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0.1.76 msuvbin

Requires:

Synopsis
grid the visibility data onto a defined uniform grid (in the form of an ms); multiple MS’s can be done onto the same grid

Description

msuvbin is a uv gridding task. The use is for large volumes of data (from multiple epochs) that needs to be imaged into one image. One way of proceeding is to image the epochs and average them after wards. Rather than doing this averaging the visibilities on a common uv grid has several convenience advantages like easily doing the proper weighted averaging and imaging. If an output grid already exists and a second ms is gridded on the grid then the output grid parameters is ignored but the existant grid is used.



Arguments





Inputs

vis

Name of input visibility file (MS)

allowed:

string

Default:

field

Field selection of input ms

allowed:

string

Default:

spw

Spw selection

allowed:

string

Default:

taql

TaQl string for data selection

allowed:

string

Default:

outvis

name of output uvgrid

allowed:

string

Default:

phasecenter

phase center of uv grid

allowed:

string

Default:

nx

Number of pixels of grid along the x-axis

allowed:

int

Default:

1000

ny

Number of pixels of grid along the y-axis

allowed:

int

Default:

1000

cell

pixel cell size defined in sky dimension

allowed:

string

Default:

1arcsec

ncorr

number of correlations to store in grid

allowed:

int

Default:

1

nchan

Number of spectral channels in grid

allowed:

int

Default:

1

fstart

Frequency of first spectral channel

allowed:

string

Default:

1GHz

fstep

spectral channel width

allowed:

string

Default:

1kHz

wproject

Do wprojection correction while gridding

allowed:

bool

Default:

False

memfrac

Limit how much of memory to use

allowed:

double

Default:

0.5

Returns
void

Example

 
 
 
 
 
       Keyword arguments:  
       vis -- Name of input visibility file  
              default: none; example: vis=’ngc5921.ms’  
       field -- Field name list  
               default: ’’ ==> all  
               field = ’1328+307’  specifies source ’1328+307’  
               field = ’4’ specified field with index 4  
       spw -- Spw selection  
               default: spw = ’’ (all spw)  
       spw=’2’  
       taql  --TaQl expression for data selection (see http://www.astron.nl/casacore/trunk/casacore/doc/notes/199.html)  
               default taql=’’  
       Example select all data where U > 1 m in the ms  
       taql=’UVW[0] > 1’  
       outvis -- name of output grid  
               default: ’’  The user has to give something here  
       phasecenter -- phasecenter of the grid  
               default= ’’  
                phasecenter=’J2000 18h03m04 -20d00m45.1’  
      nx  -- number of pixels along the x axis of the grid  
               default: 1000  
       nx=1200  
      ny  -- number of pixels along the y axis of the grid  
               default: 1000  
       ny=1200  
       cell -- cellsize of the grid (given in sky units)  
               default: ’1arcsec’  
               cell=’0.1arcsec’  
ncorr -- number of correlation/polarization plane in uv grid (allowed 1, 2, 4)  
               default: 1  
               ncorr=4  
        nchan -- number of spectral channel  
       default: 1  
               nchan=2000  
        fstart -- frequency of the first channel  
               default: ’1GHz’;  User has to give something useful here  
        fstep -- spectral channel width  
               default: ’1kHz’  
        wproject -- do wprojection correction while gridding  
                default: False  
                wproject=True  
        memfrac -- control how much of computer’s memory is available for  gridding  
                default=0.5  
                memfrac=0.9  
 


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