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| == Help on cvel task: ==
| | {{cvel}} |
| <pre>
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| regrid an MS to a new spectral window / channel structure or frame
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| vis -- Name of input visibility file
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| default: none; example: vis='ngc5921.ms'
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| outputvis -- Name of output measurement set (required)
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| default: none; example: vis='ngc5921-regridded.ms'
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| passall -- if False, data not meeting the selection is omitted/deleted
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| or flagged (if in-row); if True, data not meeting the selection
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| on field and spw is passed through without modification
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| default: False; example:
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| field='NGC5921'
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| passall=False : only data from NGC5921 is included in output MS,
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| no data from other fields (e.g. 1331+305) is included
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| passall=True : data from NGC5921 is transformed by cvel, all other
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| fields are passed through unchanged
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| field -- Select fields in mosaic. Use field id(s) or field name(s).
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| ['go listobs' to obtain the list id's or names]
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| default: ''= all fields
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| If field string is a non-negative integer, it is assumed to
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| be a field index otherwise, it is assumed to be a
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| field name
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| field='0~2'; field ids 0,1,2
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| field='0,4,5~7'; field ids 0,4,5,6,7
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| field='3C286,3C295'; field named 3C286 and 3C295
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| field = '3,4C*'; field id 3, all names starting with 4C
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| spw --Select spectral window/channels
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| NOTE: This selects the data passed as the INPUT to mode
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| default: ''=all spectral windows and channels
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| spw='0~2,4'; spectral windows 0,1,2,4 (all channels)
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| spw='0:5~61'; spw 0, channels 5 to 61
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| spw='<2'; spectral windows less than 2 (i.e. 0,1)
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| spw='0,10,3:3~45'; spw 0,10 all channels, spw 3,
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| channels 3 to 45.
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| spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each.
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| spw='0:0~10;15~60'; spectral window 0 with channels
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| 0-10,15-60
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| spw='0:0~10,1:20~30,2:1;2;3'; spw 0, channels 0-10,
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| spw 1, channels 20-30, and spw 2, channels, 1,2 and 3
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| selectdata -- Other data selection parameters
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| default: True
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| >>> selectdata=True expandable parameters
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| antenna -- Select data based on antenna/baseline
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| default: '' (all)
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| If antenna string is a non-negative integer, it is
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| assumed to be an antenna index, otherwise, it is
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| considered an antenna name.
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| antenna='5&6'; baseline between antenna index 5 and
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| index 6.
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| antenna='VA05&VA06'; baseline between VLA antenna 5
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| and 6.
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| antenna='5&6;7&8'; baselines 5-6 and 7-8
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| antenna='5'; all baselines with antenna index 5
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| antenna='05'; all baselines with antenna number 05
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| (VLA old name)
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| antenna='5,6,9'; all baselines with antennas 5,6,9
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| index numbers
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| timerange -- Select data based on time range:
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| default = '' (all); examples,
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| timerange = 'YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss'
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| Note: if YYYY/MM/DD is missing date defaults to first
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| day in data set
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| timerange='09:14:0~09:54:0' picks 40 min on first day
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| timerange= '25:00:00~27:30:00' picks 1 hr to 3 hr
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| 30min on NEXT day
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| timerange='09:44:00' pick data within one integration
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| of time
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| timerange='>10:24:00' data after this time
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| scan -- Scan number range.
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| default: '' (all)
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| example: scan='1~5'
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| Check 'go listobs' to insure the scan numbers are in
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| order.
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| array -- Select data by (sub)array indices
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| default: '' (all); example:
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| array='0~2'; arrays 0 to 2
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| mode -- Frequency Specification:
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| NOTE: See examples below:
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| default: 'channel'
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| mode = 'channel'; Use with nchan, start, width to specify
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| output spw. Produces equidistant grid based on first
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| selected channel. See examples below.
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| mode = 'velocity', means channels are specified in
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| velocity.
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| mode = 'frequency', means channels are specified in
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| frequency.
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| mode = 'channel_b', alternative 'channel' mode.
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| Does not force an equidistant grid. Faster.
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| >>> mode expandable parameters
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| Start, width are given in units of channels, frequency
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| or velocity as indicated by mode
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| nchan -- Number of channels in output spw
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| default: -1 = all channels; example: nchan=3
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| start -- Start input channel (relative-0)
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| default=0; example: start=5
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| width -- Output channel width in units of the input
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| channel width (>1 indicates channel averaging)
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| default=1; example: width=4
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| interpolation -- Interpolation method
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| default = 'linear'
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| examples:
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| spw = '0,1'; mode = 'channel'
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| will produce a single spw containing all channels in spw
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| 0 and 1
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| spw='0:5~28^2'; mode = 'channel'
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| will produce a single spw made with channels
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| (5,7,9,...,25,27)
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| spw = '0'; mode = 'channel': nchan=3; start=5; width=4
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| will produce an spw with 3 output channels
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| new channel 1 contains data from channels (5+6+7+8)
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| new channel 2 contains data from channels (9+10+11+12)
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| new channel 3 contains data from channels (13+14+15+16)
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| spw = '0:0~63^3'; mode='channel'; nchan=21; start = 0;
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| 0 and 1
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| spw='0:5~28^2'; mode = 'channel'
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| will produce a single spw made with channels
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| (5,7,9,...,25,27)
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| spw = '0'; mode = 'channel': nchan=3; start=5; width=4
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| will produce an spw with 3 output channels
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| new channel 1 contains data from channels (5+6+7+8)
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| new channel 2 contains data from channels (9+10+11+12)
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| new channel 3 contains data from channels (13+14+15+16)
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| spw = '0:0~63^3'; mode='channel'; nchan=21; start = 0;
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| width = 1
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| will produce an spw with 21 channels
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| new channel 1 contains data from channel 0
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| new channel 2 contains data from channel 2
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| new channel 21 contains data from channel 61
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| spw = '0:0~40^2'; mode = 'channel'; nchan = 3; start =
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| 5; width = 4
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| will produce an spw with three output channels
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| new channel 1 contains channels (5,7)
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| new channel 2 contains channels (13,15)
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| new channel 3 contains channels (21,23)
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| phasecenter -- direction measure or fieldid for the mosaic center
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| default: '' => first field selected ; example: phasecenter=6
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| or phasecenter='J2000 19h30m00 -40d00m00'
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| restfreq -- Specify rest frequency to use for output image
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| default='' Occasionally it is necessary to set this (for
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| example some VLA spectral line data). For example for
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| NH_3 (1,1) put restfreq='23.694496GHz'
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| outframe -- output reference frame
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| default='' (keep original reference frame) ; example: outframe='bary'
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| veltype -- definition of velocity (in mode)
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| default = 'radio'
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| hanning -- if true, Hanning smooth frequency channel data to remove Gibbs ringing
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| </pre>
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