AIPS HELP file for SDIMG in 31DEC24
As of Fri Apr 26 23:02:36 2024
SDIMG: Select & grid random-position single-dish measurements
INPUTS
INNAME Input UV file name (name)
INCLASS Input UV file name (class)
INSEQ 0.0 9999.0 Input UV file name (seq. #)
INDISK 0.0 9.0 Input UV file disk unit #
Cal. info for input:
DOCALIB -1.0 2.0 If >0 calibrate data
GAINUSE CS table to apply
FLAGVER Flag table version
STOKES Stokes' parameter to image.
BIF 0.0 IF (if any) to select
BCHAN 0.0 4096.0 First spectral channel
ECHAN 0.0 4096.0 Last spectral channel
OUTNAME Output UV file name (name)
OUTCLASS Output UV file name (class)
OUTSEQ 0.0 9999.0 Output UV file name (seq. #)
OUTDISK 0.0 9.0 Output UV file disk unit #.
OPTYPE Projection code e.g. '-SIN'
APARM 1,2,3 = RA (h,m,s)
4,5,6 = Dec (d,m,s)
IMSIZE 32. 4096. Image size (X,Y) in pixels
CELLSIZE 0.000001 4096. Cell size in arc seconds
ROTATE Rotate image CCW (degrees)
SHIFT (X,Y) image shift in asec
UVWTFN UV dist. weight function
'UN' => uniform count
'WT' => uniform weights
other => natural
UVBOX 0. 128. Additional rows and columns
used in weighting. Use 0.
REWEIGHT (1) <= 0 -> interp image
= 1 -> convolved image
= 2 -> weight image
= 3 -> 1/sigma**2 image
(2) Min convolved weight
= REWEIGHT(2) *
max(convolved weight)
< 0 => use abs value
XTYPE -20. 20. Conv. function type in x
default spheroidal
New round types - SEE HELP
YTYPE -20. 20. Conv. function type in y
default spheroidal
XPARM Conv. function parms for x
YPARM Conv. function parms for y
BADDISK Disk drive #'s to avoid
HELP SECTION
SDIMG
Task: This task will select random position single dish data in AIPS uv
form in a specified field of view about a specified position and
project the coordinates onto the specified coordinate system.
Calibration and flagging may be applied during the selection
process. It will then convolve the data onto a grid. The input
data may be in any sort order - they will be sorted by SDIMG into
the order needed for gridding.
Task SDGRD is recommended for most single-dish imaging. However,
SDIMG has been made available to do images too large for SDGRD.
It does this by having one or even two scratch file copies of the
input data so that the projecting may be done ahead of a sort on
the projected coordinates. Uniform weighting is probably not
desirable in single-dish imaging, but it is available in SDIMG.
It is not offered by SDGRD.
Adverbs:
INNAME.....Input single-dish data file name (name).
INCLASS....Input single-dish data file name (class).
INSEQ......Input single-dish data file name (seq. #).
INDISK.....Disk drive # of input single-dish data file.
DOCALIB....If true (>0) then calibrate the data using information in
the specified CS table.
GAINUSE....Version number of the CS table to apply to the
data if DOCALIB=1. 0 = highest numbered.
FLAGVER....Specifies the version of the flagging table to be
applied. 0 => highest numbered table.
<0 => no flagging to be applied.
STOKES.....Stokes' type of the desired image:
'I' => I polarization,
'Q' => Q polarization,
'U' => U polarization,
'V' => V polarization,
'RR' => right circular polarization,
'LL' => left circular polarization,
'VV' => vertical linear polarization
'hh' => horizontal linear polarization
other => 'I'
BIF........IF number to grid (only one is done). 0 => 1.
BCHAN......First spectral channel to grid, 0 => 1.
ECHAN......Last spectral channel to grid; <BCHAN => max.
OUTNAME....Output file name (name). blank => INNAME
OUTCLASS...Output file name (class). blank => INCLASS
OUTSEQ.....Output file name (seq. #). 0 => lowest unique
OUTDISK....Disk drive # of output UV file. 0 => highest with
space for the file.
OPTYPE.....Projection code:
'-TAN' = tangent projection (optical),
'-SIN' = sine projection (normal interferometer),
'-ARC' = arc projection (Schmidt camera, single
dish images),
'-NCP' = North celestial pole (WSRT),
'-STG' = stereographic projection,
Those below should have latitude reference value 0.0
'-AIT' = Aitoff projection, (large field)
'-GLS' = Global sinusoidal projection (large field)
'-MER' = Mercator projection (large field)
'-CAR' = Plate Carree ("cartesian'")
'-MOL' = Molweide's (large field)
'-PAR' = Parabolic (Craster - for large field)
' ' => '-SIN'
See AIPS memo nos. 27 and 46 for more detail.
APARM......1,2,3 are the RA as (h,m,s)
4,5,6 are the Dec, as (d,m,s)
The specified position is the CENTER of the RA and DEC
range before the application of the shifts (if any).
Default: uv data header RA and DEC, or, if they are 0, uv
data header Observed RA and Dec. If the data coordinates
are relative Az-El (i.e. beam switched data), then there is
no default and 0,0 would be the normal center.
If APARM(4) is -0 then use APARM(4)=-0.1.
IMSIZE.....(X,Y) image size in pixels. Must be even and
between 32 and 4096.
CELLSIZE...(X,Y) cell size in arc seconds.
ROTATE.....Rotate image CCW by ROTATE degrees.
SHIFT......Probably wouldn't do what you expect: shifts the reference
pixel by SHIFT(1)/CELL(1), -SHIFT(2)/CELL(2). The
reference value is set by APARM (see above). For a normal
Ra-Dec image, if both SHIFTs are > 0, the center of the
image will be at a higher Ra and higher Dec than the
reference point.
UVWTFN.....Spatial weighting function for data:
'UN' => "Uniform" (spatial weights = 1/# pts in
the cell)
'WT' => "uniform weights" (spatial weights =
1 / sum of data weights in cell)
other => "Natural" (all spatial weights = 1)
UVBOX......(U,V) box size for smoothing. See HELP UVBOX.
ZEROSP.....The first value is used to set the minimum sum of
convolving function weights (times data weights
scaled down by the maximum data weight). 0 => 0.01
REWEIGHT...(1) Selects the kind of output image:
<= 0 => interpolated image (convolved image
divided by a convolved image with the
data replaced by 1.0's).
= 1 => convolved image of data.
= 2 => convolved image with data replaced by 1,
i.e an image of the data weights (sum of
input data weight * uniform weight
correction * convolving function at each
cell)
= 3 => image of K/sigma**2 for an interpolated
image assuming the input weights are
K/sigma**2 for the data samples
(2) Minimum convolved weight (image with data
replaced by 1.0's) to remain unblanked =
REWEIGHT(2) * max(convolved weight).
< 0 => use abs(convolved weight) compared to
abs(REWEIGHT(2)*max(convolved weight))
0 => -0.01. for interpolation output and no
blanking for convolution and weight
outputs
XTYPE......Convolution function type in X-direction
1=Pillbox, 2=exponential, 3=Sinc, 4=Exp*Sinc,
5=Spheroidal, 6=Exp*BESSJ1(x)/x
= 0 or > 6 (& < 11) -> 5.
11 - 16 => circular functions in radius corresponding to
1 - 6 types above; YTYPE, YPARM are ignored.
If XTYPE < 0, then abs(xtype) is used and some of the XPARM
values are assumed to be in arc seconds rather than cells.
See HELP UV1TYPE through HELP UV6TYPE for details.
YTYPE.....Convolution function type in Y-direction
XPARM.....Array containing parameters for XTYPE.
See HELP UVnTYPE when n=convolution type.
XPARM(5) is number samples of convolution function
used per image cell for circular functions - 100 is
used for X/Y separable functions (types 1-6)
YPARM.....Array containing parameters for YTYPE.
BADDISK...Disk drive #'s to avoid for scratch files
EXPLAIN SECTION