level2 Documentation

level2 - Trim and project image to sinusoidal-equal area projection
This procedure trims cleaned up unprojected image to discard the
noise around the edges, and projects the image to sinusoidal equal-
area projection.  The number of lines and samples trimmed is
determined by the program and is based on the mission.  The standard
line and sample values are listed below for the different missions.
These values can be modified by setting CHGTRVAL parameter to "yes"
and entering user defined values for TOP, BOTTOM, LEFT, and RIGHT.

The center latitude, center longitude, and scale must be the same
to mosaic the images together.  If the map resolution is not input,
it is calculated by the program to retain the full resolution of
the cleaned up unprojected image cube.  The resolution is picked in
increments of 2**n (1.pix/deg,2.,4.,..) so that any two cubes can
be made the same resolution by doubling or halving one cube.

Three programs are run in this procedure:

TRIM - trims the noise from the edges of the input images
  Viking - top=25 bottom=20 left=30 right=30
  Voyager - top=31 bottom=20 left=20 right=20
  Mariner - top=5 bottom=5 left=30 right=30
  All others - top=5 bottom=5 left=5 right=5
  User has the option of changing the default values by
	setting CHGTRVAL="yes" and entering the values for
	LEFT, RIGHT, BOTTOM, and TOP

PLANSINU - generates a lookup table file that is used by
  GEOM to transform the input file
  or
PLANORTH - generates a lookup table file that is used by
  GEOM to transform the input file

GEOM - this program actually transforms the input file
  to a sinusoidal projected image and corrects camera
  distortion.  There are two work files that are
  generated in GEOM, one the size of the input image
  and the other the size of the output image.

The table file and the two working files are deleted
after the job is completed.

** note **
  If you are projecting global images, set SINUTR parameter
  to "yes" to trim the sinusoidal image down to the exact
  latitude and longitude boundaries of the output file.

See specific programs for more help.

PROGRAMMER: Ella Mae Lee  U.S.G.S., Flagstaff, AZ

Input cube file name
  (Default extension is .cub)

NONE

Output cube file name
  (Default extension is .cub)

NONE

Transformation file
(no default extension)

tfile.dat

Image resolution (km/pix)
      or

--

Image resolution (pix/deg)

--

Center longitude of
sinusoidal image or
orthographic image
(default is center of cube)

--

Center latitude of
orthographic image
(default is center of cube)
not used for sinusoidal

--

Latitude range
(default=cube range)

--

Longitude range
(default=cube range)

--

Trim down to exact longitude
range of sinusoidal projected
image  (yes,no)

no

Input directory path
for working files
(Default = current directory)

--

Change default values to trim
edges of input cube (yes,no)

no

Number of lines to NULL at
the top of the image

5

Number of lines to NULL at
the bottom of the image

5

Number of samples to NULL
on the left side of the image

5

Number of samples to NULL on
the right side of the image

5

final output projection
TRAN - using SINU for level2
POLA - using ORTH for level2

TRAN

ADDITIONAL NOTES:

Parm	Description
FROM	Name of the unprojected cleaned up image. (Default extension is .cub)
TO	Name of the output sinusoidal image cube. (Default extension is .cub)
TFILE	Name given to a data file needed by GEOM.
KM	Specifies the map resolution in kilometers/pixel. The default will find the map resolution that will retain the full resolution of the input cube.
DEG	Specifies the map resolution in pixels/degree. The default will find the map resolution that will retain the full resolution of the input cube.
CLON	The center longitude defines the center of the projection, not necessarily the center of your input or output image. It is a parameter defined by the user of the final product. If working with images which will be computer mosaicked, then the center longitude for all those images should be the same. If the default value is used, the center longitude of the image will be used for the center longitude of the projection. The valid range is from -360 degrees to 360 degrees.
CLAT	The center latitude is used for the orthographic projection, only (in preparation for the final Polar projection output), and should be 90.0 or -90.0.
LAT	The default procedure is to automatically find the latitude and longitude range of the cube. If you want to enter your own latitude range, the longitude range must be entered also, because if this option is used, the ranges are not determined automatically. WARNING: This option is not very reliable for any cube that includes a limb.
LON	See LAT.
SINUTR	If SINUTR="yes", the program will create a TFILE that will cause GEOM to project only the area within the longitude boundaries given by the user or determined by the program. If SINUTR="no", no trimming will be done.
WORK	GEOM needs work space for two files to transform the image, one file is approximately the size of the input image and the other is aproximately the size of the output image. This option allows the work files to be sent to a different work disk.
CHGTRVAL	Change default values to trim noise along sides of input image (yes,no). If "yes", set values for TOP, BOTTOM, LEFT, and RIGHT.
TOP	Number of lines to NULL at the top of the image.
BOTTOM	Number of lines to NULL at the bottom of the image.
LEFT	Number of samples to NULL on the left side of the image.
RIGHT	Number of samples to NULL on the right side of the image.
PROJFLAG	Output projection for the mosaic and mosaic cut. Defaults to Transverse Mercator (TRAN). A Polar projection (POLA) should only be used if processing images in the Polar re- gion. For level2, the projection needed to output a Trans- verse Mercator is sinusoidal, so that is what level2 will produce when PROJFLAG is allowed to default. To output a Polar projection, set PROJFLAG to 'POLA', and level2 will produce an Orthographic projection.