def _checkfile(filename, datacolumn):
import re
# Currently this supports only ms files
# As such there is no reason to check filetype.
# If it cannot be opened as ms it will not be supported.
# if re.match('^.*[mM][sS]/*$', filename) is not None:
try:
from taskinit import ms
ms.open(filename)
ms.done()
except ImportError:
# This probably means that it was run from a pure python session.
# We will relegate any checks that it is a valid ms file to the
# stacker.
if not os.access(filename, os.F_OK):
raise RuntimeError(
'Could not find data file "{}".'.format(filename))
filename = filename
filetype = FILE_TYPE_MS
fileoptions = 0
if datacolumn == 'data':
fileoptions = MS_DATACOLUMN_DATA
elif datacolumn == 'model' or datacolumn == 'model_data':
fileoptions = MS_MODELCOLUMN_DATA
# elif re.match('^.*[fF][iI][tT][sS]$', filename) is not None:
# raise NotImplementedError('FITS format is currently not supported.')
return filetype, filename, fileoptions
def get_phs_center(msfile):
""" get the phase center of the MS file using CASA taskinit.ms
Parameters
----------
msfile: str
measurement set filename
Returns
-------
pcd:
phase center
Note
----
may need further modification if nField > 1 unless it is the same for all fields (need further investigation)
"""
from taskinit import ms
ms.open(msfile)
pc = ms.getfielddirmeas()
if not isinstance(pc, dict) is True:
pc()
epoch = pc['refer']
pcd_dec = pc['m1']['value'] * 180 / np.pi
pcd_ra = pc['m0']['value'] * 180 / np.pi
if pcd_ra < 0:
pcd_ra += 360
ms.done()
pcd = [pcd_ra, pcd_dec]
return pcd
def MSpcd2(msFile):
"""using CASA taskinit.ms
Parameters
----------
msFile: string
measurement set filename
Returns
-------
pcd:
phase center
Note
----
may need further modification if nField > 1
unless it is the same for all fields
(need further investigation)
"""
from taskinit import ms
ms.open(msFile)
pc = ms.getfielddirmeas()
if not isinstance(pc, dict) is True:
pc()
epoch = pc['refer']
pcd_dec = pc['m1']['value'] * 180 / numpy.pi
pcd_ra = pc['m0']['value'] * 180 / numpy.pi
if pcd_ra < 0:
pcd_ra += 360
ms.done()
pcd = [pcd_ra, pcd_dec]
return pcd
def checkMS(msFile, cont=True):
""" get the number of spw and channels in the measurement set
for continuum: combine into 1 channel and spw before running uvmcmcfit
Parameters
----------
msFile: string
CASA measurement set
Returns
-------
nspw:
number of spw
nchan:
number of channels
"""
from taskinit import ms
ms.open(msFile)
metadata = ms.metadata()
ms.done()
nspw = metadata.nspw()
for i in range(nspw):
# number of channels in each spw
nchan = metadata.nchan(spw)
metadata.done()
return nspw, nchan
def make_pbfile(vis, pbfile):
from taskinit import im, ms, ia, qa, tb
import numpy as np
from scipy.constants import c
ms.open(vis)
fields = ms.range('field_id')['field_id']
ms.done()
im.open(vis)
im.selectvis(field=fields[0])
ms.open(vis)
freq = np.mean(ms.range('chan_freq')['chan_freq'])
phase_dir = ms.range('phase_dir')['phase_dir']['direction']
ms.done()
phase_dir = phase_dir[0][0], phase_dir[1][0]
phase_dir = [
qa.formxxx(str(phase_dir[0]) + 'rad', format='hms'),
qa.formxxx(str(phase_dir[1]) + 'rad', format='dms')
]
phase_dir = 'J2000 ' + ' '.join(phase_dir)
tb.open(vis + '/ANTENNA/')
dishdia = np.min(tb.getcol('DISH_DIAMETER'))
tb.done()
# pb of 512 pix cover pb down to 0.001
# ensure largest pixel to pixel var to .01
minpb = 0.001
nx = 512
cellconv = (nx * np.sqrt(np.log(2) / np.log(1 / minpb)))**-1
beam = c / freq / dishdia
cell = {}
cell['value'] = beam * cellconv
cell['unit'] = 'rad'
# nx = int(3*3e8/freq/dishdia*1.22*180/
# math.pi*3600/qa.convert(advise['cell'],
# 'arcsec')['value'])
# Chosen as to be 3 times fwhm of primary beam,
# should include up to approximately .01 of peak flux
im.defineimage(nx=nx, ny=nx, cellx=cell, celly=cell, phasecenter=phase_dir)
im.setvp(dovp=True)
im.makeimage(type='pb', image=pbfile)
im.done()
ia.open(pbfile)
cs = ia.coordsys()
cs.setreferencevalue(type='direction', value=[0., 0.])
ia.setcoordsys(cs.torecord())
ia.maskhandler('delete', 'mask0')
ia.done()
def guesspb(vis):
"""
Produces a PrimaryBeamModel from a measurementset
"""
print(vis)
from taskinit import ms, tb, qa
ms.open(vis)
freq = (np.mean(ms.range('chan_freq')['chan_freq']) / 1e9)
ms.done()
tb.open(vis + '/OBSERVATION')
telescope = tb.getcol('TELESCOPE_NAME')[0]
tb.done()
pbfile = '{0}-{1:.1f}GHz.pb'.format(telescope, freq)
print(pbfile)
if not os.access(pbfile, os.F_OK):
stacker.make_pbfile(vis, pbfile)
return MSPrimaryBeamModel(pbfile)