1.3.1.0 ms.selectpolarization

NRAO Home > CASA > CASA Toolkit Reference Manual

ms.selectpolarization - Function

1.3.1 Selection and convertion of polarizations

Description

This function allows you to select a subset of the polarizations in the current measurement set. This function can also setup conversion to different polarization representations.

You specify the polarizations using a string vector. Allowable strings are include I, Q, U, V, RR, RL, LR, LL, XX, YY, XY, YX. These string must be specified in upper case. If the polarizations match those present in the measurement set they will be selected directly, otherwise all polarizations are read and then a conversion step is done. If the conversion cannot be done then an error will be produced when you try to access the data.

This function return True if the selection was successful, and False if not.

You need to call selectinit before calling this function. If you haven’t then selectinit will be called for you with default arguments.

Arguments


Inputs
wantedpol	The polarizations wanted
	allowed:	stringArray
	Default:

Returns
bool

Example

      ms.open("3C273XC1.MS")
      ms.selectinit(datadescid=0)
      ms.selectpolarization(["I","V"])
      rec = ms.getdata("data")

    This example selects all the data from the measurement set where
    the value in the DATA_DESC_ID column is zero. This
    corresponds to a particular spectral window and polarization
    setup. It then selects the I and V polarizations and when the
    getdata function is called the conversion from RR, LL, LR, RL
    polarizations to I and V occurs.

__________________________________________________________________

[next] [prev] [prev-tail] [front] [up]

More information about CASA may be found at the CASA web page

This code is available under the terms of the GNU General Public Lincense