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def | __init__ |
def | __call__ |
Private Attributes | |
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__doc__ | |
Static Private Attributes | |
string | __name__ |
Definition at line 18 of file cvel_pg.py.
def cvel_pg.cvel_pg_.__init__ | ( | self | ) |
Definition at line 21 of file cvel_pg.py.
def cvel_pg.cvel_pg_.__call__ | ( | self, | |
vis = None , |
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outputvis = None , |
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passall = None , |
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field = None , |
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spw = None , |
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selectdata = None , |
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antenna = None , |
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timerange = None , |
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scan = None , |
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array = None , |
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mode = None , |
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nchan = None , |
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start = None , |
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width = None , |
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interpolation = None , |
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phasecenter = None , |
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restfreq = None , |
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outframe = None , |
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veltype = None , |
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hanning = None , |
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async = None |
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) |
regrid an MS to a new spectral window / channel structure or frame vis -- Name of input visibility file default: none; example: vis='ngc5921.ms' outputvis -- Name of output measurement set (required) default: none; example: vis='ngc5921-regridded.ms' passall -- if False, data not meeting the selection is omitted/deleted or flagged (if in-row); if True, data not meeting the selection on field and spw is passed through without modification default: False; example: field='NGC5921' passall=False : only data from NGC5921 is included in output MS, no data from other fields (e.g. 1331+305) is included passall=True : data from NGC5921 is transformed by cvel, all other fields are passed through unchanged field -- Select fields in mosaic. Use field id(s) or field name(s). ['go listobs' to obtain the list id's or names] default: ''= all fields If field string is a non-negative integer, it is assumed to be a field index otherwise, it is assumed to be a field name field='0~2'; field ids 0,1,2 field='0,4,5~7'; field ids 0,4,5,6,7 field='3C286,3C295'; field named 3C286 and 3C295 field = '3,4C*'; field id 3, all names starting with 4C spw --Select spectral window/channels NOTE: This selects the data passed as the INPUT to mode default: ''=all spectral windows and channels spw='0~2,4'; spectral windows 0,1,2,4 (all channels) spw='0:5~61'; spw 0, channels 5 to 61 spw='<2'; spectral windows less than 2 (i.e. 0,1) spw='0,10,3:3~45'; spw 0,10 all channels, spw 3, channels 3 to 45. spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each. spw='0:0~10;15~60'; spectral window 0 with channels 0-10,15-60 spw='0:0~10,1:20~30,2:1;2;3'; spw 0, channels 0-10, spw 1, channels 20-30, and spw 2, channels, 1,2 and 3 selectdata -- Other data selection parameters default: True >>> selectdata=True expandable parameters antenna -- Select data based on antenna/baseline default: '' (all) If antenna string is a non-negative integer, it is assumed to be an antenna index, otherwise, it is considered an antenna name. antenna='5&6'; baseline between antenna index 5 and index 6. antenna='VA05&VA06'; baseline between VLA antenna 5 and 6. antenna='5&6;7&8'; baselines 5-6 and 7-8 antenna='5'; all baselines with antenna index 5 antenna='05'; all baselines with antenna number 05 (VLA old name) antenna='5,6,9'; all baselines with antennas 5,6,9 index numbers timerange -- Select data based on time range: default = '' (all); examples, timerange = 'YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss' Note: if YYYY/MM/DD is missing date defaults to first day in data set timerange='09:14:0~09:54:0' picks 40 min on first day timerange= '25:00:00~27:30:00' picks 1 hr to 3 hr 30min on NEXT day timerange='09:44:00' pick data within one integration of time timerange='>10:24:00' data after this time scan -- Scan number range. default: '' (all) example: scan='1~5' Check 'go listobs' to insure the scan numbers are in order. array -- Select data by (sub)array indices default: '' (all); example: array='0~2'; arrays 0 to 2 mode -- Frequency Specification: NOTE: See examples below: default: 'channel' mode = 'channel'; Use with nchan, start, width to specify output spw. Produces equidistant grid based on first selected channel. See examples below. mode = 'velocity', means channels are specified in velocity. mode = 'frequency', means channels are specified in frequency. mode = 'channel_b', alternative 'channel' mode. Does not force an equidistant grid. Faster. >>> mode expandable parameters Start, width are given in units of channels, frequency or velocity as indicated by mode nchan -- Number of channels in output spw default: -1 = all channels; example: nchan=3 start -- Start or end input channel (zero-based) depending on the sign of the width parameter default=0; example: start=5 width -- Output channel width in units of the input channel width (sign indicates whether the start parameter is lower(+) or upper(-) end of the range) default=1; example: width=4 interpolation -- Interpolation method (linear, nearest, cubic, spline, fftshift) default = 'linear' examples: spw = '0,1'; mode = 'channel' will produce a single spw containing all channels in spw 0 and 1 spw='0:5~28^2'; mode = 'channel' will produce a single spw made with channels (5,7,9,...,25,27) spw = '0'; mode = 'channel': nchan=3; start=5; width=4 will produce an spw with 3 output channels new channel 1 contains data from channels (5+6+7+8) new channel 2 contains data from channels (9+10+11+12) new channel 3 contains data from channels (13+14+15+16) spw = '0:0~63^3'; mode='channel'; nchan=21; start = 0; width = 1 will produce an spw with 21 channels new channel 1 contains data from channel 0 new channel 2 contains data from channel 2 new channel 21 contains data from channel 61 spw = '0:0~40^2'; mode = 'channel'; nchan = 3; start = 5; width = 4 will produce an spw with three output channels new channel 1 contains channels (5,7) new channel 2 contains channels (13,15) new channel 3 contains channels (21,23) phasecenter -- direction measure or fieldid for the mosaic center default: '' => first field selected ; example: phasecenter=6 or phasecenter='J2000 19h30m00 -40d00m00' restfreq -- Specify rest frequency to use for output image default='' Occasionally it is necessary to set this (for example some VLA spectral line data). For example for NH_3 (1,1) put restfreq='23.694496GHz' outframe -- output reference frame default='' (keep original reference frame) ; example: outframe='bary' veltype -- definition of velocity (in mode) default = 'radio' hanning -- if true, Hanning smooth frequency channel data to remove Gibbs ringing ================================================================== The intent of cvel is to transform channel labels and the visibilities to a spectral reference frame which is appropriate for the science analysis, e.g. from TOPO to LSRK to correct for Doppler shifts throughout the time of the observation. Naturally, this will change the shape of the spectral feature to some extent. According to the Nyquist theorem you should oversample a spectrum with twice the numbers of channels to retain the shape. Based on some tests, however, we recommend to observe with at least 3-4 times the number of channels for each significant spectral feature (like 3-4 times the linewidth). This will minimize regridding artifacts in cvel. If cvel has already established the grid that is desired for the imaging, clean should be run with exactly the same frequency/velocity parameters as used in cvel in order to avoid additional regridding in clean. Hanning smoothing is optionally offered in cvel, but tests have shown that already the regridding process itself, if it involved a transformation from TOPO to a non-terrestrial reference frame, implies some smoothing (due to channel interpolation) such that Hanning smoothing may not be necessary.
Definition at line 26 of file cvel_pg.py.
References vla_uvfits_line_sf.verify.
cvel_pg.cvel_pg_.__bases__ [private] |
Definition at line 22 of file cvel_pg.py.
cvel_pg.cvel_pg_.__doc__ [private] |
Definition at line 23 of file cvel_pg.py.
string cvel_pg.cvel_pg_.__name__ [static, private] |
Definition at line 19 of file cvel_pg.py.