def _verify_global_info(global_info):
"""
Given the global time reference frame information, verify that
each global time coordinate attribute will be given a valid value.
Parameters
----------
global_info : dict
Global time reference frame information.
"""
# Translate FITS deprecated scale into astropy scale, or else just convert
# to lower case for further checks.
global_info['scale'] = FITS_DEPRECATED_SCALES.get(
global_info['TIMESYS'], global_info['TIMESYS'].lower())
# Verify global time scale
if global_info['scale'] not in Time.SCALES:
# 'GPS' and 'LOCAL' are FITS recognized time scale values
# but are not supported by astropy.
if global_info['scale'] == 'gps':
warnings.warn(
'Global time scale (TIMESYS) has a FITS recognized time scale '
'value "GPS". In Astropy, "GPS" is a time from epoch format '
'which runs synchronously with TAI; GPS is approximately 19 s '
'ahead of TAI. Hence, this format will be used.',
AstropyUserWarning)
# Assume that the values are in GPS format
global_info['scale'] = 'tai'
global_info['format'] = 'gps'
if global_info['scale'] == 'local':
warnings.warn(
'Global time scale (TIMESYS) has a FITS recognized time scale '
'value "LOCAL". However, the standard states that "LOCAL" should be '
'tied to one of the existing scales because it is intrinsically '
'unreliable and/or ill-defined. Astropy will thus use the default '
'global time scale "UTC" instead of "LOCAL".',
AstropyUserWarning)
# Default scale 'UTC'
global_info['scale'] = 'utc'
global_info['format'] = None
else:
raise AssertionError(
'Global time scale (TIMESYS) should have a FITS recognized '
'time scale value (got {!r}). The FITS standard states that '
'the use of local time scales should be restricted to alternate '
'coordinates.'.format(global_info['TIMESYS']))
else:
# Scale is already set
global_info['format'] = None
# Check if geocentric global location is specified
obs_geo = [
global_info[attr] for attr in ('OBSGEO-X', 'OBSGEO-Y', 'OBSGEO-Z')
if attr in global_info
]
# Location full specification is (X, Y, Z)
if len(obs_geo) == 3:
global_info['location'] = EarthLocation.from_geocentric(*obs_geo,
unit=u.m)
else:
# Check if geodetic global location is specified (since geocentric failed)
# First warn the user if geocentric location is partially specified
if obs_geo:
warnings.warn(
'The geocentric observatory location {} is not completely '
'specified (X, Y, Z) and will be ignored.'.format(obs_geo),
AstropyUserWarning)
# Check geodetic location
obs_geo = [
global_info[attr] for attr in ('OBSGEO-L', 'OBSGEO-B', 'OBSGEO-H')
if attr in global_info
]
if len(obs_geo) == 3:
global_info['location'] = EarthLocation.from_geodetic(*obs_geo)
else:
# Since both geocentric and geodetic locations are not specified,
# location will be None.
# Warn the user if geodetic location is partially specified
if obs_geo:
warnings.warn(
'The geodetic observatory location {} is not completely '
'specified (lon, lat, alt) and will be ignored.'.format(
obs_geo), AstropyUserWarning)
global_info['location'] = None
# Get global time reference
# Keywords are listed in order of precedence, as stated by the standard
for key, format_ in (('MJDREF', 'mjd'), ('JDREF', 'jd'), ('DATEREF',
'fits')):
if key in global_info:
global_info['ref_time'] = {
'val': global_info[key],
'format': format_
}
break
else:
# If none of the three keywords is present, MJDREF = 0.0 must be assumed
global_info['ref_time'] = {'val': 0, 'format': 'mjd'}
def _verify_global_info(global_info):
"""
Given the global time reference frame information, verify that
each global time coordinate attribute will be given a valid value.
Parameters
----------
global_info : dict
Global time reference frame information.
"""
# Translate FITS deprecated scale into astropy scale, or else just convert
# to lower case for further checks.
global_info['scale'] = FITS_DEPRECATED_SCALES.get(global_info['TIMESYS'],
global_info['TIMESYS'].lower())
# Verify global time scale
if global_info['scale'] not in Time.SCALES:
# 'GPS' and 'LOCAL' are FITS recognized time scale values
# but are not supported by astropy.
if global_info['scale'] == 'gps':
warnings.warn(
'Global time scale (TIMESYS) has a FITS recognized time scale '
'value "GPS". In Astropy, "GPS" is a time from epoch format '
'which runs synchronously with TAI; GPS is approximately 19 s '
'ahead of TAI. Hence, this format will be used.', AstropyUserWarning)
# Assume that the values are in GPS format
global_info['scale'] = 'tai'
global_info['format'] = 'gps'
if global_info['scale'] == 'local':
warnings.warn(
'Global time scale (TIMESYS) has a FITS recognized time scale '
'value "LOCAL". However, the standard states that "LOCAL" should be '
'tied to one of the existing scales because it is intrinsically '
'unreliable and/or ill-defined. Astropy will thus use the default '
'global time scale "UTC" instead of "LOCAL".', AstropyUserWarning)
# Default scale 'UTC'
global_info['scale'] = 'utc'
global_info['format'] = None
else:
raise AssertionError(
'Global time scale (TIMESYS) should have a FITS recognized '
'time scale value (got {!r}). The FITS standard states that '
'the use of local time scales should be restricted to alternate '
'coordinates.'.format(global_info['TIMESYS']))
else:
# Scale is already set
global_info['format'] = None
# Check if geocentric global location is specified
obs_geo = [global_info[attr] for attr in ('OBSGEO-X', 'OBSGEO-Y', 'OBSGEO-Z')
if attr in global_info]
# Location full specification is (X, Y, Z)
if len(obs_geo) == 3:
global_info['location'] = EarthLocation.from_geocentric(*obs_geo, unit=u.m)
else:
# Check if geodetic global location is specified (since geocentric failed)
# First warn the user if geocentric location is partially specified
if obs_geo:
warnings.warn(
'The geocentric observatory location {} is not completely '
'specified (X, Y, Z) and will be ignored.'.format(obs_geo),
AstropyUserWarning)
# Check geodetic location
obs_geo = [global_info[attr] for attr in ('OBSGEO-L', 'OBSGEO-B', 'OBSGEO-H')
if attr in global_info]
if len(obs_geo) == 3:
global_info['location'] = EarthLocation.from_geodetic(*obs_geo)
else:
# Since both geocentric and geodetic locations are not specified,
# location will be None.
# Warn the user if geodetic location is partially specified
if obs_geo:
warnings.warn(
'The geodetic observatory location {} is not completely '
'specified (lon, lat, alt) and will be ignored.'.format(obs_geo),
AstropyUserWarning)
global_info['location'] = None
# Get global time reference
# Keywords are listed in order of precedence, as stated by the standard
for key, format_ in (('MJDREF', 'mjd'), ('JDREF', 'jd'), ('DATEREF', 'fits')):
if key in global_info:
global_info['ref_time'] = {'val': global_info[key], 'format': format_}
break
else:
# If none of the three keywords is present, MJDREF = 0.0 must be assumed
global_info['ref_time'] = {'val': 0, 'format': 'mjd'}
def _verify_column_info(column_info, global_info):
"""
Given the column-specific time reference frame information, verify that
each column-specific time coordinate attribute has a valid value.
Return True if the coordinate column is time, or else return False.
Parameters
----------
global_info : dict
Global time reference frame information.
column_info : dict
Column-specific time reference frame override information.
"""
scale = column_info.get('TCTYP', None)
unit = column_info.get('TCUNI', None)
location = column_info.get('TRPOS', None)
if scale is not None:
# Non-linear coordinate types have "4-3" form and are not time coordinates
if TCTYP_RE_TYPE.match(scale[:5]) and TCTYP_RE_ALGO.match(scale[5:]):
return False
elif scale.lower() in Time.SCALES:
column_info['scale'] = scale.lower()
column_info['format'] = None
elif scale in FITS_DEPRECATED_SCALES.keys():
column_info['scale'] = FITS_DEPRECATED_SCALES[scale]
column_info['format'] = None
# TCTYPn (scale) = 'TIME' indicates that the column scale is
# controlled by the global scale.
elif scale == 'TIME':
column_info['scale'] = global_info['scale']
column_info['format'] = global_info['format']
elif scale == 'GPS':
warnings.warn(
'Table column "{}" has a FITS recognized time scale value "GPS". '
'In Astropy, "GPS" is a time from epoch format which runs '
'synchronously with TAI; GPS runs ahead of TAI approximately '
'by 19 s. Hence, this format will be used.'.format(
column_info), AstropyUserWarning)
column_info['scale'] = 'tai'
column_info['format'] = 'gps'
elif scale == 'LOCAL':
warnings.warn(
'Table column "{}" has a FITS recognized time scale value "LOCAL". '
'However, the standard states that "LOCAL" should be tied to one '
'of the existing scales because it is intrinsically unreliable '
'and/or ill-defined. Astropy will thus use the global time scale '
'(TIMESYS) as the default.'.format(column_info),
AstropyUserWarning)
column_info['scale'] = global_info['scale']
column_info['format'] = global_info['format']
else:
# Coordinate type is either an unrecognized local time scale
# or a linear coordinate type
return False
# If TCUNIn is a time unit or TRPOSn is specified, the column is a time
# coordinate. This has to be tested since TCTYP (scale) is not specified.
elif (unit is not None and unit in FITS_TIME_UNIT) or location is not None:
column_info['scale'] = global_info['scale']
column_info['format'] = global_info['format']
# None of the conditions for time coordinate columns is satisfied
else:
return False
# Check if column-specific reference position TRPOSn is specified
if location is not None:
# Observatory position (location) needs to be specified only
# for 'TOPOCENTER'.
if location == 'TOPOCENTER':
column_info['location'] = global_info['location']
if column_info['location'] is None:
warnings.warn(
'Time column reference position "TRPOSn" value is "TOPOCENTER". '
'However, the observatory position is not properly specified. '
'The FITS standard does not support this and hence reference '
'position will be ignored.', AstropyUserWarning)
else:
column_info['location'] = None
# Warn user about ignoring global reference position when TRPOSn is
# not specified
elif global_info['TREFPOS'] == 'TOPOCENTER':
if global_info['location'] is not None:
warnings.warn(
'Time column reference position "TRPOSn" is not specified. The '
'default value for it is "TOPOCENTER", and the observatory position '
'has been specified. However, for supporting column-specific location, '
'reference position will be ignored for this column.',
AstropyUserWarning)
column_info['location'] = None
else:
column_info['location'] = None
# Get reference time
column_info['ref_time'] = global_info['ref_time']
return True
def _verify_column_info(column_info, global_info):
"""
Given the column-specific time reference frame information, verify that
each column-specific time coordinate attribute has a valid value.
Return True if the coordinate column is time, or else return False.
Parameters
----------
global_info : dict
Global time reference frame information.
column_info : dict
Column-specific time reference frame override information.
"""
scale = column_info.get('TCTYP', None)
unit = column_info.get('TCUNI', None)
location = column_info.get('TRPOS', None)
if scale is not None:
# Non-linear coordinate types have "4-3" form and are not time coordinates
if TCTYP_RE_TYPE.match(scale[:5]) and TCTYP_RE_ALGO.match(scale[5:]):
return False
elif scale.lower() in Time.SCALES:
column_info['scale'] = scale.lower()
column_info['format'] = None
elif scale in FITS_DEPRECATED_SCALES.keys():
column_info['scale'] = FITS_DEPRECATED_SCALES[scale]
column_info['format'] = None
# TCTYPn (scale) = 'TIME' indicates that the column scale is
# controlled by the global scale.
elif scale == 'TIME':
column_info['scale'] = global_info['scale']
column_info['format'] = global_info['format']
elif scale == 'GPS':
warnings.warn(
'Table column "{}" has a FITS recognized time scale value "GPS". '
'In Astropy, "GPS" is a time from epoch format which runs '
'synchronously with TAI; GPS runs ahead of TAI approximately '
'by 19 s. Hence, this format will be used.'.format(column_info),
AstropyUserWarning)
column_info['scale'] = 'tai'
column_info['format'] = 'gps'
elif scale == 'LOCAL':
warnings.warn(
'Table column "{}" has a FITS recognized time scale value "LOCAL". '
'However, the standard states that "LOCAL" should be tied to one '
'of the existing scales because it is intrinsically unreliable '
'and/or ill-defined. Astropy will thus use the global time scale '
'(TIMESYS) as the default.'. format(column_info),
AstropyUserWarning)
column_info['scale'] = global_info['scale']
column_info['format'] = global_info['format']
else:
# Coordinate type is either an unrecognized local time scale
# or a linear coordinate type
return False
# If TCUNIn is a time unit or TRPOSn is specified, the column is a time
# coordinate. This has to be tested since TCTYP (scale) is not specified.
elif (unit is not None and unit in FITS_TIME_UNIT) or location is not None:
column_info['scale'] = global_info['scale']
column_info['format'] = global_info['format']
# None of the conditions for time coordinate columns is satisfied
else:
return False
# Check if column-specific reference position TRPOSn is specified
if location is not None:
# Observatory position (location) needs to be specified only
# for 'TOPOCENTER'.
if location == 'TOPOCENTER':
column_info['location'] = global_info['location']
if column_info['location'] is None:
warnings.warn(
'Time column reference position "TRPOSn" value is "TOPOCENTER". '
'However, the observatory position is not properly specified. '
'The FITS standard does not support this and hence reference '
'position will be ignored.', AstropyUserWarning)
else:
column_info['location'] = None
# Since TRPOSn is not specified, global reference position is
# considered.
elif global_info['TREFPOS'] == 'TOPOCENTER':
column_info['location'] = global_info['location']
if column_info['location'] is None:
warnings.warn(
'Time column reference position "TRPOSn" is not specified. The '
'default value for it is "TOPOCENTER", but due to unspecified '
'observatory position, reference position will be ignored.',
AstropyUserWarning)
else:
column_info['location'] = None
# Get reference time
column_info['ref_time'] = global_info['ref_time']
return True