AIPS HELP file for IMLOD in 31DEC24
As of Wed May 1 19:23:26 2024
IMLOD: Task to store an image from a FITS or IBM-CV data file
INPUTS
INTAPE 0.0 9.0 Input tape drive # (0 => 1)
OUTNAME Image name (name)
OUTCLASS Image name (class)
OUTSEQ -1.0 9999.0 Image name (seq. #)
0 => highest unique number
-1 => FITS tape value
OUTDISK 0.0 9.0 Disk drive # (0 => any)
NCOUNT 0.0 999.0 Number of files to load.
DOTABLE -1.0 1.0 True (1.0) means load tables
NFILES -9999.0 9999.0 # of files to advance on tape
NMAPS 0.0 999.0 # IBM maps to advance on tape
DATAIN Disk file name (FITS only)
ERROR -1.0 3.0 >= 2 -> do not use AIPS
history in the FITS file
HELP SECTION
IMLOD
Type: Task
Use: IMLOD loads a map from tape or disk to an AIPS catalog disk. The
format may be the "IBM" map format or the FITS format. The task
converts the file map header into the standard form and stores the
header in the header file. The map array is then stored in a
separate disk file in the same catalog location. The tape is
positioned after the End-of-file mark for FITS tapes or after the
last row for IBM tapes. Thus, for the latter an EOF may be the
next record. If any TABLES data are found on a FITS tape or disk
file, they may be converted to additional extension files of the
image. This applies to Clean Components and other AIPS table
files written by FITTP or FITAB and to some general tables written
by other systems. If IMAGE extensions are present, they are
written to separate catalog entries, but all TABLES are attached
to the primary catalog entry.
IMLOD (and PRTTP, UVLOD, FITLD, TPHEAD) now understand and
interpret the standard world coordinate system keywords CDi_j
and PCi_j. They are used if possible and problems reported.
Adverbs:
INTAPE......The input tape drive #. 0 => 1.
OUTNAME.....The output image name (name). Standard behavior
with default = the original map file name (FITS),
the source name, or 'NONE'.
OUTCLASS....The output image name (class). Standard behavior
with default = the original map class (FITS) or a
class of the form 'STYP ', where S = (I, Q, U, V)
Stokes parameter of the image and TYP = (BEM, CLN,
MAP) for a beam, clean map, or anything else.
Special combination images (OPTD et al.) are also
recognized.
OUTSEQ......The output image name (seq #). 0 => Find the
lowest number which produces a unique mapname.
-1 => use the sequence number on the tape (if
any - works only on tapes written by FITTP).
OUTDISK.....The disk drive #. 0 => highest with space
NCOUNT......The number of consecutive files to load from tape.
DOTABLE.....True (1.0) means load all tables. (FITS only).
NFILES......# of files to skip on tape before reading data
1 => start of next file, -1 => start of previous
file. 0 => not tape movement before read. Use
the AIPS verb AVFILE if needed to position at the
start of the current (or other) file plus TPHEAD
to make sure you are at the right place.
NMAPS.......For IBM map format there can be more than map in a
single tape file. IMLOD first positions at the
start of the requested file (with NFILES), then
advances NMAPS into the file (for IBM format
only).
DATAIN......48-character name of the disk file from which to
read a FITS file. It must be in the form
:
or
:::
where is the remote computer name,
is the environment variable (logical
name) for the disk area in which the file named
is stored. is usually omitted
when the file is local to the current computer.
ERROR......>= 2 => do not parse AIPS history cards found in the FITS
header. Do not use this option until you have tried IMLOD
without it. If you get mysterious errors (usually error 4
which implies premature end of file), then try IMLOD with
ERROR set to 2. For a period of time, UV data sets written
out with FITAB, read back in, processed, and then written
out with FITTP could have so many AIPS history records in
their header as to cause IMLOD to read the data wrongly.
EXPLAIN SECTION
IMLOD: Task to store an image from a FITS or IBM-CV tape
Documentor: E.B.Fomalont
Related Programs: PRTTP, FITTP, AVTP, MOUNT, DISMOUNT
PURPOSE
IMLOD is the task used to read images from tape or disk to disk in
the format used by AIPS. There are two formats recognized by AIPS are
FITS format and IBM-map format. FITS format is the most general and
images can be written on tape or disk in this format from many
institutions. The IBM-map format is an old format which is compatible
with an old tape format used in Charlottesville. IMLOD is able to
distinguish between these two formats.
FITTP and FITAB are the AIPS tasks which generate a FITS tape or
file from an image on disk.
In FITS, each image is contained in a separate file. For
spectral-line work the image may consist of many planes. More than one
image can be loaded with one execution of IMLOD if they are in
consecutive files on the tape. Certain extension files may be
associated with an image. At the present time general tables files and
clean-components files written by FITTP will be read into AIPS using
IMLOD.
FITS format files can be read from a disk file on one of
the AIPS disks. This uses the adverb DATAIN.
COMMENTS
OUTNAME, OUTCLASS, OUTSEQ, OUTDISK
If OUTNAME is unspecified, the following will be taken:
Original outname used when writing image
Source name
'NONE'
If OUTCLASS is unspecified, the following will be taken:
Original outclass used when writing image
Class of form 'STYP' where S is the Stokes parameter
and TYP is the type of image
'IMAP'
If OUTSEQ = 0
Lowest available sequence number for the specified
OUTNAME and OUTCLASS and OUTDISK
If OUTSEQ = -1
Original outseq used when writing image
Lowest available sequence number for the specified
OUTNAME and OUTCLASS and OUTDISK.
NCOUNT
Number of consecutive files to load. If NCOUNT is zero then
one file will be loaded.
DOTABLES
If DOTABLES is false (-1) then table files such as CC files
will not be loaded from tape. If these files are not
needed this option can greatly increase loading time.