isisdiff Documentation

isisdiff - Compute difference statistics between two cubes.

The "isisdiff" program checks for differences between two input cubes.
The cubes are expected to be very similar, such as the output from
processing runs on different ISIS platforms or from coding revisions.
The two cubes are required to have the same core pixel types and
dimensions.

The program computes the average difference and standard deviation
in an absolute value sense (value1 - value2) and the mean relative
difference and the relative standard deviation (value1 / value2 -1).

After processing the cubes, the program prints out statistics on
the cubes.  The number of total pixels, valid pixels, and special
pixels are shown.  The number of pixels which change their value
as well as the percentage which change are shown.  The first change
percentage is with respect to the total number of valid pixels, the
number in parenthesis is with respect to all pixels.  Similar results
are shown for special pixels.

The next printout area shows the absolute change statistics.  The
minimum and maximum absolute change are presented.  Then the
mean change is shown for those pixels whose values change (and
for the whole cube in parenthesis).  Then the mean magnitude of
changes (i.e. the mean of | value1 - value2 | ) is presented,
followed by the change standard deviation.

Next, the same statistics are shown for relative pixel changes.
Note that the relative differences are actually calculated as
(value1 / value2) - 1.0 so that displayed values of the minimum,
maximum, mean change, and mean change magnitude will be exactly
zero for no change.  Thus, negative values indicate that the
second cube is larger, while positive values indicate that the
first cube has larger pixel values.

PROGRAMMER: James M Anderson, U.S.G.S., Flagstaff, AZ

Input cube 1 file name
  (default extension is .cub)

NONE

Input subcube specifier

--

Input cube 2 file name
  (default extension is .cub)

NONE

Input subcube specifier

--

Flag to write output cubes

"NO"

Output absolute difference cube
  (default extension is .cub)

--

Output relative difference cube
  (default extension is .cub)

--

Flag to apply core scaling

"NO"

Flag to examine header lines

"NO"

ADDITIONAL NOTES:

Parm	Description
FROM1	Input cube 1 file name. If the file extension is omitted, then ".cub" will be assumed.
FROM2	Input cube 2 file name. If the file extension is omitted, then ".cub" will be assumed.
SFROM1	SFROM specifies the subcube using a single string for all three dimensions of the cube. The order of the three dimensions is always "samples:lines:bands". If a dimension is left blank, all the data for that dimension is selected. The default value of NULL for SFROM selects the entire cube. Any application below can be used for any dimension. To select specific data from any dimension: "10-100(3):11,12,15-20:1-10(2)" = This example will select every third sample starting with sample 10 thru 100. It selects lines 11 and 12, and 15-20. It selects every other band, starting with band 1 thru 10. There are special characters that can be used for selecting a subcube efficiently, such as "*","#", and "~". For examples type "help sfrom" in TAE. **NOTE** For more examples and explanation of the many features of the SFROM parameter, tutor the sfrom.pdf or refer to Introduction To ISIS, Section 6, of the ISIS User's Manual **
SFROM2	See SFROM1
DATA_OUT	Flag to write output cubes. If this variable is set to YES, two output cubes are created for the absolute and relative differences between the two input cubes.
TO_ABS	Output cube name for absolute differences. Required only if DATA_OUT==YES If the file extension is omitted, then ".cub" will be assumed.
TO_REL	Output cube name for relative differences. Required only if DATA_OUT==YES If the file extension is omitted, then ".cub" will be assumed.
APPLY_SC	If this is set to YES, the program will apply the CORE_BASE and CORE_MULTIPLIER values to the data before checking the difference statistics. Otherwise, the raw core values will be used.
HEADER	If this value is set to YES, the program will check the header of the two input cubes for differences. Each line of the headers will be compared for differences, with line differences recorded. Note that if the lines between the two input cubes get out of sync, there will be many line differences.