"""SOHO Map subclass definitions"""
import numpy as np
import astropy.units as u
from astropy.coordinates import CartesianRepresentation, HeliocentricMeanEcliptic
from astropy.visualization import PowerStretch
from astropy.visualization.mpl_normalize import ImageNormalize
from sunpy import log
from sunpy.map.mapbase import GenericMap, SpatialPair
from sunpy.map.sources.source_type import source_stretch
from sunpy.time import parse_time
__all__ = ['EITMap', 'LASCOMap', 'MDIMap', 'MDISynopticMap']
[docs]
class EITMap(GenericMap):
"""
SOHO EIT Image Map.
SOHO EIT is an extreme ultraviolet (EUV) imager able to image the solar
transition region and inner corona in four selected bandpasses,
171 (Fe IX/X), 195 (Fe XII), 284 (Fe XV), and 304 (He II) Angstrom.
SOHO was launched on 2 December 2 1995 into a sun-synchronous orbit and
primary mission operations for SOHO EIT ended at the end of July 2010.
References
----------
* `SOHO Mission Page <https://sohowww.nascom.nasa.gov/>`_
* `SOHO EIT Instrument Page <https://umbra.nascom.nasa.gov/eit/>`_
* `SOHO EIT User Guide <https://umbra.nascom.nasa.gov/eit/eit_guide/>`_
"""
def __init__(self, data, header, **kwargs):
super().__init__(data, header, **kwargs)
self._nickname = self.detector
self.plot_settings['cmap'] = self._get_cmap_name()
self.plot_settings['norm'] = ImageNormalize(
stretch=source_stretch(self.meta, PowerStretch(0.5)), clip=False)
@property
def date(self):
# Old EIT data has date-obs in format of dd-JAN-yy so we use date_obs where available
return self._get_date('date_obs') or super().date
@property
def spatial_units(self):
"""
If not present in CUNIT{1,2} keywords, defaults to arcsec.
"""
return SpatialPair(u.Unit(self.meta.get('cunit1', 'arcsec')),
u.Unit(self.meta.get('cunit2', 'arcsec')))
@property
def waveunit(self):
"""
If WAVEUNIT FITS keyword isn't present, defaults to Angstrom.
"""
unit = self.meta.get("waveunit", "Angstrom") or "Angstrom"
return u.Unit(unit)
@property
def detector(self):
return "EIT"
@property
def rsun_obs(self):
return u.Quantity(self.meta['solar_r'] * self.meta['cdelt1'], 'arcsec')
@property
def _supported_observer_coordinates(self):
return [(('hec_x', 'hec_y', 'hec_z'), {'x': self.meta.get('hec_x'),
'y': self.meta.get('hec_y'),
'z': self.meta.get('hec_z'),
'unit': u.km,
'representation_type': CartesianRepresentation,
'frame': HeliocentricMeanEcliptic})
] + super()._supported_observer_coordinates
[docs]
@classmethod
def is_datasource_for(cls, data, header, **kwargs):
"""Determines if header corresponds to an EIT image"""
return header.get('instrume') == 'EIT'
[docs]
class LASCOMap(GenericMap):
"""
SOHO LASCO Image Map
The Large Angle and Spectrometric COronagraph (LASCO) is a set of three
Lyot-type coronagraphs (C1, C2, and C3) that image the solar corona from
1.1 to 32 solar radii.
The C1 images rom 1.1 to 3 solar radii. The C2 telescope images the corona
from 2 to 6 solar radii, overlapping the outer field-of-view of C1 from 2 to
3 solar radii. The C3 telescope extends the field-of-view to 32 solar radii.
SOHO was launched on 2 December 2 1995 into a sun-synchronous orbit.
References
----------
* `SOHO Mission Page <https://sohowww.nascom.nasa.gov/>`_
"""
def __init__(self, data, header, **kwargs):
super().__init__(data, header, **kwargs)
self.plot_settings['cmap'] = f'soholasco{self.detector[1]!s}'
self.plot_settings['norm'] = ImageNormalize(
stretch=source_stretch(self.meta, PowerStretch(0.5)), clip=False)
@property
def spatial_units(self):
return SpatialPair(u.Unit(self.meta.get('cunit1').lower()),
u.Unit(self.meta.get('cunit2').lower()))
@property
def rotation_matrix(self):
# For Helioviewer images, clear rotation metadata, as these have already been rotated.
# Also check that all CROTAn keywords exist to make sure that it's an untouched
# Helioviewer file.
if ('helioviewer' in self.meta and
'crota' in self.meta and
'crota1' in self.meta and
'crota2' in self.meta):
log.debug("LASCOMap: Ignoring CROTAn keywords "
"because the map has already been rotated by Helioviewer")
return np.identity(2)
else:
return super().rotation_matrix
@property
def date(self):
if date := self.meta.get('date-obs', self.meta.get('date_obs')):
# If the header has already been fixed, no need to concatenate
if (time := self.meta.get('time-obs', self.meta.get('time_obs'))) and 'T' not in date:
date = f"{date}T{time}"
date = parse_time(date)
return date or super().date
def _set_date(self, date):
if 'time-obs' in self.meta:
time_key = 'time-obs'
del self.meta['time-obs']
if 'time_obs' in self.meta:
time_key = 'time_obs'
del self.meta['time_obs']
date_key = 'date-obs' if 'date-obs' in self.meta else 'date_obs'
if time_key in self.meta:
self.meta[date_key], self.meta[time_key] = parse_time(date).utc.isot.split('T')
else:
self.meta[date_key] = parse_time(date).utc.isot
@property
def nickname(self):
filter = self.meta.get('filter', '')
return f'{self.instrument}-{self.detector} {filter}'
@nickname.setter
def nickname(self, value):
raise AttributeError("Cannot manually set nickname for LASCOMap")
@property
def measurement(self):
# TODO: This needs to do more than white-light. Should give B, pB, etc.
return "white-light"
@property
def unit(self):
bunit = self.meta.get('bunit', None)
if bunit is not None and bunit == 0:
# The HV JP2 files given to us have a 0 value BUNIT
return u.dimensionless_unscaled
return super().unit
[docs]
@classmethod
def is_datasource_for(cls, data, header, **kwargs):
"""Determines if header corresponds to an LASCO image."""
return header.get('instrume') == 'LASCO'
[docs]
class MDIMap(GenericMap):
"""
SOHO MDI Image Map
The Michelson Doppler Imager (MDI) is a white light refracting telescope
which feeds sunlight through a series of filters onto a CCD camera. Two
tunable Michelson interformeters define a 94 mAngstrom bandpass that can be
tuned across the Ni 6768 Angstrom solar absorption line.
MDI measures line-of-sight motion (Dopplergrams), magnetic field
(magnetograms), and brightness images of the full solar disk at several
resolutions (4 arc-second to very low resolution) and a fixed selected
region in higher resolution (1.2 arc-second).
SOHO was launched on 2 December 2 1995 into a sun-synchronous orbit and
SOHO MDI ceased normal science observations on 12 April 2011.
References
----------
* `SOHO Mission Page <https://sohowww.nascom.nasa.gov/>`_
* `SOHO MDI Instrument Page <http://soi.stanford.edu>`_
* `SOHO MDI Fits Header keywords <http://soi.stanford.edu/sssc/doc/keywords.html>`_
* `SOHO MDI Instrument Paper <https://doi.org/10.1007/978-94-009-0191-9_5>`_
"""
def __init__(self, data, header, **kwargs):
super().__init__(data, header, **kwargs)
if self.unit is not None and self.unit.is_equivalent(u.T):
# Magnetic field maps, not intensity maps
self._set_symmetric_vmin_vmax()
@property
def _date_obs(self):
if 'T' in self.meta.get('date-obs', ''):
# Helioviewer MDI files have the full date in DATE_OBS, but we still
# want to let normal FITS files use DATE-OBS
return parse_time(self.meta['date-obs'])
elif 'date_obs' in self.meta:
return parse_time(self.meta['date_obs'])
@property
def unit(self):
bunit = self.meta.get('bunit', None)
if bunit is not None and bunit.lower() == 'arbitrary intensity units':
return u.dimensionless_unscaled
return super().unit
@property
def spatial_units(self):
"""
If not present in CUNIT{1,2} keywords, defaults to arcsec.
"""
return SpatialPair(u.Unit(self.meta.get('cunit1', 'arcsec')),
u.Unit(self.meta.get('cunit2', 'arcsec')))
@staticmethod
def _is_mdi_map(header):
return header.get('instrume') == 'MDI' or header.get('camera') == 'MDI'
@staticmethod
def _is_synoptic_map(header):
return 'Synoptic Chart' in header.get('CONTENT', '')
@property
def _supported_observer_coordinates(self):
return [(('obs_l0', 'obs_b0', 'obs_dist'), {'lon': self.meta.get('obs_l0'),
'lat': self.meta.get('obs_b0'),
'radius': self.meta.get('obs_dist'),
'unit': (u.deg, u.deg, u.AU),
'frame': "heliographic_carrington"}),
] + super()._supported_observer_coordinates
@property
def instrument(self):
return "MDI"
@property
def waveunit(self):
"""
Always assumed to be Angstrom.
"""
return "Angstrom"
@property
def measurement(self):
"""
Returns the measurement type.
"""
return self.meta.get('CONTENT', '')
[docs]
@classmethod
def is_datasource_for(cls, data, header, **kwargs):
"""Determines if header corresponds to an MDI image"""
return cls._is_mdi_map(header) and not cls._is_synoptic_map(header)
[docs]
class MDISynopticMap(MDIMap):
"""
SOHO MDI synoptic magnetogram Map.
See the docstring of `MDIMap` for information on the MDI instrument.
"""
@property
def date(self):
"""
Image observation time.
This is taken from the 'DATE-OBS' or 'T_OBS' keywords.
"""
return self._get_date('date-obs') or self._get_date('t_obs') or super().date
def _set_date(self, date):
self.meta['date-obs'] = self.meta['t_obs'] = parse_time(date).utc.isot
@property
def spatial_units(self):
cunit1 = self.meta['cunit1']
if cunit1 == 'Degree':
cunit1 = 'deg'
cunit2 = self.meta['cunit2']
if cunit2 == 'Sine Latitude':
cunit2 = 'deg'
return SpatialPair(u.Unit(cunit1), u.Unit(cunit2))
@property
def unit(self):
bunit = self.meta.get('bunit', None)
if bunit is None:
return
# Maxwells aren't in the IAU unit style manual and therefore not a valid FITS unit
# The mapbase unit property forces this validation, so we must override it to prevent it.
return u.Unit(bunit)
@property
def scale(self):
if self.meta['cunit2'] == 'Sine Latitude':
# Since, this map uses the cylindrical equal-area (CEA) projection,
# the spacing should be modified to 180/pi times the original value
# Reference: Section 5.5, Thompson 2006
return SpatialPair(np.abs(self.meta['cdelt1']) * self.spatial_units[0] / u.pixel,
180 / np.pi * self.meta['cdelt2'] * u.deg / u.pixel)
[docs]
@classmethod
def is_datasource_for(cls, data, header, **kwargs):
"""Determines if header corresponds to an MDI image"""
return cls._is_mdi_map(header) and cls._is_synoptic_map(header)
