split – Create a visibility subset from an existing visibility set – manipulation task

Description

The old implementation is available for a short time as oldsplit.
Task split2 has been renamed to split. The split2 alias will be removed soon.
Please, update your scripts to call split instead.

This new split task uses the MSTransform framework underneath. Split is the general purpose program to make a new data set that is a subset or averaged form of an existing data set. General selection parameters are included, and one or all of the various data columns (DATA, LAG_DATA and/or FLOAT_DATA, MODEL_DATA and/or CORRECTED_DATA) can be selected.

Split is often used after the initial calibration of the data to make a smaller Measurement Set with only the data that will be used in further flagging, imaging and/or self-calibration. Split can average over frequency (channels) and time (integrations).

Split also supports the Multi-MS (MMS) format as input. For more information about MMS, see the help of partition and mstransform.

Parameters

Title
Parameter	Default	Description
vis	`''`
outputvis	`''`
keepmms	`True`
field	`''`
spw	`''`
scan	`''`
antenna	`''`
correlation	`''`
timerange	`''`
intent	`''`
array	`''`
uvrange	`''`
observation	`''`
feed	`''`
datacolumn	`'corrected'`
keepflags	`True`
width	`int(1)`
timebin	`'0s'`
combine	`''`

Parameter Explanations

vis

''

Name of input Measurement set or Multi-MS

outputvis

''

Name of output Measurement set or Multi-MS

keepmms

True

If the input is a Multi-MS the output will also be a Multi-MS.

field

''

Select field using ID(s) or name(s).

spw

''

Select spectral window/channels.

scan

''

Select data by scan numbers.

antenna

''

Select data based on antenna/baseline.

correlation

''

Correlation: ‘’ ==> all, correlation=”XX,YY”.

timerange

''

Select data by time range.

intent

''

Select data by scan intent.

array

''

Select (sub)array(s) by array ID number.

uvrange

''

Select data by baseline length.

observation

''

Select by observation ID(s).

feed

''

Multi-feed numbers: Not yet implemented.

datacolumn

'corrected'

Which data column(s) to process.

keepflags

True

Keep completely flagged rows instead of dropping them.

width

int(1)

Number of channels to average to form one output channel

timebin

'0s'

Bin width for time averaging

combine

''

Span the timebin across scan, state or both