1. Obtain the program by anonymous ftp from ceps.nasm.edu (192.138.170.27).
The material is in /pub/venus. The ftp directory contains the
source code, mgn_data.f, along with a compiled version made using
the static options to allow the code to run on machines that do
not have Fortran installed. This program was set up on a Sun Sparc
workstation but should be VAX-compatible with some adjustments
to the read statements that access the CD-ROM.
2. Compile the program on your machine using [f77 -e -o mgn_data
mgn_data.f], or just use the already compiled version if your
machine will accept it.
3. Mount a CD-ROM with the desired image product.
5. Using whatever display program you choose, set up one of the
framelets such that you can read the (x,y) pixel locations of
points within the image.
6. From the CD-ROM directory of the chosen MIDR, run the compiled
program in a separate window.
7. The program will ask for (a) a destination file path and name
for the output log file, (b) what type of incidence angle profile
this image used, (c) whether this is a C-MIDR or F-MIDR, and (d)
the name of the framelet label file you want to work with. Version
2 of this program now permits all four DLAP modes to be selected
(left, right, stereo, Maxwell).
8. Once it gets the mapping information from the image header,
the program allows you to select corner points of boxes within
the framelet. It will then report the (latitude, longitude) boundaries
of the box, the range of incidence angles, and the mean and standard
deviation of all non-zero pixels. The output average echo is in
backscatter cross section per unit area (backscatter coefficient)
and has had the Muhleman correction taken out. The values in parentheses
following the mean echo, in decibels, are the coefficients at
plus and minus one standard deviation, also in decibels.
For each box you may also add a one-line annotation to indicate
the terrain type on the log file.
A sample run of the program and its output follows.
/cdrom/c130n045: 3>mgn_data
Name of the data log file (in single quotes)?
'/home/campbell/guide/logfile'
Input label file from a Magellan CD-ROM?
c1f28.lbl
Specify DLAP for this image:
Left-looking: l
Right-looking: r
Cycle 3 Maxwell: m
Stereo: s
l
Is this an F-MIDR or a C-MIDR (c or f)?
c
Upper left (x,y) and lower right (x,y) of box?
248,18,313,82
Description of site for log file (s. quotes)?
'Plains Unit 1'
Box coordinates:
Upper left lat, lon: 30.99926 43.50247
Upper right lat, lon: 30.99926 43.66403
Lower left lat, lon: 30.86304 43.50522
Lower right lat, lon: 30.86304 43.66654
Range of angle across the box: 41.71 41.76
Number of non-zero points in box: 4290
Mean and standard deviation of SAR: 0.0153 0.0039
Mean SAR echo in decibels: -18.140 (-19.397, -17.166)
Would you like another box?
y
Upper left (x,y) and lower right (x,y) of box? 241,269,270,291
Description of site for log file (s. quotes)?
'Bright Lava Flow'
Box coordinates:
Upper left lat, lon: 30.46505 43.49583
Upper right lat, lon: 30.46505 43.56751
Lower left lat, lon: 30.41822 43.49676
Lower right lat, lon: 30.41822 43.56841
Range of angle across the box: 41.92 41.94
Number of non-zero points in box: 690
Mean and standard deviation of SAR: 0.1660 0.0376
Mean SAR echo in decibels: -7.799 ( -8.914, -6.912)
Would you like another box?
y
Upper left (x,y) and lower right (x,y) of box? 383,137,458,188
Description of site for log file (s. quotes)?
'Moderate Lava Flow'
Box coordinates:
Upper left lat, lon: 30.74599 43.84222
Upper right lat, lon: 30.74599 44.02813
Lower left lat, lon: 30.63744 43.84400
Lower right lat, lon: 30.63744 44.02971
Range of angle across the box: 41.81 41.85
Number of non-zero points in box: 3952
Mean and standard deviation of SAR: 0.0758 0.0199
Mean SAR echo in decibels: -11.202 (-12.522, -10.191)
Would you like another box?
N
Data from Magellan Image Framelet: C1F28.IMG
Part of Magellan Image: C1-MIDR.30N045;201
Pixel scale of image (m): 225.000
Plains Unit
Box pixel boundaries (x1,y1,x2,y2): 248 18 313 82
Box coordinates:
Upper left lat, lon: 30.99926 43.50247
Upper right lat, lon: 30.99926 43.66403
Lower left lat, lon: 30.86304 43.50522
Lower right lat, lon: 30.86304 43.66654
Range of angle across the box: 41.71 41.76
Number of non-zero points in box: 4290
Mean and standard deviation of SAR: 0.0153 0.0039
Mean SAR echo in decibels: -18.140 (-19.397, -17.166)
Bright Lava Flow
Box pixel boundaries (x1,y1,x2,y2): 241 269 270 291
Box coordinates:
Upper left lat, lon: 30.46505 43.49583
Upper right lat, lon: 30.46505 43.56751
Lower left lat, lon: 30.41822 43.49676
Lower right lat, lon: 30.41822 43.56841
Range of angle across the box: 41.92 41.94
Number of non-zero points in box: 690
Mean and standard deviation of SAR: 0.1660 0.0376
Mean SAR echo in decibels: -7.799 ( -8.914, -6.912)
Moderate Lava Flow
Box pixel boundaries (x1,y1,x2,y2): 383 137 458 188
Box coordinates:
Upper left lat, lon: 30.74599 43.84222
Upper right lat, lon: 30.74599 44.02813
Lower left lat, lon: 30.63744 43.84400
Lower right lat, lon: 30.63744 44.02971
Range of angle across the box: 41.81 41.85
Number of non-zero points in box: 3952
Mean and standard deviation of SAR: 0.0758 0.0199
Mean SAR echo in decibels: -11.202 (-12.522, -10.191)