AIPS HELP file for NANS in 31DEC22
As of Tue Jun 6 4:40:10 2023
NANS: Looks for NaNs in an image or a uv data set
INNAME Input file name (name)
INCLASS Input file name (class)
INSEQ 0.0 9999.0 Input file name (seq. #)
INDISK 0.0 9.0 Input file disk unit #
BCOUNT 0.0 Start vis number for search
NCOUNT 0.0 Maximum number lines printed
BLC Bottom left corner of image
TRC Top right corner of image
Task: This task will look through an image or a UV data set for
illegal numbers (NaNs). It prints their locations in the
For UV data, it counts the number of NaNs in a vis record (1
baseline, 1 time, all polarizations, spectral channels, and
IFs). It counts real and imaginary part separately and so is
likely to count 2 for every complex vis that has gone bad. It
also reports accidental cases of a binary value exactly
matching the value used as a "magic blank".
For images, it can examine a subimage if desired. It will
print detailed info about the location of NaNs for a while,
then less detailed info, and finally only a summary by plane.
Magic blanks are ignored in images (if the header says they
are there) as they are normal and handled properly.
INNAME.....Input UV or MA file name (name). Standard defaults.
INCLASS....Input UV or MA file name (class). Standard defaults.
INSEQ......Input UV or MA file name (seq. #). 0 => highest.
INDISK.....Disk drive # of input UV or MA file. 0 => any.
BCOUNT.....Start visibility number for search. 0 -> 1.
NCOUNT.....Stop printing after NCOUNT lines - 0 -> 1000.
For images, it will print detailed information about NaNs
until NCOUNT lines have been printed. It will then print
summaries, one row at a time, until another NCOUNT lines
have been printed. At that point it reverts to listing
the number of NaNs in each 2-D plane.
BLC........The bottom left-hand pixel of the sub-image to be
examined. 0's -> 1.
TRC........The top right-hand pixel of the sub-image tobe examined.
0's -> maximum on corresponding axis.