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8.2.1.17 sdtpimaging
infile -- name of input SD (MS) dataset
calmode -- calibration mode (currently only baseline subtraction)
options: ’baseline’,’none’
default: ’none’
example: choose mode ’none’ if you have
already calibrated and want to do
plotting nd/or imaging
>>> calmode=’baseline’ expandable parameters
masklist -- mask in numbers of rows from each edge of each scan
to be included for baseline fitting
default: none
example: [30,30] or [30]
used first 30 rows and last 30 rows of each scan for
the baseline
blpoly -- polynomial order for the baseline fit
default: 1
backup -- set True to create backup for input data
default: True
flaglist -- list of scan numbers to flag (ranges can be accepted)
default: [] (use all scans)
example: [[0,3],80]
flag the scan range [0,3] = [0,1,2,3] and scan 80
antenna -- select data based on antenna name(s) or id(s) in string
default: ’’ (use all antennas)
example: ’0,1’, ’DV01’
WARNING: currently baseline subtraction properly
only one of the antennas.
stokes -- select data based on stokes or polarization type
default: ’’ (use all polarizations)
example: ’XX’
createimage -- do imaging?
default: False
>>> createimage=True expandable parameters
outfile -- output image name
default: none
example: ’mySDimage.im’
imsize -- x and y image size in pixels, symmetric for single
value
default: [256,256]
example: imsize=200 (equivalent to [200,200])
cell -- x and y cell size. default unit arcmin
default: ’1.0arcmin’
example: cell=[’0.2arcmin, 0.2arcmin’]
cell=’0.2arcmin’ (equivalent to example above)
phasecenter -- image phase center: direction measure or fieldid
default: 0
example: ’J2000 13h44m00 -17d02m00’, ’AZEL -123d48m29 15d41m41’
ephemsrcname -- ephemeris source name to proper shifting to
center on the moving source for imaging
default: ’’
if the source name in the data matches one of the
known solar objects by the system, this task
automatically set the source name.
example: ’moon’
pointingcolumn -- pointing data column to use
option: ’direction’, ’target’, ’pointing_offset’,
’source_offset’, ’encoder’
default: ’direction’
gridfunction -- gridding function for imaging
options: ’BOX’ (Box-car), ’SF’ (Spheroidal),
’PB’ (Primary-beam)
default: ’BOX’
example: ’SF’
plotlevel -- control for plotting of results
options: (int) 0=none, 1=some, 2=more, <0=hardcopy
default: 0 (no plotting)
example: plotlevel<0 as abs(plotlevel), e.g.
-1: hardcopy plot
(will be named <infile>_scans.eps)
1: plot raw data, calibrated data
(for calmode=’baseline)
plot raw or if exist calibrated data
(for calmode=’none’)
2: plot raw data, progressively display baseline
fitting for each scan, and final calibrated data
(for calmode=’baseline’)
DESCRIPTION:
Task sdtpimaging performs data selection, calibration, and imaging for single-dish totalpower raster scan data. This is a still experimental task made to work for the data taken at the ALMA Testing Facility (ATF) and OSF. Currently, this task directly accesses the Measurement Set data because of the data access efficiency. So it differs from other single-dish tasks that mostly operate on the ASAP scantable data format. By setting calmode=’none’, one can run sdtpimaging to plot the data (raw or calibrated, if exists) and further imaging by setting createimage=True. The calibration available at this moment is just a simple baseline subtraction for each scan. The fitted regions set by masklist are the common for all the scans. Selection of the antennas can be made by setting antenna ID(s) or antenna name(s) in string (e.g. ’0’, ’0,1’, ’DV01’,etc.). For baseline subtraction, it currently works properly for a single antenna selection. So a separate sdtpimaging task needs to be run for each antenna. It currently assumes that the data has a single spw(=0) and fieldid(=0). By setting flaglist, one can set flag by scan numbers to be excluded from imaging. (Note: ’scan numbers’ are determined from state id and related to SUB_SCAN column in STATE subtable and they are typically different from SCAN_NUMBER in MS.) By default, baseline subtraction stage overwrites (FLOAT_)DATA column of input data. You can keep original data by setting backup parameter to True. In this case, the task make a copy of input data specified by infile parameter. Name of backup file is ¡infile¿.sdtpimaging.bak.¡timestamp¿. The selection of polarizations can be made by specifying the polarization name in stokes, such as ’XX’ or ’YY’ for linear polarizations. For example, with createimage=True, stokes=’XXYY’ will produces an image cube with each plane contains the image of one of the polarizations while stokes=’’ or stokes=’I’ will produces a ’total intensity’ or Stokes I image. Among the imaging sub-parameters, ephemsrcname is used to set the name of a moving source such as planets to produce a stationary image (can be omitted), and pointingcolumn is used to specify which pointing data column to use for imaging.
More information about CASA may be found at the
CASA web page
Copyright © 2010 Associated Universities Inc., Washington, D.C.
This code is available under the terms of the GNU General Public Lincense
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