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casa
$Rev:20696$
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casa
$Rev:20696$
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Functions | |
| def | sdgrid |
| def sdgrid.sdgrid | ( | infiles = [""], |
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antenna = -1, |
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scanlist = [], |
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ifno = -1, |
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pollist = [], |
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gridfunction = 'BOX', |
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convsupport = -1, |
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truncate = -1, |
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gwidth = -1, |
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jwidth = -1, |
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weight = 'UNIFORM', |
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clipminmax = False, |
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outfile = '', |
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overwrite = False, |
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npix = -1, |
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cell = '', |
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center = '', |
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plot = False |
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| ) |
SD task: gridding single dish data
Keyword arguments:
infiles -- name of input SD dataset. can be list.
example: 'testimage.asap'
['testimage1.asap','testimage2.asap']
antenna -- select data based on antenna name(s) or id(s)
default: -1
example: 0, 'DV01'
scanlist -- list of scan numbers to process
default: [] (use all scans)
example: [21,22,23,24]
ifno -- IFNO to be gridded
default: -1 (only process IFNO in the first row)
example: 1
pollist -- POLNO to be gridded
default: [] (all polarizations)
example: 1,[0,1]
gridfunction -- gridding function
options: 'BOX' (Box-car), 'SF' (Spheroidal),
'GAUSS' (Gaussian), 'PB' (Primary-beam)
'GJINC' (Gaussian*Jinc)
default: 'BOX'
example: 'SF'
>>> gridfunction expandable parameter:
convsupport -- convolution support for 'SF'
default: -1 (use default for each gridfunction)
example: 3
truncate -- truncattion radius of convolution kernel.
effective only for 'GAUSS' and 'GJINC'.
default: '-1' (use default for each gridfunction)
example: 3, '20arcsec', '3pixel'
gwidth -- HWHM for gaussian. Effective only for
'GAUSS' and 'GJINC'.
default: '-1' (use default for each gridfunction)
example: 3, '20arcsec', '3pixel'
jwidth -- Width of jinc function. Effective only for
'GJINC'.
default: '-1' (use default for each gridfunction)
example: 3, '20arcsec', '3pixel'
weight -- weight type (both lower-case and upper-case are
acceptable)
options: 'UNIFORM',
'TSYS' (1/Tsys**2 weighted)
'TINT' (integration time weighted)
'TINTSYS' (Tint/Tsys**2)
default: 'UNIFORM'
clipminmax -- do min/max cliping if True
default: False
outfile -- output data name
default: '' (outfile will be set to infile+'.grid')
example: 'mydata.asap.grid'
overwrite -- overwrite option for outfile
default: False (not overwrite)
options: True, False
example: if True, existing file will be overwritten
npix -- x and y image size in pixels, symmetric for single value
default: -1 (automatically calculated from cell size and
the data)
example: npix=200 (equivalent to [200,200])
cell -- x and y cell size. default unit arcsec
default: '' (automatically calculated from npix if it is
set, otherwise '1.0arcmin')
example: cell=['0.2arcmin, 0.2arcmin']
cell='0.2arcmin' (equivalent to example above)
cell=12.0 (interpreted as '12.0arcsec'='0.2arcmin')
center -- grid center
default: '' (automatically calculated from the data)
example: 'J2000 13h44m00 -17d02m00'
['05:34:48.2', '-05.22.17.7'] (in J2000 frame)
[1.46, -0.09] (interpreted as radian in J2000 frame)
plot -- Plot result or not
default: False (not plot)
example: if True, result will be plotted
DESCRIPTION:
The sdgrid task performs spatial gridding according to the user
specification of spatial grid, convolution function, etc.
For grid configuration, the task supplements necessary information
by referring input data if any of gridding parameter ('npix',
'cell', or 'center') is not specified by the user. If 'center' is
default value (empty string), central position of the grid will be
set to the center of observed area, i.e. x=0.5*(xmax+xmin),
y=0.5*(ymax+ymin). If either 'cell' or 'npix' is set, unspecified
one will be calculated from the others. In that case, total extent of
the grid will be set to cover all observed position. If neither 'cell'
nor 'npix' is set, cell size will be set to 1.0 arcmin and number of
pixel will be calculated based on that cell size.
Currently, only J2000 frame is supported.
The parameter gridfunction sets gridding function for imaging.
Currently, the task supports 'BOX' (Box-car), 'SF' (Prolate
Spheroidal Wave Function), 'GAUSS' (Gaussian), 'GJINC' (Gaussian*
Jinc), where Jinc(x) = J_1(pi*x/c)/(pi*x/c) with a first order
Bessel function J_1, and 'PB' (Primary Beam, not implemented yet).
For 'PB', correct antenna informations should be included in input
file.
There are four subparameters for gridfunction: convsupport, truncate,
gwidth, and jwidth. The convsupport is an integer specifying cut-off
radius for 'SF' in units of pixel. By default (convsupport=-1),
the cut-off radius is set to 3 pixels. The truncate is a cut-off
radius for 'GAUSS' or 'GJINC'. It accepts integer, float, and
string values of numeric plus unit. Allowed units are angular
units such as 'deg', 'arcmin', 'arcsec', and 'pixel'. Default unit
is 'pixel' so that string without unit or numerical values (integer
or float) will be interpreted as radius in pixel. Default value
for truncate, which is used when negative radius is set, is 3*HWHM
for 'GAUSS' and radius at first null for 'GJINC'. The gwidth is
the HWHM of gaussian for 'GAUSS' and 'GJINC'. Default value is
sqrt(log(2)) pixel for 'GAUSS' and 2.52*sqrt(log(2)) pixel for
'GJINC'. The jwidth specifies width of the jinc function (parameter
'c' in the definition above). Default is 1.55 pixel. Both gwidth
jwidth allows integer, float, or string of numeric plus unit.
Default values for gwidth and jwidth are taken from Mangum et al.
(2007).
Boolean parameter 'plot' controls whether gridded result is plotted
or not. If True, color map of gridded data will be shown. Pixel
center and observed position are overlayed as blue dot and red dot,
respectively. Currently, channel averaged value will be plotted.Definition at line 13 of file sdgrid.py.
References task_sdgrid.sdgrid(), and vla_uvfits_line_sf.verify.
1.8.0