[daip] UVPLT EXPLAIN file & weights
Michael Rupen
mrupen at nrao.edu
Wed Jan 16 12:03:56 EST 2008
Dear DAip,
the EXPLAIN file for UVPLT says that setting BPARM(8) (the "number of
bins" parameter) negative will lead to using the data weights in the bin
averages. A quick check suggests this is not true; DOWEIGHT seems to
control whether or not the data weights are used, even for negative
BPARM(8). To me this seems like a Good Thing.
Note that this use of negative BPARM(8) is described in both the
help associated with BPARM(8), and in the COMMENTS/AVERAGING section.
I've attached a revised HELP file which I believe is correct, based on
31DEC08.
Cheers,
Michael
-------------- next part --------------
; UVPLT
;---------------------------------------------------------------
;! plots data from a UV data base
;# Task UV Plot
;-----------------------------------------------------------------------
;; Copyright (C) 1995-1998, 2000-2007
;; Associated Universities, Inc. Washington DC, USA.
;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
;; published by the Free Software Foundation; either version 2 of
;; the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public
;; License along with this program; if not, write to the Free
;; Software Foundation, Inc., 675 Massachusetts Ave, Cambridge,
;; MA 02139, USA.
;;
;; Correspondence concerning AIPS should be addressed as follows:
;; Internet email: aipsmail at nrao.edu.
;; Postal address: AIPS Project Office
;; National Radio Astronomy Observatory
;; 520 Edgemont Road
;; Charlottesville, VA 22903-2475 USA
;-----------------------------------------------------------------------
UVPLT LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
UVPLT Plots data from a u,v data base: multi-channel version
USERID -32000.0 32000.0 Data base owner number
INNAME Input UV file name (name)
INCLASS Input UV file name (class)
INSEQ 0.0 9999.0 Input UV file name (seq. #)
INDISK Input UV file disk unit #
SOURCES Sources to plot, ' '=>all.
QUAL -10.0 Qualifier -1=>all
CALCODE Calibrator code ' '=>all
STOKES Stokes type to select.
SELBAND Bandwidth to select (kHz)
SELFREQ Frequency to select (MHz)
FREQID Freq. ID to select.
TIMERANG Time range to select
ANTENNAS Antennas to plot
BASELINE Baselines with ANTENNAS
UVRANGE UV range in kilolambda.
SUBARRAY 0.0 1000.0 Subarray, 0 => all
BCHAN 0.0 4096.0 1st spectral channel #
ECHAN 0.0 4096.0 Last spectral channel #
CHINC 0.0 4096.0 Increment in channel #
BIF Low IF number to plot
EIF Highest IF number to plot
DOCALIB -1.0 101.0 > 0 calibrate data & weights
> 99 do NOT calibrate weights
GAINUSE CAL (CL or SN) table to apply
DOPOL -1.0 10.0 If >0 correct polarization.
BLVER BL table to apply.
FLAGVER Flag table version
DOBAND -1.0 10.0 If >0 apply bandpass cal.
Method used depends on value
of DOBAND (see HELP file).
BPVER Bandpass table version
SMOOTH Smoothing function. See
HELP SMOOTH for details.
XINC 0.0 9999.0 Plot every XINC'th visibility
0 => 1.
BPARM Control parameters
1 : X-axis type 0=>UV dist
2 : Y-axis type 0=>Ampl
1=> amplitude (Jy)
2=> phase (degrees)
3=> uv dist. (klambda)
4=> uv p.a. (deg N->E)
5=> time (IAT days)
6=> u (klambda)
7=> v (klambda)
8=> w (klambda)
9=> Re(Vis) (Jy)
10=> Im(Vis) (Jy)
11=> time (IAT hours)
12=> log(ampl)
13=> weight
14=> HA (hours)
15=> elevation (deg)
16=> parallactic angle
17=> uv dist. (klambda)
along p.a.
18=> azimuth (deg)
3 : > 0.0 => fixed scale
< 0.0 => fixed range
4 : Xmin (fixed scale)
5 : Xmax (fixed scale)
6 : Ymin (fixed scale)
7 : Ymax (fixed scale)
8 : Number of bins in plot.
9 : > 0 => list bin values.
10: > 0 => plot auto-corr too
BPARM=6,7,2,0 generates
square UV coverage plots
DOWEIGHT -1.0 1.0 > 0 use weights in binning
REFANT 0.0 90.0 > 0 => use REFANT for plot
types 14, 15, 16, 18
ROTATE -360.0 360.0 uv p.a. for projection
(deg N->E); type 17 only
FACTOR -1000.0 1000.0 Scale dots by FACTOR
< 0 => connect dots too
DO3COL -1.0 1.0 > 0 use 3-color to separate
channels and IFs.
LTYPE -10.0 10.0 Type of labeling: 1 border,
2 no ticks, 3 - 6 standard,
7 - 10 only tick labels
<0 -> no date/time
BADDISK Disk to avoid for scratch.
DOTV -10.0 10.0 > 0 Do plot on the TV, else
make a plot file
GRCHAN 0.0 8.0 Graphics channel 0 => 1.
----------------------------------------------------------------
UVPLT
Type: Task
Use: Plots data from a u,v data base making a plot file. Calibration
information can be applied before plotting. If calibration
information is to be applied, the data must be in TB sort order.
Adverbs:
USERID.....Input file user number. 0 => logon user,
32000 => any user.
INNAME.....Input UV file name (name) Standard defaults.
INCLASS....Input UV file name (class) Standard defaults.
INSEQ......Input UV file name (seq. #) 0 => highest.
INDISK.....Disk drive # of input UV file. 0 => any.
SOURCES....List of sources to be plotted. ' '=> all; if any starts
with a '-' then all except ANY source named.
QUAL.......Qualifier of source to be plotted. -1 => all.
CALCODE....Calibrator code of sources to plot. ' '=> all.
STOKES.....The desired Stokes type of the plotted data:
'I','Q','U','V', 'IV', 'IQU', 'IQUV'
'RR','LL', 'RL', 'LR', 'RRLL', 'RLLR', 'RLRL'
'XX','YY', 'XY', 'YX', 'XXYY', 'XYYX', 'XYXY'
'HALF', 'CROS', and 'FULL' have sensible interpretations
depending on the Stokes present in the data. The last in
each of the 3 rows above == 'FULL'.
All selected Stokes will be plotted
SELBAND....Bandwidth of data to be selected. If more than one IF is
present SELBAND is the width of the first IF required.
Units = kHz. For data which contain multiple bandwidths or
frequencies the task will insist that some form of
selection be made by frequency or bandwidth.
SELFREQ....Frequency of data to be selected. If more than one IF is
present SELFREQ is the frequency of the first IF required.
Units = MHz.
FREQID.....Frequency identifier to select (you may determine which is
applicable from the OPTYPE='SCAN' listing produced by
LISTR). If either SELBAND or SELFREQ are set, their values
overide that of FREQID. However, setting SELBAND and
SELFREQ may result in an ambiguity. In that case, the task
will request that you use FREQID. If all SELBAND, SELFREQ
and FREQID are not specified (<= 0) then the task will loop
over the frequency ID plotting all of them!
TIMERANG...Time range of the data to be plotted. In order:
Start day, hour, min. sec, end day, hour, min. sec.
Days relative to reference date.
ANTENNAS...A list of the antennas to plot. If any number is negative
then all antennas listed are NOT desired and all others
are. All 0 => list all.
BASELINE...Baselines are specified using BASELINE.
Eg. for baselines 1-6,1-8, 2-6 and 2-8
use ANTENNAS=1,2; BASELINE=6,8.
UVRANGE....Range of projected spacings to be plotted in 1000's of
wavelengths. 0 => 1, 1.E10
SUBARRAY...Subarray number to plot. 0 => all - the task will
loop over subarray number.
BCHAN......Beginning spectral line channel number. 0 => 1.
ECHAN......Ending spectral line channel number. 0 => max.
CHINC......Increment in spectral line channel number. 0 => 1.
BIF........First IF number to plot. 0 => 1
EIF........Last IF number to plot. 0 => highest
DOCALIB....If true (>0), calibrate the data using information in the
specified Cal (CL) table for multi-source or SN table for
single-source data. Also calibrate the weights unless
DOCALIB > 99 (use this for old non-physical weights).
GAINUSE....Version number of the Cal. table to apply to the data if
DOCALIB=1. Refers to a CL table for multi-source data or
an SN table for single-source. 0 => highest.
DOPOL......If > 0 then correct data for instrumental polarization as
represented in the AN table. Only one subarray may be done
at a time. This correction is only useful if PCAL has
been run or feed polarization parameters have been
otherwise obtained. See HELP DOPOL for available correction
modes.
BLVER......Version number of the baseline based calibration (BL) table
to apply. <0 => apply no BL table, 0 => highest, if any.
FLAGVER....Specifies the version of the flagging table to be applied.
0 => highest numbered table. <0 => no flagging to be
applied.
DOBAND.....(multi-source) If true (>0), then correct the data for the
shape of the antenna bandpasses using the BP table
specified by BPVER. The correction has five modes:
(a) if DOBAND=1 all entries for an antenna in the table
are averaged together before correcting the data.
(b) if DOBAND=2 the entry nearest in time (including
solution weights) is used to correct the data.
(c) if DOBAND=3 the table entries are interpolated in
time (using solution weights) and the data are then
corrected.
(d) if DOBAND=4 the entry nearest in time (ignoring
solution weights) is used to correct the data.
(e) if DOBAND=5 the table entries are interpolated in
time (ignoring solution weights) and the data are then
corrected.
BPVER......(multi-source) specifies the version of the BP table to be
applied. 0 => highest numbered table.
SMOOTH.....Specifies the type of spectral smoothing to be applied to
a uv database . The default is not to apply any smoothing.
The elements of SMOOTH are as follows:
SMOOTH(1) = type of smoothing to apply: 0 => no smoothing
To smooth before applying bandpass calibration
1 => Hanning, 2 => Gaussian, 3 => Boxcar, 4 => Sinc
To smooth after applying bandpass calibration
5 => Hanning, 6 => Gaussian, 7 => Boxcar, 8 => Sinc
SMOOTH(2) = the "diameter" of the function, i.e. width
between first nulls of Hanning triangle and sinc
function, FWHM of Gaussian, width of Boxcar. Defaults
(if < 0.1) are 4, 2, 2 and 3 channels for SMOOTH(1) =
1 - 4 and 5 - 8, resp.
SMOOTH(3) = the diameter over which the convolving
function has value - in channels. Defaults: 1,3,1,4
times SMOOTH(2) used when input SMOOTH(3) < net
SMOOTH(2).
XINC.......Plot every XINC'th visibility which might be plotted.
0 => 1.
BPARM......Control parameters:
1,2 = type of X-axis and type of Y-axis- where,
1 = amplitude (Jy), 2 = phase (degrees),
3 = u,v distance (klambda), 4 = u,v p.a.(deg, N thru E)
5 = time (IAT days), 6 = u (+max at left, bottom)
7 = v, 8 = w (all in klambda),
9 = real part (Jy) 10 = imaginary part (Jy)
11 = time (IAT hours) 12 = log (amplitude)
13 = vis weight 14 = hour angle (hours)
15 = elevation (degrees) 16 = parallactic angle (deg)
17 = uv dist. in p.a. ROTATE 18 = azimuth (deg)
**********************************************
Use -n to plot the parameter from max at left or bottom to min
at right or top rather than the usual order (opposite for u).
**********************************************
BPARM(1)=0 => 3 -- X-axis type is u,v, distance
BPARM(2)=0 => 1 -- Y-axis type is Amplitude (Jy)
For single-dish data: 1 and 9 are flux, 2 and 10 are offset, 3,
6, and 8 are longitude, 4 and 7 are latitude.
3 = if greater than zero, use BPARM(4) - BPARM(8) as the ranges of
the axes. If less than zero, use the BPARMs to limit the range
of the axes, but self-scale the axes within that range. If
0.0, fully self-scaling. Each axis treated separately.
4 = Minimum of X-axis - used if BPARM(5) > BPARM(4).
5 = Maximum of X-axis - used if BPARM(5) > BPARM(4).
6 = Minimum of Y-axis - used if BPARM(7) > BPARM(6).
7 = Maximum of Y-axis - used if BPARM(7) > BPARM(6).
8 = If = 0, plot each selected sample individually.
If > 0, plot bin averages in X of the specified quantity.
There will be BPARM(8) number of bins in the plot. For bins
with more than 2 entries the vertical height of the symbol
represents the standard deviation of the mean of the
distribution in the bin except that the minimum height
plotted = width of the + symbol. Self-scaling will be on
binned values.
If < 0, bin the data in abs(BPARM(8)) bins. Plot the
individual samples as line type 4 and the bin averages as
line type 3. The binned values include individual samples
outside the plot range (BPARM(6) - BPARM(7)) but those
samples are plotted only if they fit in the plot range.
9 = If > 0, then the values and standard deviations in each bin
will be put in the message file (prio=5). Has no effect if the
plot is not binned.
10 If > 0, then the auto-corelations, if there are any, will also
be plotted.
BPARM=6,7,2,0 will generate a UV coverage plot with identical U and
V limits.
DOWEIGHT...> 0 => use data weights in averaging the binned data
(BPARM(8) not zero).
REFANT.....Hour angle, elevation, parallactic angle, and azimuth
are actually antenna parameters not baseline parameters.
If REFANT > 0, these plot parameters will be those
evaluated at antenna REFANT.
If REFANT = 0, these parameters are
evaluated at each antenna of an antenna pair and averaged
for plotting purposes.
ROTATE.....Position angle, in degrees N thru E, for the projected uv
distance. This parameter is only used if BPARM(1)=17
or BPARM(2)=17.
FACTOR.....Multiplier to make plotted points larger or smaller.
abs (FACTOR)< 0.1 => 1. FACTOR < 0 => connect the dots
and draw the symbol.
DO3COL.....> 0 => use 3-color vectors in the plot symbols to allow
the channels and IFs to be distinguished. BIF, BCHAN is
full red, EIF,ECHAN is full blue.
LTYPE......Labelling type: 1 = border, 2 = no ticks, 3 - 10 =
standard, with 7-10 all labels other than tick numbers
and axis type are omitted. Less than 0 is the same except
that the plot file version number and create time are
omitted.
BADDISK....Disk numbers to avoid for scratch files. Scratch files may
be created by the sorting routines if calibration or
flagging is applied.
DOTV.......> 0 => plot directly on the TV device, otherwise make a
plot file for later display on one or more devices
(including the TV if desired).
GRCHAN.....Graphics channel (1 - 7) to use for line drawing. 0 => 1.
----------------------------------------------------------------
UVPLT: Plots data from a u,v data base making a plot file.
RELATED PROGRAMS: TKPL,PRTPL,TVPL
PURPOSE
UVPLT can be used to plot any pair of variables from a u,v data
base i.e. any of u, v, w, uv distance, uv position angle, visibility
amplitude, phase, real, imaginary. It is very useful as a diagnostic
tool. Some possible uses :
1. Plotting visibility amplitude or phase as a function of uv
distance to find a useful uv range for selfcalibration. Use the
averaging option.
2. Plotting visibility amplitude or phase of the residuals of a set
of clean components from a data base as a function of uv distance to
find bad points which can be clipped using task CLIP. The task UVSUB
can be used to subtract or add the visiblity corresponding to a set of
clean components. For the purpose of spotting bad visibility points it
is recommended that all clean components up to the first negative be
subtracted before running UVPLT.
3. Plotting u against v will give the uv plane coverage of the data
set.
4. Plotting visibility amplitude or phase as a function of uv
distance to guesstimate a reasonable value for the zero spacing flux to
be used in IMAGR. Values > 110-120% of the maximum correlated flux will
lead to spurious results in cleaning.
COMMENTS
BCHAN, ECHAN, BIF, EIF:
More than one frequency may be plotted from multi-channel, multi-IF
data sets. The data will be plotted at u,v,w values corrected to the
frequency of the individual channel and IF. This is useful in seeing
the effect of bandwidth synthesis.
UVRANGE :
Allows selection of points to be plotted on the basis of distance
from the centre of the uv plane.
AVERAGING :
A very nice option allows the averaging of the data into bins. The
average and rms in a bin is plotted in place of the individual values.
This is mainly useful for seeing the overall shape of the visibility
curve. Default scaling is by the extrema of the axes. BPARM(8)
switches on the averaging and sets the number of bins. The sign of
BPARM(8) controls whether (<0) or not (>0) the individual samples
are also plotted.
SCALING :
The default scaling is from the maximum to the minimum of an axis.
The entire data base must be read to determine the scaling so you can
halve the execution time of UVPLT by specifying the maximum and minimum
values. If BPARM(3) > 0.0, then BPARM(4) - BPARM(7) control the scaling
of the 2 axes. If, however, any of the BPARM4) - BPARM(7) is zero, then
that parameter will be self-scaled. If you actually want 0.0 for a
limit, set some small negative (for lower limits) or positive (for upper
limits) amount..
The option of setting BPARM(3) < 0.0 is useful to restrict the data
to some range, but still have a self-scaled plot. For example, BPARM =
3, 1, -1, 0, 0, 1.0, 10000 will plot amplitudes >= 1.0 against uv
distance, but the amplitude scale will only go up to the peak amplitude
in the data not to 10000 Jy. The X axis (uv distance) will self-scale
to cover the full range.
XINC :
Allows plotting of only every XINC'th point. The plotting of the
plot file can be extremely tiresome unless the number of points is
limited. A few thousand is usually reasonable.
REFERENCES
None.
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