Level 2 Help for PTP

INP

STRING - Input image.
INP must be in byte or halfword format.

If INP is from Voyager or any earlier mission it must be a geometrically
corrected image.

If INP is from Galileo or any later mission, it must be a raw (uncorrected)
image.


OUT

STRING - Output image
The output image format will be in the same data format as the input image
(byte or halfword).


REF

STRING - Reference image
The input image (INP) is projected to the same perspective as the reference
image. 

PTP extracts SCET, camera serial number, and target-id from the VICAR label
and used these data to retrieve the navigation data from the SPICE server.

If the reference image is not available, it may be replaced by specifying the
RSCET, RCAM, and TARGET parameters.


RSCET

6 integers
(SCETYear, SCETDay, SCETHour, SCETMin, SCETSec, SCETMSec)
SpaceCraft Event Time of reference frame.


RCAM

OPTIONAL INTEGER
Camera serial number for reference image.  If defaulted, the camera ID is
obtained from the VICAR label of the reference image.

The camera serial number is used to retrieve the focal length, line and sample
of the optical-axis intercept point, and the picture scale from built-in
tables.  The current values in these tables are:

		      CAMERA	 FOCAL	  LAXIS  SAXIS  PSCALE (pixels/mm)
        CASSI NAC       1       2000.00    512    512   83.333333
	CASSI WAC       2        200.736    "      "      "
        CASSI NAC 2x2  21       2000.00    256    256   41.666665
	CASSI WAC 2x2  22        200.736    "      "      "
        CASSI NAC 4x4  41       2000.00    128    128   20.833333
	CASSI WAC 4x4  42        200.736    "      "      "

        GLL             1       1501.039   400    400   65.6167979 
        GLL 2x2 sum     2	1501.039   200    200   32.8083990

	VGR-2 WA        4	 200.770   500    500   84.821428
	VGR-2 NA        5	1503.49     "      "      "
	VGR-1 WA        6	 200.465    "      "      "
	VGR-1 NA        7	1500.19     "      "      "

        VIKOR 1A        7	474.610    575    625   85.0
        VIKOR 1B        4	474.398     "      "      "
        VIKOR 2A        8	474.101     "      "      "
        VIKOR 2B        6	474.448     "      "      "

        MAR10 A         1      1495.66     400    475   74.78
        MAR10 B         1      1503.69     400    475   74.78

        MAR-9           1	 52.267    400    475   75.0     
        MAR-9		2	500.636     "      "      "

Note: These tables are obtained via a call to VICAR subroutine GETCAMCON.  For
active missions, these values may be updated as they are more accurately
determined.


RMISSION

OPTIONAL KEYWORD
Spacecraft ID of reference image
     e.g.  RMISSION=CASSI
VALID=(VGR-1,VGR-2,GLL,CASSI,VIKOR)
If defaulted, RMISSION is assumed to be the same as the input image.


RADII

OPTIONAL REAL

PTP uses a triaxial ellipsoid model of the planet, defined by three radii
(equatorial long axis, equatorial short axis, and polar) in km:

    EX:  RADII=(1811.3, 1805.2, 1793.1)

If defaulted, the values are obtained via a call to subroutine PBDATA.


RP

OPTIONAL REAL
polar radius of oblate spheroid target body (km)


RE

OPTIONAL REAL
equatorial radius of oblate spheroid target body (km)


ROT

OPTIONAL REAL
Target body rotation rate (deg/day)
E.g: ROT=870.536


PC

OPTIONAL REAL
Planet center of input image specified as (line,sample).
 Example: PC=(123.23,432.34)


RPC

OPTIONAL REAL
Planet center of reference image specified as (line,sample).
 Example: PC=(123.23,432.34)


SPICEMODE

SPICEMODE=LOCAL specifies that SPICE data is to be retrieved from local
SPICE kernels.  SPICEMODE=REMOTE specifies that SPICE data is to be retrieved
via the SPICE server.  If SPICEMODE is defaulted, the logical name (or
environmental variable) DEFAULTSPICE is used to determine whether LOCAL or
REMOTE is used.  Note that if SPICE data is not found in LOCAL or REMOTE mode,
the other mode is attempted.

The processing method is fixed by GETSPICE2 to REMOTE for VGR data as of
6/12/96.  This is only a temporary.


INCLUDE

If the 'INCLUDE keyword is specified, all output pixels not on the planet are
generated by offsetting the sky background of the input image by a constant
(the difference between the planet centers).  No perspective geometry is used,
and the planet ring system is treated as though no rotation has occured.
Also, there will be areas of the planet visible from the perspective of the
output image but not visible in the input image (e.g. the area may have rotated
behind the planet).  These areas are generated by using the corresponding
points in front of the planet.  Note that this is a "cludgy" solution.
Beware of odd side effects if the rotation is large.

If INCLUDE is not specified, the sky background is deleted (output
as 0 dn's).  This is the default.


EXACT

By default, the projection is calculated for a grid of tiepoints (the grid 
spacing is 32 x 32 pixels).  All output pixels within the square area 
defined by any four neighboring grid points are projected via interpolation.
In areas of the image where this interpolation generates errors larger than 
1/2 pixel (e.g. the limb), the grid spacing is reduced in successive steps 
(16x16, 8x8, 4x4) until a 1/2 pixel accuracy is achieved.

If the keyword 'EXACT is specified, the projection is computed using the exact
equations at each pixel (rather than via interpolation).


TARGET

Ex: TARGET=GANYMEDE specifies that GANYMEDE is the target in the input image.

The TARGET may be a planet, satellite, or asteroid.  If defaulted, the target
name is extracted from the VICAR label or determined by other TBD means.

A complete list of valid target names is located in the ASCII file assigned
the logical name (or environmental variable) BODY_IDS.


CKNAME

CKNAME is a four character string specifying the C-kernel to be used:

  CKNAME	C KERNEL
  --------      -------------
  DAVI		MIPS_DAVI.CK
  NAV		MIPS_NAV.CK
  FARE		MIPS_FARENC.CK
  NAV2		MIPS_NAV2.CK
  NEAR		MIPS_NEAR.CK
  AMOS		MIPS_AMOS.CK
  NAIF		the best NAIF kernel is used

If defaulted, the kernels are searched in the above order.


CKID

CKID is an alternative way to specify the prefered C-kernel (see CKNAME
parameter):

  CKID	  CKNAME	C KERNEL
  ----	  --------      -------------
  M906	  DAVI		MIPS_DAVI.CK
  M905	  NAV		MIPS_NAV.CK
  M904	  FARE		MIPS_FARENC.CK
  M903	  NAV2		MIPS_NAV2.CK
  M902	  NEAR		MIPS_NEAR.CK
  M901	  AMOS		MIPS_AMOS.CK
  varies  NAIF		there are a large number of these files

Ex:  CKID=M901 specifies the four character ID which uniquely identifies the
     C-kernel MIPS_AMOS.CK.

A complete list of the C-kernel IDs is located in the ASCII file assigned the
logical name (or environmental variable) KERNELDB.

If specified, CKID overrides the CKNAME parameter.


USERID

USERID is a three character string which identifies the user who created the
camera pointing.

Ex:  USERID=HBM identifies Helen Mortensen as the creator of the camera
     pointing.


GROUPID

GROUPID is a three character string which identifies the group which created the
camera pointing.

Ex:  GROUPID=040 identifies group 040 as the creator of the camera pointing.


INSTITUTE

INSTITUTE is a four character string identifying the facility which created
the camera pointing.

Ex:  INSTITUTE=MIPS specifies that MIPS created the camera pointing.


PURPOSE

PURPOSE is a four character string identifying the purpose of the observation
or the purpose of processing.  For example,
  PURPOSE=MOSA identifies the image as part of a mosaic sequence
  PURPOSE=COLO identifies the image as part of a color sequence


PROGRAM

PROGRAM is the first six characters of the program creating the camera pointing.

Ex:  PROGRAM=FARENC specifies that FARENC created the camera pointing.


SPKID

SPKID specifies the four character ID which uniquely identifies the
SP kernel used to create the camera pointing.  The SP-kernel IDs are located
in the ASCII file assigned the logical name (or environmental variable)
KERNELDB.

Ex:  SPKID=N015 specifies the SP kernel GLL_LONG_2.BSP


REQNUM

REQUNUM is a four character string identifying the IPL request number for
which the camera pointing was created.

Ex:  REQNUM=3456 identifies (somewhat) request number R123456


CDATE

Date and time the camera pointing was created in the form 'YEARMMDDHHMM'.

Ex:  CDATE=199602291200 specifies that the pointing was created at noon
     on February 29, 1996.