AIPS HELP file for BOXFILE in 31DEC09
As of Sun Nov 22 0:15:45 2009
HELP SECTION
BOXFILE
Type: Adverb (String*48)
Use: To specify the name of a disk text file outside the usual AIPS
catalog system to be used to specify field parameters and Cleaning
areas. Up to 4096 fields may be specified and BOXFILE must be
used for fields numbered > 64 to specify RASHIFT, DECSHIFT,
FLDSIZE, or BCOMP. To specify Clean boxes for fields numbered >
1, the BOXFILE option is required. IMAGR also allows the
weights for the various spectral channels to be set using the
BOXFILE. A BOXFILE may be written or rewritten with verb
FILEBOX and by IMAGR as OBOXFILE giving the results of
interactive setting of the boxes.
Each line of text is read from the file and leading and trailing
blanks are discarded. "Column 1" as used below actually means
the first non-blank column on the card.
The field parameters are specified by giving the letter F or f in
column one, followed by the field number, the X and Y FLDSIZE, the
RASHIFT and the DECSHIFT. Values given in BOXFILE override those
given by the corresponding adverbs (including 0s).
Alternatively, the field parameters may be specified by giving the
letter C or c in column one, followed by the field number, the X
and Y FLDSIZE, and the field center right ascension (HH MM SS.S)
and declination (signDD MM SS.S) separated by blanks.
The boxes are specified by giving the field number left justified
in column one followed by, for rectangular fields, the bottom left
corner x and y and top right corner x and y pixel numbers of the
field or, for circular fields, a -1 to signify circular, the
radius in pixels, and the center x and y in pixel number for the
field. The number of Clean boxes per field is limited to
min [ 4096, (64*4096)/(NFIELD*NGAUSS) ]
To specify that a field has no Clean boxes, specify the BLC and
TRC as four zeros.
The number of components to use at the restart of an IMAGR
(BCOMP) may be given by putting the letter B or b in column one
followed by the field number and the value of BCOMP to be used.
When combining more than one spectral channel or IF, you may
wish to alter their relative weights in a temporary fashion.
The BOXFILE option allows this with W cards. Put W or w in
column 1, then a weight, then a channel number (0 -> all), and
last an optional IF number (absent -> 0, 0 -> all).
Lines in the file whose first non-blank character is anything
besides F, f, C, c, B, b, W, w, or a number 0-9 are treated as
comments. The characters # $ percent & * ; will never be used for
data and hence are the safest comment-indicating characters.
Format: The name is usually given by specifying a logical name,
followed by a colon, followed by the actual file name. In
Unix, logicals are environment variables. The logical name
must be set up before entering the AIPS program and is usually
in upper case. Thus, for example:
percent setenv MYAREA ~joeuser
for the C shell, or
$ myarea=$HOME; export MYAREA
for bourne, korn, and bash shells. Then in AIPS,
BOXFILE = 'MYAREA:CASA.BOXES'
Note that the Unix-standard $ ahead of the logical is omitted.
Other forms are now acceptable as well:
BOXFILE = 'FITS.DAT
will find the file in the directory local when you started AIPS.
A full path name may also be given
INFILE = '/home/primate2/egreisen/AIPS/Text.prt
if it fits in 48 characters. Note that the trailing quote mark
is left off and this is the last command on the input line so
that the case is preserved.
Null value: ' '
Taken to mean no subsidiary file. This is an error to FILEBOX and
means no boxes files for IMAGR and WFCLN.
Verbs:
FILEBOX......Modifies or creates a BOXFILE using the TV
Tasks:
BOXES........Adds Clean boxes to BOXFILE around sources from a list
CCEDT........Select CC components in BOXes and above mininum flux.
CHKFC........Makes images of Clean boxes from Boxfile
IMAGR........Fourier transforms and Cleans uv data with wide-field,
interactive TV, and data weighting options.
SCIMG........Full-featured imaging plus self-calibration loop
SETFC........Makes a BOXFILE for input to IMAGR
WFCLN........Fourier transforms and Cleans uv data with wide-field
options.
Examples:
To specify a field's parameters:
F 2 450 450 -25.5 6.7
specifies that field 2 is to have a FLDSIZE of 450x450 with an RASHIFT
of -25.6 and a DECSHIFT of 6.7 arcsec. If this is the only F card in
the file, then fields 1, and 3 through NFIELD are set by the adverb
values. Alternatively,
C 2 450 450 11 34 45.67 -00 14 23.1
specifies that field 2 is to have a FLDSIZE of 450x450 with a center
RA of 173.6902917 degrees and a center Declination of -0.23975
degrees. All 9 numbers must be given; the sign is optional for
positive declinations and is given only on the degrees term.
To set Clean boxes, specify one box per line, as field
field blc-x blc-y trc-x trc-y (5 integers) e.g.
1 200 205 220 222
1 230 232 240 241
2 100 100 130 121
...
or circular "boxes" as
field -1 radius center-x center-y (5 ints) e.g.
001 -1 10 210 214
001 -1 5 235 237
3 -1 15 255 513
....
Specifies 4 boxes for field 1 and one each for fields 2 and 3.
See also IMAGR and FILEBOX.
To set weights, for example:
W 0.1 1
W 0.5 2
W 0.8 2 3
W 0.1 63
assigns weight 1 to all channels 3-62, weight 0.1 to all channels 1
and 63, weight 0.5 to channel 2 except for 0.8 in channel 2, IF 3.
These "weights" multiply the weights already assigned to the data.
BCOMP values are also set. For example, to include no components
from field 98 and some from 99 include the lines:
B 98 0
B 99 243
Fields 1 through NFIELD*(Number of scales) may be specified.
EXPLAIN SECTION