cspice_dskrb2

 Abstract I/O Examples Particulars Required Reading Version Index_Entries

#### Abstract

```
CSPICE_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/O

```
Given:

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 is the equatorial radius

corpar is the flattening coefficient. Let `re' and
`rp' represent, respectively, the equatorial and
polar radii of the reference ellipsoid of the
system. Then

corpar = ( re - rp ) / re
the call:

cspice_dskrb2, vrtces, plates, corsys, corpar, mncor3, mxcor3

returns:

mncor3    is a lower bound on the range of the third coordinate
of the system identified by `corsys' and `corpar', taken
over all plates.

For latitudinal and rectangular coordinates, `mncor3'
is the greatest lower bound of the third coordinate.

For planetodetic coordinates, `mncor3' is an
approximation: it is less than or equal to the greatest
lower bound.

mxcor3    is the least upper bound on the range of the third
coordinate of the system identified by `corsys' and
`corpar', taken over all plates.

```

#### Examples

```
Any 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...'

cspice_dskrb2, vrtces, plates, corsys, corpar, mncor3, mxcor3

print, 'Done.'

;;
;; Write the segment to the file.
;;
print, 'Writing segment...'

cspice_dskw02, handle, \$
center, \$
surfid, \$
dclass, \$
frame,  \$
corsys, \$
corpar, \$
mncor1, \$
mxcor1, \$
mncor2, \$
mxcor2, \$
mncor3, \$
mxcor3, \$
first,  \$
last,   \$
vrtces, \$
plates, \$
spaixd, \$
spaixi

end

;;
;; Close the input DSK.
;;
cspice_dskcls, handle, SPICETRUE
cspice_dascls, inhan

END

IDL outputs:

Reading input data...
Done.
Creating segment        1
Creating spatial index...
Done.
Computing radius bounds of plate set...
Done.
Writing segment...
Creating segment        2
Creating spatial index...
Done.
Computing Z-coordinate bounds of plate set...
Done.
Writing segment...
Creating segment        3
Creating spatial index...
Done.
Computing altitude bounds of plate set...
Done.
Writing segment...

After run completion, A DSK exists in the output directory.

```

#### Particulars

```
Users 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.

```

```
ICY.REQ
DAS.REQ
DSK.REQ

```

#### Version

```
-Icy Version 1.0.0, 14-DEC-2016, ML (JPL), EDW (JPL)

```

#### Index_Entries

```
compute range bounds for type 2 dsk segment

```
`Wed Apr  5 17:58:00 2017`