Level 2 Help for MULTOVLY

INP specifies the input image files.  Up to ten files are allowed.

NCOL is the number of columns to be created in the output file.
Extra columns, which will be zeros, may be created.

DATACOL is a list of numbers specifying the output file columns which
receive the DN-values from the files overlayed.  DATACOL = (1,2), for
example, will list the DN-values from image file 1 in column 1, and
the values from image file 2 in column 2.  
The default is DATACOL=(1,2,3, etc).

AREACOL specifies the column in the IBIS-interaface format output file which
gets the DN-combination totals.  The default column is the n+1'th column
if there are n input images.

SUMCOL specifies the column in the IBIS-interface format output file which
gets the sum totals in TALLY mode.  The default column is the n'th column
if there are n input images.

BYTES is a list of integers, each of which is 1, 2, or 4, depending on 
whether the data in the corresponding file is in a byte, halfword, or
fullword format.  The default is to determine image format from the labels.

ZEROES is a list of input file numbers specifying those files
which, if containing a zero-valued sample, will cause the program
to include the sample and the resulting DN combination.  ZEROES = (2),for
example, will have the program include combinations where the second image
contains a zero-valued sample and the other images contain non-zero pixels.
The default is ZEROES = () which ignores zeroes in all images;  use 
ZEROES = (1,2,3,4,5,6,7,8,9,10) to include zero-valued samples for all 
image files.

TALLY is a keyword that specifies tally mode.  In tally mode the last input
image is the sum image (i.e. for each unique pixel combination in the other
images a sum over the pixels for this image will be made).  The sum results
go into the SUMCOL and the number of pixels (as usual) go into the AREACOL.