Manual flagging and clipping in flagdata

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3.6.1.1 Manual flagging and clipping in flagdata

Manualflag and clipping have been separated in flagdata2. They are controlled by separated parameters, manualflag=True and clip=True and contain there own sub-parameters:

manualflag          =       True        #  Flag by antenna, time, field, etc.
     mf_field       =         ’’        #  Field names or field index numbers: ’’==>all,
                                        #   field=’0~2,3C286’
     mf_spw         =         ’’        #  spectral-window/frequency/channel
     mf_antenna     =         ’’        #  antenna/baselines: ’’==>all, antenna = ’3,VA04’
     mf_timerange   =         ’’        #  time range: ’’==>all, timerange=’09:14:0~09:54:0’
     mf_scan        =         ’’        #  scan numbers: ’’==>all
     mf_intent      =         ’’        #  observation intent: ’’==>all
     mf_feed        =         ’’        #  multi-feed numbers: Not yet implemented
     mf_array       =         ’’        #  (sub)array numbers: ’’==>all
     mf_uvrange     =         ’’        #  uv range: ’’==>all; uvrange = ’0~100klambda’, default
                                        #   units=meters
     mf_observation =         ’’        #  Select data based on observation ID: ’’==>all

clip                =       True        #  Clip data according to value
     clipexpr       =   ’ABS RR’        #  Expression to clip on
     clipminmax     =         []        #  Range to use for clipping
     clipcolumn     =     ’DATA’        #  Data column to use for clipping
     clipoutside    =       True        #  Clip outside the range, or within it
     channelavg     =      False        #  Average over channels (scalar average)

The following commands give the results shown in Figure 3.9:

  plotxy(’ngc5921.ms’,’uvdist’)
  flagdata2(vis=’ngc5921.ms’,clip=True, clipexpr=’LL’,clipminmax=[0.0,1.6],clipoutside=True)
  plotxy(’ngc5921.ms’,’uvdist’)

Figure 3.9: tflagdata: Flagging example using the clip mode.

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The channelavg toggle (new in Version 3.0.0) is now available to (vector) average the data over all channels before doing the clipping test. This is most useful when flagging on phase stable or corrected data (e.g. after applycal and split to a new dataset).

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