.. _Filter.json#/:

Filter
======

"Filter on baseline and/or channel (only the given baselines/channels are kept). The reader step has an implicit filter."


.. _Filter.json#/inputs:

inputs
******


.. _Filter.json#/inputs/type:

type
++++

:type: ``string``

:default: ``filter``

:doc: Case-insensitive step type; must be 'filter' `.`


.. _Filter.json#/inputs/baseline:

baseline
++++++++

:type: ``string``

:default: ``""``

:doc: Baseline to keep using a selection string. See :ref:`Description of baseline selection parameters`.


.. _Filter.json#/inputs/blrange:

blrange
+++++++

:type: ``array``

:default: ``""``

:doc: Baseline to keep using a range. See :ref:`Description of baseline selection parameters`.


.. _Filter.json#/inputs/corrtype:

corrtype
++++++++

:type: ``string``

:default: ``""``

:doc: Correlation type to match? Must be auto, cross, or an empty string `.`


.. _Filter.json#/inputs/nchan:

nchan
+++++

:type: ``integer``

:default: ``0``

:doc: Number of channels to use from the input MS (0 means till the end).  It can be an expression with ``nchan`` (nr of input channels) as  parameter. E.g. ``15*nchan/16``


.. _Filter.json#/inputs/remove:

remove
++++++

:type: ``boolean``

:default: ``False``

:doc: If true, the stations not used in any baseline will be removed from  the ANTENNA subtable and the antenna ids in the main table will be  renumbered accordingly. To have a consistent output MeasurementSet,  other subtables (FEED, POINTING, SYSCAL, LOFAR_ANTENNA_FIELD,  LOFAR_ELEMENT_FAILURE, and QUALITY_BASELINE_STATISTIC) will also  be updated. Note that stations filtered previously (e.g. using  msselect) will also be removed, even if no baseline selection is  done in the filter step `.`


.. _Filter.json#/inputs/startchan:

startchan
+++++++++

:type: ``integer``

:default: ``0``

:doc: First channel to use from the input MS (channel numbers start  counting at 0). Note that skipped channels will not be written  into the output MS. It can be an expression with ``nchan``  (nr of input channels) as parameter. E.g. ``nchan/32`` will be fine for LOFAR observations with 64 and 256 channels.


.. _Filter.json#/inputs/step_name:

step_name
+++++++++

:type: ``string``

:default: ``filter``

:doc: unique name for the step `.`