( meta, " ") )
&& ( !eqstr_c( meta, "" ) ) )
{
furnsh_c ( meta );
}
/.
Open the DLA file and begin a forward search
for segments.
./
dasopr_c ( dsk, &handle );
segno = 0;
dlabfs_c ( handle, &nxtdsc, &found );
while ( found )
{
++segno;
/.
Make the DLA descriptor we just fetched
the current one.
./
dladsc = nxtdsc;
dskgd_c ( handle, &dladsc, &dskdsc );
bodyid = dskdsc.center;
surfid = dskdsc.surfce;
framid = dskdsc.frmcde;
dtype = dskdsc.dtype;
dclass = dskdsc.dclass;
bodc2s_c ( bodyid, BDNMLN, bodnam );
srfc2s_c ( surfid, bodyid, SFNMLN, srfnam, &isname );
frmnam_c ( framid, FRNMLN, frame );
if ( eqstr_c( frame, " " ) )
{
sprintf ( frame, "%d", (int)framid );
}
etcal_c ( dskdsc.start, TIMLEN, btime );
etcal_c ( dskdsc.stop, TIMLEN, etime );
corsys = dskdsc.corsys;
sysnam = sysnms[corsys-1];
printf ( "%s\n"
" DSK descriptor for segment %d\n"
" Body: %s\n"
" Surface: %s\n"
" Frame: %s\n"
" Start time (TDB): %s\n"
" Stop time (TDB): %s\n"
" Data type: %d\n"
" Data class: %s\n"
" Coordinate System: %s\n",
"====================================",
(int) segno,
bodnam,
srfnam,
frame,
btime,
etime,
(int) dtype,
clsnms[ dclass-1 ],
sysnam );
if ( corsys == SPICE_DSK_PDTSYS )
{
re = dskdsc.corpar[0];
f = dskdsc.corpar[1];
rp = re * (1.0 - f);
printf ( " Equatorial radius (km): %21.14f\n"
" Polar radius (km): %21.14f\n",
re, rp );
}
printf ( " Segment boundaries:\n" );
if ( corsys == SPICE_DSK_LATSYS )
{
printf ( " Longitude (deg): %21.14f %21.14f\n"
" Latitude (deg): %21.14f %21.14f\n"
" Radius (km): %21.14f %21.14f\n",
dskdsc.co1min * dpr_c(),
dskdsc.co1max * dpr_c(),
dskdsc.co2min * dpr_c(),
dskdsc.co2max * dpr_c(),
dskdsc.co3min,
dskdsc.co3max );
}
else if ( corsys == SPICE_DSK_CYLSYS )
{
setmsg_c ( "Coordinate system was Cylindrical." );
sigerr_c ( "SPICE(NOTSUPPORTED)" );
}
else if ( corsys == SPICE_DSK_RECSYS )
{
printf ( " X-coordinate (km): %21.14f %21.14f\n"
" Y-coordinate (km): %21.14f %21.14f\n"
" Z-coordinate (km): %21.14f %21.14f\n",
dskdsc.co1min,
dskdsc.co1max,
dskdsc.co2min,
dskdsc.co2max,
dskdsc.co3min,
dskdsc.co3max );
}
else if ( corsys == SPICE_DSK_PDTSYS )
{
printf ( " Longitude (deg): %21.14f %21.14f\n"
" Latitude (deg): %21.14f %21.14f\n"
" Altitude (km): %21.14f %21.14f\n",
dskdsc.co1min * dpr_c(),
dskdsc.co1max * dpr_c(),
dskdsc.co2min * dpr_c(),
dskdsc.co2max * dpr_c(),
dskdsc.co3min,
dskdsc.co3max );
}
/.
Find the next segment, if it exists.
./
dlafns_c ( handle, &dladsc, &nxtdsc, &found );
}
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, using the DSK file named phobos512.bds and an empty
string instead of the meta-kernel name, the output was:
Enter DSK name > phobos512.bds
Enter meta-kernel name >
====================================
DSK descriptor for segment 1
Body: PHOBOS
Surface: 401
Frame: IAU_PHOBOS
Start time (TDB): 1950 JAN 01 00:00:41.183
Stop time (TDB): 2050 JAN 01 00:01:06.183
Data type: 2
Data class: Single-valued surface
Coordinate System: Latitudinal
Segment boundaries:
Longitude (deg): -180.00000000000000 180.00000000000000
Latitude (deg): -90.00000000000000 90.00000000000000
Radius (km): 8.04963224872155 13.94093983212395
3) Again, dump the DSK descriptors of a DSK file, using the
program from example 2, but this time reading the DSK file
phobos_3_3_3seg.bds
which can be created by running an example program from
dskw02_c. Use the meta-kernel shown below to demonstrate surface
name-ID mapping.
KPL/MK
File: dskgd_ex3.tm
This meta-kernel is intended to support operation of SPICE
example programs. The file contents shown here should not be
assumed to contain adequate or correct versions of data
required by SPICE-based user applications.
\begindata
NAIF_SURFACE_NAME += ( 'Phobos example surface 1',
'Phobos example surface 2',
'Phobos example surface 3' )
NAIF_SURFACE_CODE += ( 1, 2, 3 )
NAIF_SURFACE_BODY += ( 401, 401, 401 )
\begintext
End of meta-kernel
When Example #2 was executed on a Mac/Intel/cc/64-bit
platform, using the DSK file named phobos_3_3_3seg.bds and the
meta-kernel dskgd_ex3.tm, the output was:
Enter DSK name > phobos_3_3_3seg.bds
Enter meta-kernel name > dskgd_ex3.tm
====================================
DSK descriptor for segment 1
Body: PHOBOS
Surface: Phobos example surface 1
Frame: IAU_PHOBOS
Start time (TDB): 1950 JAN 01 00:00:00.000
Stop time (TDB): 2050 JAN 01 00:00:00.000
Data type: 2
Data class: General surface
Coordinate System: Latitudinal
Segment boundaries:
Longitude (deg): -180.00000000000000 180.00000000000000
Latitude (deg): -90.00000000000000 90.00000000000000
Radius (km): 8.22529807597397 14.01176814562576
====================================
DSK descriptor for segment 2
Body: PHOBOS
Surface: Phobos example surface 2
Frame: IAU_PHOBOS
Start time (TDB): 1950 JAN 01 00:00:00.000
Stop time (TDB): 2050 JAN 01 00:00:00.000
Data type: 2
Data class: General surface
Coordinate System: Rectangular
Segment boundaries:
X-coordinate (km): -1.30000000000000 1.31000000000000
Y-coordinate (km): -1.21000000000000 1.20000000000000
Z-coordinate (km): -9.45293235778800 9.63817977905300
====================================
DSK descriptor for segment 3
Body: PHOBOS
Surface: Phobos example surface 3
Frame: IAU_PHOBOS
Start time (TDB): 1950 JAN 01 00:00:00.000
Stop time (TDB): 2050 JAN 01 00:00:00.000
Data type: 2
Data class: General surface
Coordinate System: Planetodetic
Equatorial radius (km): 13.00000000000000
Polar radius (km): 9.10000000000000
Segment boundaries:
Longitude (deg): -180.00000000000000 180.00000000000000
Latitude (deg): -90.00000000000000 90.00000000000000
Altitude (km): -3.72866868360370 1.37201579108146
Restrictions1) See Exception #3. Literature_ReferencesNone. Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) Version
-CSPICE Version 1.1.1, 10-AUG-2021 (JDR)
Edited the header to comply with NAIF standard. Extended the
-Exceptions section. Fixed bug in example #2.
-CSPICE Version 1.1.0, 05-APR-2017 (NJB)
Corrected a header comment typo.
22-JAN-2016 (NJB)
CSPICE header file references were updated.
Example program 1 was re-written;
example program 2 was added.
-CSPICE Version 1.0.0, 13-NOV-2012 (NJB)
Index_Entriesreturn DSK segment_descriptor |
Fri Dec 31 18:41:04 2021