def create_LOFAR_configuration(antfile: str,
meta: dict = None) -> Configuration:
""" Define from the LOFAR configuration file
:param antfile:
:param meta:
:return: Configuration
"""
antxyz = numpy.genfromtxt(antfile,
skip_header=2,
usecols=[1, 2, 3],
delimiter=",")
nants = antxyz.shape[0]
assert antxyz.shape[
1] == 3, "Antenna array has wrong shape %s" % antxyz.shape
anames = numpy.genfromtxt(antfile,
dtype='str',
skip_header=2,
usecols=[0],
delimiter=",")
mounts = numpy.repeat('XY', nants)
location = EarthLocation(x=[3826923.9] * u.m,
y=[460915.1] * u.m,
z=[5064643.2] * u.m)
fc = Configuration(location=location,
names=anames,
mount=mounts,
xyz=antxyz,
frame='global',
diameter=35.0)
return fc
def create_configuration_from_file(antfile: str, name: str = None, location: EarthLocation = None,
mount: str = 'altaz',
names: str = "%d", frame: str = 'local',
diameter = 35.0,
meta: dict = None,
**kwargs):
""" Define from a file
:param names:
:param antfile: Antenna file name
:param name: Name of array e.g. 'LOWBD2'
:param location:
:param mount: mount type: 'altaz', 'xy'
:param frame: 'local' | 'global'
:param diameter: Effective diameter of station or antenna
:param meta: Any meta info
:returns: Configuration
"""
antxyz = numpy.genfromtxt(antfile, delimiter=",")
assert antxyz.shape[1] == 3, ("Antenna array has wrong shape %s" % antxyz.shape)
nants = antxyz.shape[0]
if frame == 'local':
latitude = location.geodetic[1].to(u.rad).value
antxyz = xyz_at_latitude(antxyz, latitude)
anames = [names % ant for ant in range(nants)]
mounts = numpy.repeat(mount, nants)
fc = Configuration(location=location, names=anames, mount=mounts, xyz=antxyz, frame=frame,
diameter=diameter)
return fc
def create_configuration_from_file(antfile: str,
name: str = None,
location: EarthLocation = None,
mount: str = 'altaz',
names: str = "%d",
frame: str = 'local',
diameter=35.0,
meta: dict = None,
rmax=None,
**kwargs) -> Configuration:
""" Define from a file
:param names:
:param antfile: Antenna file name
:param name: Name of array e.g. 'LOWBD2'
:param location:
:param mount: mount type: 'altaz', 'xy'
:param frame: 'local' | 'global'
:param diameter: Effective diameter of station or antenna
:param meta: Any meta info
:return: Configuration
"""
antxyz = numpy.genfromtxt(antfile, delimiter=",")
assert antxyz.shape[1] == 3, ("Antenna array has wrong shape %s" %
antxyz.shape)
if frame == 'local':
latitude = location.geodetic[1].to(u.rad).value
antxyz = xyz_at_latitude(antxyz, latitude)
if rmax is not None:
lantxyz = antxyz - numpy.average(antxyz, axis=0)
r = numpy.sqrt(lantxyz[:, 0]**2 + lantxyz[:, 1]**2 + lantxyz[:, 2]**2)
antxyz = antxyz[r < rmax]
log.debug(
'create_configuration_from_file: Maximum radius %.1f m includes %d antennas/stations'
% (rmax, antxyz.shape[0]))
nants = antxyz.shape[0]
anames = [names % ant for ant in range(nants)]
mounts = numpy.repeat(mount, nants)
fc = Configuration(location=location,
names=anames,
mount=mounts,
xyz=antxyz,
frame=frame,
diameter=diameter)
return fc
def create_named_configuration(name: str = 'LOWBD2', **kwargs):
""" Standard configurations e.g. LOWBD2, MIDBD2
:param name: name of Configuration LOWBD2, LOWBD1, LOFAR, VLAA
:returns: Configuration
"""
if name == 'LOWBD2':
location = EarthLocation(lon="116.4999", lat="-26.7000", height=300.0)
fc = create_configuration_from_file(antfile=arl_path("data/configurations/LOWBD2.csv"),
location=location, mount='xy', names='LOWBD2_%d',
diameter=35.0)
elif name == 'LOWBD1':
location = EarthLocation(lon="116.4999", lat="-26.7000", height=300.0)
fc = create_configuration_from_file(antfile=arl_path("data/configurations/LOWBD1.csv"),
location=location, mount='xy', names='LOWBD1_%d',
diameter=35.0)
elif name == 'LOWBD2-CORE':
location = EarthLocation(lon="116.4999", lat="-26.7000", height=300.0)
fc = create_configuration_from_file(antfile=arl_path("data/configurations/LOWBD2-CORE.csv"),
location=location, mount='xy', names='LOWBD2_%d',
diameter=35.0)
elif name == 'LOFAR':
fc = create_LOFAR_configuration(antfile=arl_path("data/configurations/LOFAR.csv"),
diameter=35.0)
elif name == 'VLAA':
location = EarthLocation(lon="-107.6184", lat="34.0784", height=2124.0)
fc = create_configuration_from_file(antfile=arl_path("data/configurations/VLA_A_hor_xyz.csv"),
location=location,
mount='altaz',
names='VLA_%d',
diameter=25.0)
elif name == 'VLAA_north':
location = EarthLocation(lon="-107.6184", lat="90.000", height=2124.0)
fc = create_configuration_from_file(antfile=arl_path("data/configurations/VLA_A_hor_xyz.csv"),
location=location,
mount='altaz',
names='VLA_%d',
diameter=25.0)
else:
fc = Configuration()
raise ValueError("No such Configuration %s" % name)
return fc
def create_visibility_from_ms(msname, channum=0):
""" Minimal MS to Visibility converter
The MS format is much more general than the ARL Visibility so we cut many corners. This requires casacore to be
installed. If not an exception ModuleNotFoundError is raised.
Creates a list of Visibilities, one per phasecentre
"""
try:
from casacore.tables import table # pylint: disable=import-error
except ModuleNotFoundError:
raise ModuleNotFoundError("casacore is not installed")
tab = table(msname)
print(tab.info())
fields = numpy.unique(tab.getcol('FIELD_ID'))
print("Found unique field ids %s" % fields)
vis_list = list()
for field in fields:
# First get the main table information
ms = tab.query("FIELD_ID==%d" % field)
print("Found %d rows for field %d" % (ms.nrows(), field))
time = ms.getcol('TIME')
channels = len(numpy.transpose(ms.getcol('DATA'))[0])
print("Found %d channels" % (channels))
try:
vis = ms.getcol('DATA')[:, channum, :]
except IndexError:
raise IndexError("channel number exceeds max. within ms")
weight = ms.getcol('WEIGHT')
uvw = -1 * ms.getcol('UVW')
antenna1 = ms.getcol('ANTENNA1')
antenna2 = ms.getcol('ANTENNA2')
integration_time = ms.getcol('INTERVAL')
ddid = ms.getcol('DATA_DESC_ID')
# Now get info from the subtables
spwtab = table('%s/SPECTRAL_WINDOW' % msname, ack=False)
cfrequency = spwtab.getcol('CHAN_FREQ')
frequency = numpy.array([cfrequency[dd] for dd in ddid])[:, channum]
cchannel_bandwidth = spwtab.getcol('CHAN_WIDTH')
channel_bandwidth = numpy.array(
[cchannel_bandwidth[dd] for dd in ddid])[:, 0]
uvw *= frequency[:, numpy.newaxis] / constants.c.to('m/s').value
# Get polarisation info
# poltab = table('%s/POLARIZATION' % msname, ack=False)
# corr_type = poltab.getcol('CORR_TYPE')
# TODO: Do interpretation correctly
polarisation_frame = PolarisationFrame('stokesIQUV')
# Get configuration
anttab = table('%s/ANTENNA' % msname, ack=False)
mount = anttab.getcol('MOUNT')
names = anttab.getcol('NAME')
diameter = anttab.getcol('DISH_DIAMETER')
xyz = anttab.getcol('POSITION')
configuration = Configuration(name='',
data=None,
location=None,
names=names,
xyz=xyz,
mount=mount,
frame=None,
receptor_frame=ReceptorFrame("linear"),
diameter=diameter)
# Get phasecentres
fieldtab = table('%s/FIELD' % msname, ack=False)
pc = fieldtab.getcol('PHASE_DIR')[field, 0, :]
phasecentre = SkyCoord(ra=[pc[0]] * u.rad,
dec=pc[1] * u.rad,
frame='icrs',
equinox='J2000')
vis_list.append(
Visibility(uvw=uvw,
time=time,
antenna1=antenna1,
antenna2=antenna2,
frequency=frequency,
vis=vis,
weight=weight,
imaging_weight=weight,
integration_time=integration_time,
channel_bandwidth=channel_bandwidth,
configuration=configuration,
phasecentre=phasecentre,
polarisation_frame=polarisation_frame))
return vis_list