Split

Help on split task:

Create a visibility subset from an existing visibility set


     Split is the general purpose program to make a new data set
     that is a subset of an existing data set.  General selection parameters
     are included, and any combination of the three data columns (data, model
     and/or corrected) can be selection.

     Split is often used after the initial calibration of the data to remove those
     sources which need additional flagging, imaging and self-calibration.  The data
     can be averaged over specified frequency channels of the input data set and time
     averaging is also available.  

    Note: It is not yet possible to simultaneously average a data set in time and frequency
    in one execution:  they must be done separately.


        Keyword arguments:
        vis -- Name of input visibility file
                default: none; example: vis='ngc5921.ms'
        outputvis -- Name of output visibility file
                default: none; example: outputvis='ngc5921_src.ms'

        datacolumn -- Which data column to split out
                default='corrected'; example: datacolumn='data'
                Options: 'data', 'model', 'corrected', 'all',
                'data,model','data,corrected','model,corrected',
                note: 'all'='data,model,corrected' 

        --- Data Selection (see help par.selectdata for more detailed
            information)

        field -- Select field using field id(s) or field name(s).
                  [run 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 adn 3C295
               field = '3,4C*'; field id 3, all names starting with 4C
        spw -- Select spectral window/channels
               default: ''=all spectral windows and channels
               spw='0~2,4'; spectral windows 0,1,2,4 (all channels)
               spw='<2';  spectral windows less than 2 (i.e. 0,1)
               spw='0:5~61'; spw 0, channels 5 to 61
               spw='0,10,3:3~45'; spw 0,10 all channels, spw 3 - chans 3 to 45.
               spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each.
               spw = '*:3~64'  channels 3 through 64 for all sp id's
                       spw = ' :3~64' will NOT work.
               spw = '*:0;60~63'  channel 0 and channels 60 to 63 for all IFs 
                      ';' needed to separate different channel ranges in one spw
               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;4'; spw 0, channels 0-10,
                        spw 1, channels 20-30, and spw 2, channels, 1, 2 and 4
        width -- Defines the number of channel to average to form the one
                 output channel.
                 default: '1' => no channel averaging
                 example: width=[2,3] => average 2 channels of 1st
                          spectral window selected and 3 in the second one.
        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 assumed to be 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'; baseline 5-6 and 7-8
               antenna='5'; all baselines with antenna 5
               antenna='5,6,10'; all baselines with antennas 5 and 6
        timebin -- Value for time averaging.
                default='0s' (no averaging); example: timebin='30s'
                example '10' means '10s' 
        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, timerange defaults to the
               first day in the dataset
               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' data within one integration of time
               timerange='>10:24:00' data after this time
        array  -- (Sub)array number range
            default: ''=all
        uvrange -- Select data within uvrange (default units meters)
            default: ''=all; example:
            uvrange='0~1000klambda'; uvrange from 0-1000 kilo-lambda
            uvrange='>4klambda';uvranges greater than 4 kilo-lambda
            uvrange='0~1000km'; uvrange in kilometers
        scan -- Scan number range
            default: ''=all