pointvu Documentation

pointvu - Project undistorted point perspective with topography
POINTVU will project spacecraft image cubes of irregular bodies such as
Phobos or Amalthea to a map projection.  One of four map projections
may be used: Sinusoidal equal-area, Equirectangular cylindrical, Simple
cylindrical (same as Equirectangular cylindrical with clat=0) or
Orthographic.  It can also be used to make new Point Perspective views
from a map base.  A topographic base of the body in the Sinusoidal,
Equirectangular cylindrical, Simple cylindrical orOrthographic
projection must exist before this program can be used.  Any Point
Perspective image cube (Viking and Voyager LEVEL1 image cubes are
in Point Perspective) input to this program must be undistorted.  To
remove camera distortions, run NOPROJ, then GEOM.

Projecting a spacecraft image cube to the map base requires two steps:
the topographic map base first must be projected to the same point
perspective view as the image cube with option TOP2IMG; then the
spacecraft image cube is projected to the map base with the option
IMG2MAP.  (The options are described below.)

Once a topographic map base and an image map base exists, new Point
Perspective image views can be created with the option MOVIE.
Topographic "movies" can also be created without an image map base
by using OPTION=TOP2IMG and entering the same parameters as for
OPTION=MOVIE.

If a topographic Point Perspective was created with this program and
then the pixel values were altered by some other program, it can be
reprojected to the map base with the option TOP2MAP.  Caution:  the
pixel values of the topography are no longer the local radii when the
topography is projected to the Point Perspective by this program.
They are now the distance from the image plane to the surface of the
planet minus a constant.  The constant is the magnitude of the
spacecraft vector minus the major equatorial radius of the planet.

NOTE: The topographic base is expected to have the vertical resolution
units in CORE_UNIT.  The valid values are: kilometers, meters, or feet.
The DATUM keyword may also exist which gives the base of the map in
kilometers.  The default is 0.0 which means that the topo values are
given from the ceter of the planet.

PROGRAMMER: Kay Edwards, USGS, Flagstaff, AZ

Input image cube name
(Default extension is .cub)
(optional)

--

Input topo cube name
(Default extension is .cub)

NONE

Input image cube to match
(Default extension is .cub)
(optional)

--

Output topo or image cube name
(Default extension is .cub)

NONE

TOP2IMG=TOPO(MAP)>TOPO(POINT)
IMG2MAP=IMAGE(POINT)>IMAGE(MAP)
MOVIE  =IMAGE(MAP)>IMAGE(POINT)
TOP2MAP=TOPO(POINT)>TOPO(MAP)

MOVIE

3X3 LPFZ filter of cube (YES,NO)

Use the following parameters
when OPTION=MOVIE or TOP2IMG
and no  reference file is input:

NO

Subspacecraft latitude (deg)

--

Subspacecraft longitude (deg)

--

Height above planet (km)

--

Focal length of camera in
pixels

--

Number of lines

--

Number of samples

Use the following parameters
when OPTION=TOP2MAP or IMG2MAP:

--

Map projection (SINU,SIMP,ORTH)

SINU

Map base resolution (km/pix)
          or

--

Map base resolution (pix/deg)

8.

Center longitude of map base

180.

Center latitude of map base

0.

Map latitude range

-90.,90.

Map longitude range

0.,360.

ADDITIONAL NOTES:

Parm	Description
FROM	Input image cube file name. If the file extension is omitted, then ".cub" will be assumed. This file is needed when OPTION=IMG2MAP or OPTION=MOVIE. When OPTION=IMG2MAP, the image cube must be in the Point Perspective. When OPTION=MOVIE, the image cube must be in the map projection.
TOPO	Input topography cube file name. If the file extension is omitted, then ".cub" will be assumed. This file is needed for all options. When OPTION=TOP2IMG or OPTION=MOVIE, the topography cube must be in a map projection (SINU, SIMP or ORTH). (The same projection as the image cube). When OPTION=IMG2MAP, the topography cube must be in the same Point Perspective as the image cube. When OPTION=TOP2MAP, the topography cube must be in a Point Perspective.
REF	Input reference image cube file name. If the file extension is omitted, then ".cub" will be assumed. This file is needed when OPTION=TOP2IMG to define the viewing geometry of the Point Perspective image cube that the topography cube needs to match. This file may also be used when OPTION= MOVIE when the viewing geometry of the "movie" is too complex to use the parameters: SLAT, SLON, HEIGHT, FL, NL and NS. If topographic "movies" are being created, this file is not needed. Use SLAT, SLON, HEIGHT, FL, NL and NS.
TO	Output cube file name. If the file extension is omitted, then ".cub" will be assumed. This file may be either an image cube or a topography cube depending on the option. (See the table in OPTION.)
OPTION	Each option requires the input files to be in different projections shown in the following table: OPTION |-----INPUT CUBES----| OUTPUT FROM TOPO REF CUBE PROJECTION ______________________________________ TOP2IMG ---- MAP POINT TOPO POINT IMG2MAP POINT POINT ---- IMAGE MAP MOVIE MAP MAP (POINT) IMAGE POINT TOP2MAP ---- POINT ---- TOPO MAP OPTION DESCRIPTION TOP2IMG Project the topography cube from a map base to the same Point Perspective as the REF image cube to be projected or a new Point Perspective by using SLAT, SLON, HEIGHT, FL, NL and NS IMG2MAP Project the image cube from Point Perspective to a map base. The topography cube must be projected to the same Point Perspective before this option is used. MOVIE Project the image cube from a map base to a new Point Perspective. TOP2MAP Project the topography cube from Point Perspective to a map base.
FILTER	A 3x3 low pass filter of non-valid data will be run on the output cube if FILTER=Y.
SLAT	The subspacecraft latitude and longitude must be entered if no REF cube is entered for OPTION=MOVIE.
SLON	See SLAT
HEIGHT	The height of the spacecraft in kilometers must be entered if no REF cube is input for OPTION=MOVIE.
FL	The focal length of the camera must be given in pixels, if no REF cube is used for OPTION=MOVIE. The following table gives the focal lengths used in ISIS: MISSION SPACECRAFT CAMERA FOCAL LENGTH (PIXELS) ------- ---------- ------ --------------------- Mariner 9 A 3907.1 Mariner 9 B 37423.5 Mariner 10 A 111804. Mariner 10 B 112472. Viking all all 40282. Voyager 1 WA 17630. Voyager 1 NA 127000. Voyager 2 WA 17639. Voyager 2 NA 128000.
NL	The number of lines and samples of the output cube must be given if REF input cube is not used. The following table gives the sizes of several UNDISTORTED mission image cubes: MISSION NL NS ------- ---- ---- Galileo 800 800 Mariner 800 950 Viking 1150 1250 Voyager 1000 1000
NS	The number of samples for the output cube. See NL for sizes of undistorted image cubes for several missions.
PROJ	Three projections are allowed, Sinusoidal equal-area, Simple cylindrical and Orthographic.
KM	The map resolution in km/pixel.
DEG	The map resolution in pixels/degree.
CLON	The center longitude of the map base. The valid range is from -360 to 360 degrees. This parameter is needed by all three projections.
CLAT	The center latitude of the map base. The valid range is from -90 to 90 degrees. This parameter is needed by the Orthographic and the Simple cylindrical projection.
LON	The longitude range of the map base. The valid range is from -360 to 360 degrees.
LAT	The latitude range of the map base. The valid range is from -90 to 90 degrees.