Help for GLLPHOT

PURPOSE

GLLPHOT is a Galileo program which reports the photometric angles: Phase,
Incidence and Emission.  The program works in 2 modes.  The program will 
either report the photometric information at any given location in an image 
(point reporting mode) or the program will output 3 files which will contain 
the photometric information for all points in the image (file output mode).
EXECUTION STATEMENT:
 
   GLLPHOT INP=PIC COORDIN=(LINE,SAMP) spice-user-parameters
or
   GLLPHOT INP=PIC COORDIN=(LAT,LON) 'LATLON spice-user-parameters
or
   GLLPHOT INP=PIC OUT=(PHA,INC,EMI) spice-user-parameters...

where
   PIC is an input image
   PHA,INC,EMI are output files which will contain the phase, incidence and
      emission values at each pixel.
   LINE,SAMP are coordinates at which the photometric values are to be reported.
   LAT,LON are coordinates at which the photometric values are to be reported.

OPERATION

GLLPHOT is a Galileo program which reports the photometric angles: Phase,
Incidence and Emission.  The program works in 2 modes.  The program will 
either report the photometric information at any given location in an image 
(point reporting mode) or the program will output 3 files which will contain 
the photometric information for all points in the image (file output mode).

Point reporting mode requires the user to provide either an image space line, 
sample pair or a latitude, longitude pair with the COORDIN parameter.  The 
COORDINTYPE parameter will then be required to indicate which type of values 
are being specified.  The keyword LINESAMP indicates the pair is a line, sample 
pair and LATLON indicates the pair is a latitude, longitude pair of values.  
The default is a LINESAMP pair.  The parameter OUT should not be used in 
conjunction with the COORDIN and COORDINTYPE parameters.  The point reporting 
mode is cancelled by the OUT parameter.

File output mode will store the 3 photometric angles: Phase, Incidence and 
Emission into three image files.  The output image files will be the same size as 
the input and of floating-point format.  The parameter OUT must specify 3 files.
The first image contains Phase angle, the second Incidence angle, and the 
third Emission angle.

The target parameter, TARGET,  can be used to override the TARGET specified in 
the VICAR label.

The point reporting mode information is formatted as such:

-------------------------------------------------------------------------------
| Spacecraft=Galileo Orbiter                                                  |
| SCET=(1996,247,17,14,29,830)                           TARGET=JUPITER       |
|                  ---------- Range from Spacecraft ----------                |
| To Central Body=2996346.63                                                  |
| To Target  Body=2996346.63             (Lat,Lon)=(-3.7329,64.3419)          |
| To Sun         =775010875.21           (Lat,Lon)=(-1.5307,344.6580)         |
|-----------------------------------------------------------------------------|
|  Line    Samp     Latitude   West Longitude                                 |
| ------   ------   --------   --------------                                 |
| 740.38   799.28   -2.0740    20.8134                                        |
|                                                                             |
|       Phase      Incidence   Emission   Hor. Scale (m)   Ver Scale (m)      |
|       --------   ---------   --------   --------------   --------------     |
|       80.5685    36.1463     44.4413    21602.4626       32108.6485         |
-------------------------------------------------------------------------------

The program is designed for Galileo's camera and similar types which has 
insignificant distortions between object space and image space.  (Voyager 
project, for example, will not run correctly here given image space COORDIN 
parameter).


NOTE: All longtitudes reported are in degrees West and all longitude inputs must
      be in degrees West.  All angles are in J2000 System.  All line, sample input
      pairs are assumed to be image space locations.

OPTIONAL USER SPICE-RELATED PARAMETERS: 

The following parameters are optional, and if defaulted (or if no data is found
in the requested version), the program will attempt to locate the "best" data
available for the given image.  

SPICEMODE specifies whether SPICE data is retrieved from LOCAL kernels or
or via the REMOTE SPICE server.  If defaulted, SPICEMODE is set to the value
of the environmental variable DEFAULTSPICE.
 
CKNAME and CKID are alternative ways to specify the C kernel to be used.  For
example, CKNAME=FARE or CKID=M904 specifies that MIPS_FARENC.CK is to be used.
When specified, the CKID parameter overrides the CKNAME parameter.  If the
camera pointing data is not found in the requested C kernel, the other C kern
are searched. CKNAME replaces the parameter formerly called SEDRSRC.

OPTIONAL USER SPICE-RELATED PARAMETERS (continued): 
 
Within a given C kernel, there may be a number of different versions of camera
pointing for a given image.  The segment identifier for each version contains
provenance information identifying the creator of the pointing data.  One or
more of the following parameters may be used to retrieve a specific instance 
camera pointing based upon this provenance information:
			
  CDATE 		Date and time the camera pointing was created.
  REQNUM 		Request number associated with the camera pointing. 
  PURPOSE 		Purpose for creating the camera pointing.
  PROGRAM 		Program which created the camera pointing.
  SPKID 		SP-kernel used to create the camera pointing.
  USERID 		User who created the camera pointing.
  GROUPID 		Group which created the camera pointing.
  INSTITUTE 		Facility which created the camera pointing.

EXAMPLES

1) gllphot s0359509200.7 coordin=(400,400)

This example will execute in point reporting mode displaying the photometric
information for the given line, sample pair.

2) gllphot s0359509200.7 coordin=(-2,20) 'LATLON

This example will execute in point reporting mode displaying the photometric
information for the given latituede, longitude pair.

3) gllphot s0359509200.7 (phase.out,incidence.out,emission.out)

This example will execute in file output mode storing the photometric
information into the 3 specified files.

PROGRAM HISTORY

Written by:            Shu-Min Chang, 14 April 1997
Cognizant Programmer:  Lucas Kamp

REVISIONS:
When       Who What
---------- --- ---------------------------------------------------------------
04/14/1997 SMC Initial Release
11/24/1998 LWK Added option for output images
11/30/1998 HBM Updated help and test pdf.

PARAMETERS: