levinit Documentation

levinit - Initialize the processing information on the labels
This program initializes the geometric processing information for
a cube or table file.  This program supports a variety of space-
craft instruments.  You may attempt to run this program on any
cube or table file and it will indicate if the instrument is not
supported.

The program updates the following in the labels:

     1. ISIS_TARGET group
     2. ISIS_GEOMETRY group
     3. ISIS_INSTRUMENT group

It starts by obtaining the TARGET_NAME from the ISIS_TARGET group.
It uses the value to locate the newest "definition" file for the
target.  For example, if the TARGET_NAME is mars, this program
will find the file $ISISDATA/targets/mars.def.2 and records it on
the labels.  This "def" file contains various target
characteristics (e.g., radii, positive longitude direction, etc).
Any geometric processing programs such as "lev1stats",
"lev1tolev2", etc will use this information in their calculations.
The default target definition file can be overridden by the user
assigning the TARGDEF parameter to the desired file (include path).
Documentation is included in the def files and it is recommended that
the user update the documentation when modifying the def file.

Next the program determines which NAIF Spice kernels are required
for geometric processing of the data.  It does this by examining
a time stamp contained in the labels and then automatically
searches for a file containing a list of kernels.  For example,
the MGS/MOC instrument searches for the file
$ISISMGSDATA/moc_kernels.def.1 and records it on the labels.
Then the program determines the minimum set of kernels required
to geometrically process the data and writes those to the labels
under the ISIS_GEOMETRY group.  Again, any geometric processing
programs such as "lev1stats", etc will use these kernels in
their calculations.  The default kernel list can be overridden
by the user using the KERNLST parameter.  For instruments using
reseaux, the program will write the nominal reseaux locations to
the ISIS_GEOMETRY group also.

Finally, the program searches for a file containing instrument
parameters such as focal length, boresight, etc.  For example,
MGS/MOC searches for the file $ISISMGSDATA/moc_parameters.def.1
and records it on the labels.  Again, any geometric processing
programs will use the parameters in the "def" file in their
calculations.  The default parameter list can be overridden
using the INSTPARS parameter.


PROGRAMMER:  Debbie A. Cook, USGS, Flagstaff, AZ

Input "level 0" or "level 1"
cube name or table file

NONE

Target definition filename

--

Kernel list filename

--

Instrument parameters filename

--

Longitude system
(default 0 to 360)

360

Latitude system
(default OGRAPHIC)

"OGRAPHIC"

Update kernels only in geometry
group (default NO)

"NO"

ADDITIONAL NOTES:

Parm	Description
FROM	Input file name of either a "level 0" or "level 1" cube or a "level 0" table file (e.g., mola profile). If the file extension is omitted, then ".cub" or ".tbl" will be assumed.
TARGDEF	This parameter is used to specify different target parameters (radius, omega 0, etc). The default is to read the target from the cube labels and construct a filename of the form "target.def.version". For example, if Mars is the target in the labels then the default value will be "$ISISDATA/targets/mars.def.1". Actually, the version will be the highest version number found under the $ISISDATA directory. If the user needs to define their own target parameters simply copy a file from $ISISDATA/targets and modify as needed.
KERNLST	This parameter is used to specify a file containing a list of SPICE kernels. The program will select a sub-set of these kernels which covers the time-range for the input cube. The names of the selected kernels will be written to the labels of the cube.
INSTPARS	This parameter is used to specify a file containing instrument parameters (boresight, focal length, etc). The default is instrument specific. For example, MGS/MOC may attempt to open "$ISISMGSDATA/moc.def.1". This file is versioned identically to the method defined under TARGDEF. If the user needs to define their own instrument parameters simply copy the appropriate instrument file from the mission data area (e.g., $ISISCLEMDATA) and modify as needed.
LONSYS	This parameter is used to define the longitude system computed by "lev1" programs. Valid values are either 180 or 360. The default is 360 which implies longitudes will be output in the range of 0 to 360. The value 180 implies longitudes will be output in the range of -180 to 180. Your selection is written to the labels of the cube or table file. This effects programs which output or use the latitude, for example, "qview", "lev1stats", "lev1tolev2".
LATSYS	This parameter is used to define the latitude system computed by "lev1" programs. Valid values are either OGRAPHIC or OCENTRIC. The default is OGRAPHIC. Your selection is written to the labels of the cube or table file. This effects programs which output or use the latitude, for example, "qview", "lev1stats", "lev1tolev2".
KERNONLY	This parameter can be used to preserve the reseaux locations in the ISIS_GEOMETRY group. In the default case, the entire group is deleted and rewritten by the program. If KERNONLY=YES, then the reseau positions on the labels before the program is run will be saved. Instruments without reseaux can ignore this parameter, because the program will run the same whether the parameter is set to YES or NO. This parameter should be used whenever the reseaux have already been removed and the user desires to update kernel files, the target file, or the instrument file without losing the computed reseau locations.