def test_precision(self):
"""Set the output precision which is used for some formats. This is
also a test of the code that provides a dict for global and instance
options."""
t = Time("2010-01-01 00:00:00", format="iso", scale="utc")
# Uses initial class-defined precision=3
assert t.iso == "2010-01-01 00:00:00.000"
# Set global precision = 5 XXX this uses private var, FIX THIS
Time._precision = 5
assert t.iso == "2010-01-01 00:00:00.00000"
# Set instance precision to 9
t.precision = 9
assert t.iso == "2010-01-01 00:00:00.000000000"
assert t.tai.utc.iso == "2010-01-01 00:00:00.000000000"
# Restore global to original default of 3, instance is still at 9
Time._precision = 3
assert t.iso == "2010-01-01 00:00:00.000000000"
# Make a new time instance and confirm precision = 3
t = Time("2010-01-01 00:00:00", format="iso", scale="utc")
assert t.iso == "2010-01-01 00:00:00.000"
def _parse_hdus(cls, hdulist):
header = MetaDict(OrderedDict(hdulist[0].header))
# these GBM files have three FITS extensions.
# extn1 - this gives the energy range for each of the 128 energy bins
# extn2 - this contains the data, e.g. counts, exposure time, time of observation
# extn3 - eclipse times?
energy_bins = hdulist[1].data
count_data = hdulist[2].data
misc = hdulist[3].data
# rebin the 128 energy channels into some summary ranges
# 4-15 keV, 15 - 25 keV, 25-50 keV, 50-100 keV, 100-300 keV, 300-800 keV, 800 - 2000 keV
# put the data in the units of counts/s/keV
summary_counts = _bin_data_for_summary(energy_bins, count_data)
# get the time information in datetime format with the correct MET adjustment
gbm_times = Time([fermi.met_to_utc(t) for t in count_data['time']])
gbm_times.precision = 9
gbm_times = gbm_times.isot.astype('datetime64')
column_labels = ['4-15 keV', '15-25 keV', '25-50 keV', '50-100 keV',
'100-300 keV', '300-800 keV', '800-2000 keV']
# Add the units data
units = OrderedDict([('4-15 keV', u.ct / u.s / u.keV), ('15-25 keV', u.ct / u.s / u.keV),
('25-50 keV', u.ct / u.s / u.keV), ('50-100 keV', u.ct / u.s / u.keV),
('100-300 keV', u.ct / u.s / u.keV), ('300-800 keV', u.ct / u.s / u.keV),
('800-2000 keV', u.ct / u.s / u.keV)])
return pd.DataFrame(summary_counts, columns=column_labels, index=gbm_times), header, units
def _get_time():
t = Time([[1], [2]], format='cxcsec',
location=EarthLocation(1000, 2000, 3000, unit=u.km))
t.format = 'iso'
t.precision = 5
t.delta_ut1_utc = np.array([[3.0], [4.0]])
t.delta_tdb_tt = np.array([[5.0], [6.0]])
t.out_subfmt = 'date_hm'
return t
def wcs_casa2astropy(coordsys):
"""
Convert a casac.coordsys object into an astropy.wcs.WCS object
"""
# Rather than try and parse the CASA coordsys ourselves, we delegate
# to CASA by getting it to write out a FITS file and reading back in
# using WCS
header = fits.Header()
# Observer information (ObsInfo.cc)
header['OBSERVER'] = coordsys['observer']
header['TELESCOP'] = coordsys['telescope']
if coordsys['obsdate']['refer'] == 'LAST':
header['TIMESYS'] = 'UTC'
else:
header['TIMESYS'] = coordsys['obsdate']['refer']
header['MJD-OBS'] = coordsys['obsdate']['m0']['value']
dateobs = Time(header['MJD-OBS'],
format='mjd',
scale=coordsys['obsdate']['refer'].lower())
dateobs.precision = 6
header['DATE-OBS'] = dateobs.isot
if 'telescopeposition' in coordsys:
obsgeo_lon = coordsys['telescopeposition']['m0']['value']
obsgeo_lat = coordsys['telescopeposition']['m1']['value']
obsgeo_alt = coordsys['telescopeposition']['m2']['value']
header['OBSGEO-X'] = obsgeo_alt * np.cos(obsgeo_lon) * np.cos(
obsgeo_lat)
header['OBSGEO-Y'] = obsgeo_alt * np.sin(obsgeo_lon) * np.cos(
obsgeo_lat)
header['OBSGEO-Z'] = obsgeo_alt * np.sin(obsgeo_lat)
# World coordinates
# Find worldmap entries
worldmap = {}
for key, value in coordsys.items():
if key.startswith('worldmap'):
index = int(key[8:])
worldmap[index] = value
# Now iterate through the different coordinate types to populate the WCS
header['WCSAXES'] = np.max([np.max(idx) + 1 for idx in worldmap.values()])
# Initialize PC
for ii in range(header['WCSAXES']):
for jj in range(header['WCSAXES']):
header[f'PC{ii+1}_{jj+1}'] = 0.
for coord_type in ('direction', 'spectral', 'stokes', 'linear'):
# Each coordinate type is stored with a numerical index,
# so for example a cube might have direction0 and
# spectral1, or spectral0, direction1, stokes2. The actual
# index is irrelevant for the rest of the loop.
for index in range(len(worldmap)):
if f'{coord_type}{index}' in coordsys:
data = coordsys[f'{coord_type}{index}']
break
else:
# Skip the rest of the loop for the current coord_type
# since the coord_type wasn't found with any index.
continue
if coord_type == 'direction':
idx1, idx2 = worldmap[index] + 1
header[f'CTYPE{idx1}'] = AXES_TO_CTYPE[data['system']][
data['axes'][0]] + '-' + data['projection']
header[f'CTYPE{idx2}'] = AXES_TO_CTYPE[data['system']][
data['axes'][1]] + '-' + data['projection']
header[f'CRPIX{idx1}'] = data['crpix'][0] + 1
header[f'CRPIX{idx2}'] = data['crpix'][1] + 1
header[f'CRVAL{idx1}'] = data['crval'][0]
header[f'CRVAL{idx2}'] = data['crval'][1]
header[f'CDELT{idx1}'] = data['cdelt'][0]
header[f'CDELT{idx2}'] = data['cdelt'][1]
header[f'CUNIT{idx1}'] = sanitize_unit(data['units'][0])
header[f'CUNIT{idx2}'] = sanitize_unit(data['units'][1])
header['LONPOLE'] = data['longpole']
header['LATPOLE'] = data['latpole']
if data.get('system') in EQUATORIAL_SYSTEMS:
header['RADESYS'] = RADESYS[data['conversionSystem']]
if data['conversionSystem'] in EQUINOX:
header['EQUINOX'] = EQUINOX[data['conversionSystem']]
# NOTE: unclear if it is deliberate that the following is always
# ?_2 and ?_1 or whether it should depend on the index of the
# longitude.
if data.get('system') in EQUATORIAL_SYSTEMS:
header[f'PV{idx2}_1'] = 0.
header[f'PV{idx2}_2'] = 0.
header[f'PC{idx1}_{idx1}'] = data['pc'][0, 0]
header[f'PC{idx1}_{idx2}'] = data['pc'][0, 1]
header[f'PC{idx2}_{idx1}'] = data['pc'][1, 0]
header[f'PC{idx2}_{idx2}'] = data['pc'][1, 1]
elif coord_type == 'stokes':
idx = worldmap[index][0] + 1
header[f'CTYPE{idx}'] = 'STOKES'
header[f'CRVAL{idx}'] = data['crval'][0]
header[f'CRPIX{idx}'] = data['crpix'][0] + 1
header[f'CDELT{idx}'] = data['cdelt'][0]
header[f'CUNIT{idx}'] = ''
header[f'PC{idx}_{idx}'] = data['pc'][0][0]
elif coord_type == 'spectral':
idx = worldmap[index][0] + 1
if 'tabular' in data:
header[f'CTYPE{idx}'] = AXES_TO_CTYPE[data['tabular']['axes']
[0]]
header[f'CRVAL{idx}'] = data['tabular']['crval'][0]
header[f'CRPIX{idx}'] = data['tabular']['crpix'][0] + 1
# It looks like we can't just use:
# header[f'CDELT{idx}'] = data['tabular']['cdelt'][0]
# because this doesn't match what appears in a FITS header
# exported from CASA. Instead we use the interval between the
# first two tabulated values. See
# https://github.com/radio-astro-tools/spectral-cube/issues/614
# for more information.
header[f'CDELT{idx}'] = np.diff(
data['tabular']['worldvalues'][:2])[0]
header[f'CUNIT{idx}'] = data['tabular']['units'][0]
else:
header[f'CTYPE{idx}'] = data['wcs']['ctype']
header[f'CRVAL{idx}'] = data['wcs']['crval']
header[f'CRPIX{idx}'] = data['wcs']['crpix'] + 1
header[f'CDELT{idx}'] = data['wcs']['cdelt']
header[f'CUNIT{idx}'] = data['unit']
header[f'PC{idx}_{idx}'] = 1.0
header[f'RESTFRQ'] = data['restfreq']
if data['system'] in SPECSYS:
header[f'SPECSYS'] = SPECSYS[data['system']]
elif coord_type == 'linear':
indices = worldmap[index] + 1
for idx1 in range(len(indices)):
header[f'CTYPE{indices[idx1]}'] = data['axes'][idx1].upper()
header[f'CRVAL{indices[idx1]}'] = data['crval'][idx1]
header[f'CRPIX{indices[idx1]}'] = data['crpix'][idx1] + 1
header[f'CDELT{indices[idx1]}'] = data['cdelt'][idx1]
header[f'CUNIT{indices[idx1]}'] = data['units'][idx1]
for idx2 in range(len(indices)):
header[f'PC{indices[idx1]}_{indices[idx1]}'] = data['pc'][
idx1, idx1]
header[f'PC{indices[idx1]}_{indices[idx2]}'] = data['pc'][
idx1, idx2]
header[f'PC{indices[idx2]}_{indices[idx1]}'] = data['pc'][
idx2, idx1]
header[f'PC{indices[idx2]}_{indices[idx2]}'] = data['pc'][
idx2, idx2]
else:
raise NotImplementedError(f'coord_type is {coord_type}')
return WCS(header)
