| dskd02 |
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Table of contents
Procedure
DSKD02 ( DSK, fetch d.p. type 2 data )
SUBROUTINE DSKD02 ( HANDLE, DLADSC, ITEM, START, ROOM, N, VALUES )
Abstract
Fetch double precision data from a type 2 DSK segment.
Required_Reading
DAS
DSK
Keywords
DAS
DSK
FILES
Declarations
IMPLICIT NONE
INCLUDE 'dla.inc'
INCLUDE 'dskdsc.inc'
INCLUDE 'dsk02.inc'
INTEGER HANDLE
INTEGER DLADSC ( * )
INTEGER ITEM
INTEGER START
INTEGER ROOM
INTEGER N
DOUBLE PRECISION VALUES ( * )
Brief_I/O
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
HANDLE I DSK file handle.
DLADSC I DLA descriptor.
ITEM I Keyword identifying item to fetch.
START I Start index.
ROOM I Amount of room in output array.
N O Number of values returned.
VALUES O Array containing requested item.
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.
ITEM is an integer "keyword" parameter designating the
item to fetch. In the descriptions below, note
that "model" refers to the model represented by
the designated segment. This model may be a
subset of a larger model.
Names and meanings of parameters supported by this
routine are:
KWDSC DSK descriptor of segment. See the
INCLUDE file dskdsc.inc for a
discussion of the contents of DSK
descriptors. Note that DSK
descriptors are not to be confused
with DLA descriptors, which contain
segment component base address and
size information.
KWVTBD Vertex bounds. This is an array of
six values giving the minimum and
maximum values of each component of
the vertex set.
KWVXOR Voxel grid origin. This is the
location of the voxel grid origin in
the body-fixed frame associated with
the target body.
KWVXSZ 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.
START is the start index within specified data item from
which data are to be fetched. The index of the
first element of each data item is 1.
ROOM is the amount of room in the output array. It
is permissible to provide an output array
that has too little room to fetch an item in
one call.
Detailed_Output
N is the number of elements fetched to the output
array VALUES. N is normally in the range
1:ROOM; if an error occurs on the call, N is
undefined.
VALUES is a contiguous set of elements of the item
designated by ITEM. The correspondence of
VALUES with the elements of the data item is:
VALUES(1) ITEM(START)
... ...
VALUES(N) ITEM(START+N-1)
If an error occurs on the call, VALUES is
undefined.
Parameters
See the include file
dla.inc
for declarations of DLA descriptor sizes and documentation of the
contents of DLA descriptors.
See the include file
dskdsc.inc
for declarations of DSK descriptor sizes and documentation of the
contents of DSK descriptors.
See the include file
dsk02.inc
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.
4) If ROOM is non-positive, the error SPICE(VALUEOUTOFRANGE)
is signaled.
5) If the coarse voxel scale read from the designated segment
is less than 1, the error SPICE(VALUEOUTOFRANGE) is signaled.
6) If the input keyword parameter is not recognized, the error
SPICE(NOTSUPPORTED) is signaled.
7) If START is less than 1 or greater than the size of the
item to be fetched, the error SPICE(INDEXOUTOFRANGE) is
signaled.
Files
See input argument HANDLE.
Particulars
Most SPICE applications will not need to call this routine. The
routines DSKV02, DSKP02, and DSKZ02 provide a higher-level
interface for fetching DSK type 2 vertex and plate data.
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.
Note that the DSK descriptor for the segment is not needed by
this routine; the DLA descriptor contains the base address and
size information for the integer, double precision, and character
components of the segment, and these suffice for the purpose of
fetching data.
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) Look up all the vertices associated with each plate
of the model contained in a specified type 2 segment.
For this example, we'll show the context of this look-up:
opening the DSK file for read access, traversing a trivial,
one-segment list to obtain the segment of interest.
Example code begins here.
PROGRAM DSKD02_EX1
IMPLICIT NONE
INCLUDE 'dla.inc'
INCLUDE 'dskdsc.inc'
INCLUDE 'dsk02.inc'
C
C Local parameters
C
CHARACTER*(*) FMT
PARAMETER ( FMT = '(1X,A,3(1XE15.8))' )
INTEGER FILSIZ
PARAMETER ( FILSIZ = 255 )
C
C Local variables
C
CHARACTER*(FILSIZ) DSK
DOUBLE PRECISION VRTCES ( 3, 3 )
INTEGER DLADSC ( DLADSZ )
INTEGER HANDLE
INTEGER I
INTEGER J
INTEGER K
INTEGER N
INTEGER NP
INTEGER START
INTEGER VRTIDS ( 3 )
LOGICAL FOUND
C
C Prompt for the name of the DSK to read.
C
CALL PROMPT ( 'Enter DSK name > ', DSK )
C
C Open the DSK file for read access.
C We use the DAS-level interface for
C this function.
C
CALL DASOPR ( DSK, HANDLE )
C
C Begin a forward search through the
C kernel, treating the file as a DLA.
C In this example, it's a very short
C search.
C
CALL DLABFS ( HANDLE, DLADSC, FOUND )
IF ( .NOT. FOUND ) THEN
C
C We arrive here only if the kernel
C contains no segments. This is
C unexpected, but we're prepared for it.
C
CALL SETMSG ( 'No segments found '
. // 'in DSK file #.' )
CALL ERRCH ( '#', DSK )
CALL SIGERR ( 'SPICE(NODATA)' )
END IF
C
C If we made it this far, DLADSC is the
C DLA descriptor of the first segment.
C
C Find the number of plates in the model.
C
CALL DSKI02 ( HANDLE, DLADSC, KWNP, 1, 1, N, NP )
WRITE (*,*) 'Number of plates: ', NP
C
C For the first 5 plates, look up the desired data.
C
K = MIN(5, NP)
DO I = 1, K
C
C For the Ith plate, find the associated
C vertex IDs. We must take into account
C the fact that each plate has three
C vertices when we compute the start
C index.
C
START = 3*(I-1)+1
CALL DSKI02 ( HANDLE, DLADSC, KWPLAT, START,
. 3, N, VRTIDS )
DO J = 1, 3
C
C Fetch the vertex associated with
C the Jth vertex ID. Again, each
C vertex is a 3-vector. Note that
C the vertices are double-precision
C data, so we fetch them using
C DSKD02.
C
START = 3*( VRTIDS(J) - 1 ) + 1
CALL DSKD02 ( HANDLE, DLADSC, KWVERT, START,
. 3, N, VRTCES(1,J) )
END DO
C
C Display the vertices of the Ith plate:
C
WRITE (*,*) ' '
WRITE (*,*) 'Plate number: ', I
WRITE (*,FMT) ' Vertex 1: ', (VRTCES(J,1), J=1,3)
WRITE (*,FMT) ' Vertex 2: ', (VRTCES(J,2), J=1,3)
WRITE (*,FMT) ' Vertex 3: ', (VRTCES(J,3), J=1,3)
END DO
C
C Close the kernel. This isn't necessary in a stand-
C alone program, but it's good practice in subroutines
C because it frees program and system resources.
C
CALL DASCLS ( HANDLE )
END
When this program was executed on a Mac/Intel/gfortran/64-bit
platform, using the DSK file named phobos512.bds, the output
was:
Enter DSK name > phobos512.bds
Number of plates: 3145728
Plate number: 1
Vertex 1: -0.67744400E+01 0.62681500E+01 0.60114900E+01
Vertex 2: -0.67623800E+01 0.62572800E+01 0.60255600E+01
Vertex 3: -0.67571000E+01 0.62775400E+01 0.60209600E+01
Plate number: 2
Vertex 1: -0.67744400E+01 0.62681500E+01 0.60114900E+01
Vertex 2: -0.67797300E+01 0.62479000E+01 0.60161000E+01
Vertex 3: -0.67623800E+01 0.62572800E+01 0.60255600E+01
Plate number: 3
Vertex 1: -0.67797300E+01 0.62479000E+01 0.60161000E+01
Vertex 2: -0.67676800E+01 0.62370100E+01 0.60301900E+01
Vertex 3: -0.67623800E+01 0.62572800E+01 0.60255600E+01
Plate number: 4
Vertex 1: -0.67797300E+01 0.62479000E+01 0.60161000E+01
Vertex 2: -0.67849900E+01 0.62276200E+01 0.60207000E+01
Vertex 3: -0.67676800E+01 0.62370100E+01 0.60301900E+01
Plate number: 5
Vertex 1: -0.67849900E+01 0.62276200E+01 0.60207000E+01
Vertex 2: -0.67729900E+01 0.62167400E+01 0.60348200E+01
Vertex 3: -0.67676800E+01 0.62370100E+01 0.60301900E+01
Note that only the vertex information for first 5 plates is
provided.
Restrictions
1) This routine uses discovery check-in to boost
execution speed. However, this routine is in
violation of NAIF standards for use of discovery
check-in: routines called from this routine may
signal errors. If errors are signaled in called
routines, this routine's name will be missing
from the traceback message.
Literature_References
None.
Author_and_Institution
N.J. Bachman (JPL)
J. Diaz del Rio (ODC Space)
B.V. Semenov (JPL)
Version
SPICELIB Version 1.0.1, 13-AUG-2021 (JDR) (BVS)
Edited the header to comply with NAIF standard. Modified code
example to reduce the output.
SPICELIB Version 1.0.0, 04-FEB-2017 (NJB)
Fixed typo in version description.
23-AUG-2016
Now saves NV and updates it only when the current
segment changes.
15-JAN-2016 (NJB)
Removed code involving parameter NP.
Updated header $Examples section.
DSKLIB Version 3.0.0, 13-MAY-2010 (NJB)
Updated for compatibility with new DSK type 2
segment design.
DSKLIB Version 2.1.0, 20-APR-2010 (NJB)
Bug fix: changed declaration of output argument
VALUES to double precision.
DSKLIB Version 2.0.0, 27-DEC-2006 (NJB)
Updated to remove support for min, max radius
lookup. These values are now stored in DSK
descriptors.
DSKLIB Version 1.0.0, 27-OCT-2006 (NJB)
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Fri Dec 31 18:36:15 2021