"""
GONG Map subclass definitions
"""
import numpy as np
from matplotlib.colors import SymLogNorm
import astropy.units as u
from astropy.coordinates import EarthLocation, SkyCoord
from sunpy.coordinates import get_earth
from sunpy.map import GenericMap
from sunpy.map.mapbase import SpatialPair
from sunpy.time import parse_time
__all__ = ['GONGSynopticMap', 'GONGHalphaMap', 'GONGMagnetogramMap']
_SITE_NAMES = {
'LE': 'Learmonth, (AUS)',
'UD': 'Udaipur, (IND)',
'TD': 'El Teide, (ESP)',
'CT': 'Cerro Tololo, (CHL)',
'BB': 'Big Bear, (USA)',
'ML': 'Mauna Loa, (USA)'
}
[docs]
class GONGSynopticMap(GenericMap):
"""
GONG Synoptic Map.
The Global Oscillation Network Group (GONG) operates a six-station network of velocity
imagers located around the Earth that observe the Sun nearly continuously. GONG
produces hourly photospheric magnetograms using the Ni I 676.8 nm spectral line with an
array of 242 x 256 pixels covering the solar disk. These magnetograms are used to derive
synoptic maps which show a full-surface picture of the solar magnetic field.
References
----------
* `GONG Page <https://gong.nso.edu/>`__
* `Magnetogram Synoptic Map Images Page <https://gong.nso.edu/data/magmap/>`__
* `FITS header keywords <https://gong.nso.edu/data/DMAC_documentation/General/fitsdesc.html>`__
* `Instrument Paper (pp. 203-208) <https://inis.iaea.org/collection/NCLCollectionStore/_Public/20/062/20062491.pdf>`__
* `GONG+ Documentation <https://gong.nso.edu/data/DMAC_documentation/PipelineMap/GlobalMap.html>`__
"""
[docs]
@classmethod
def is_datasource_for(cls, data, header, **kwargs):
return (str(header.get('TELESCOP', '')).endswith('GONG') and
str(header.get('CTYPE1', '')).startswith('CRLN'))
@property
def date(self):
# The FITS file has a date that is made from the date-obs and time-obs keywords
# Which is not what date-obs is supposed to be.
if date_obs := self.meta.get('date-obs'):
if time_obs := self.meta.get('time-obs'):
date_obs = f"{date_obs} {time_obs}"
date_obs = parse_time(date_obs)
return date_obs or super().date
def _set_date(self, date):
if 'time-obs' in self.meta:
self.meta['date-obs'], self.meta['time-obs'] = parse_time(date).utc.isot.split('T')
else:
self.meta['date-obs'] = parse_time(date).utc.isot
@property
def reference_date(self):
return self.date
def _set_reference_date(self, date):
self._set_date(date)
@property
def scale(self):
# 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(self.meta['cdelt1'] * self.spatial_units[0] / u.pixel,
self.meta['cdelt2'] * 180 / np.pi * self.spatial_units[0] / u.pixel)
@property
def spatial_units(self):
return SpatialPair(u.deg, u.deg)
@property
def observer_coordinate(self):
return get_earth(self.date)
[docs]
class GONGHalphaMap(GenericMap):
"""
GONG H-Alpha Map.
The Global Oscillation Network Group (GONG) operates a six-station network of H-alpha
imagers located around the Earth that observe the Sun nearly continuously.
References
----------
* `GONG H-Alpha Page <https://nso.edu/data/nisp-data/h-alpha/>`__
* `GONG H-Alpha Observation Details <https://nispdata.nso.edu/webProdDesc2/presenter.php?file=halpha_fulldisk_images_overview.html&echoExact=0&name=Overview%20:%20GONG%20H-alpha%20Full-disk%20Images>`__
* `GONG Header Keywords <https://gong.nso.edu/data/HEADER_KEY.html>`__
* `GONG H-alpha Full-disk Images. <https://doi.org/10.25668/as28-7p13>`__
"""
[docs]
@classmethod
def is_datasource_for(cls, data, header, **kwargs):
return (str(header.get('TELESCOP', '')).endswith('GONG') and
str(header.get('IMTYPE', '')).startswith('H-ALPHA'))
@property
def scale(self):
solar_r = self.meta['SOLAR-R'] * u.arcsec
return SpatialPair(solar_r / (self.meta['FNDLMBMI'] * u.pixel),
solar_r/ (self.meta['FNDLMBMA'] * u.pixel))
@property
def rsun_obs(self):
# Header contains a radius keyword which seems to have a higher priority but for GONG Ha is in pixels
return self.meta['SOLAR-R'] * u.arcsec
@property
def coordinate_system(self):
"""
Coordinate system used
Overrides the values in the header which are not understood by Astropy WCS
"""
return SpatialPair("HPLN-TAN", "HPLT-TAN")
@property
def nickname(self):
site = _SITE_NAMES.get(self.meta.get("sitename", ""), "UNKNOWN")
return f'{self.observatory}, {site}'
@property
def spatial_units(self):
return SpatialPair(u.deg, u.deg)
@property
def _earth_location(self):
"""Location of the observatory on Earth"""
return EarthLocation.from_geodetic(lat=self.meta['site-lat'] * u.deg, lon=self.meta['site-lon'] * u.deg)
@property
def observer_coordinate(self):
return SkyCoord(self._earth_location.get_itrs(self.date)).heliographic_stonyhurst
[docs]
class GONGMagnetogramMap(GenericMap):
"""
GONG Magnetogram Map.
The Global Oscillation Network Group (GONG) operates a six-station network of Doppler
imagers distributed around the Earth, that observe the Sun nearly continuously.
GONG produces hourly photospheric magnetograms using the Ni I 676.8 nm spectral line.
References
----------
* `GONG Page <https://gong.nso.edu/>`__
* `GONG Data Archive <https://gong2.nso.edu/archive/patch.pl?menutype=s>`__
* `FITS header keywords <https://gong.nso.edu/data/DMAC_documentation/General/fitsdesc.html>`__
* `Instrument Paper (pp. 203-208) <https://inis.iaea.org/collection/NCLCollectionStore/_Public/20/062/20062491.pdf>`__
* `GONG+ Documentation <https://gong.nso.edu/data/DMAC_documentation/PipelineMap/GlobalMap.html>`__
"""
def __init__(self, data, header, **kwargs):
super().__init__(data, header, **kwargs)
data_abs_max = np.nanmax(np.abs(self.data))
self.plot_settings['norm'] = SymLogNorm(50, vmin=-data_abs_max, vmax=data_abs_max)
[docs]
@classmethod
def is_datasource_for(cls, data, header, **kwargs):
return (str(header.get('TELESCOP', '')).endswith('GONG') and
str(header.get('IMTYPE', '')) == 'MAGNETIC') and (str(header.get('DTYPE', '')) == 'OBSERVE')
@property
def date(self):
# The FITS file has a date that is made from the date-obs and time-obs keywords
# Which is not what date-obs is supposed to be.
if date_obs := self.meta.get('date-obs'):
if time_obs := self.meta.get('time-obs'):
date_obs_str = f"{date_obs} {time_obs}"
# Time in header is GPS and there no GPS scale in astropy so parse as TAI and add offset
# https://gssc.esa.int/navipedia/index.php/Transformations_between_Time_Systems#GNSS_–_TAI
date_obs = (parse_time(date_obs_str, scale='tai') + 19 *u.s).utc
return date_obs or super().date
def _set_date(self, date):
date = parse_time(date).tai - 19*u.s
if 'time-obs' in self.meta:
self.meta['date-obs'], self.meta['time-obs'] = date.isot.split('T')
else:
self.meta['date-obs'] = date.isot
@property
def reference_date(self):
return self.date
def _set_reference_date(self, date):
self._set_date(date)
@property
def scale(self):
solar_r = (self.meta['SEMIDIAM'] * u.rad).to(u.arcsec)
return SpatialPair(solar_r / (self.meta['FNDLMBMI'] * u.pixel),
solar_r / (self.meta['FNDLMBMA'] * u.pixel))
@property
def coordinate_system(self):
"""
Coordinate system used.
Overrides the values in the header which are not understood by Astropy WCS.
"""
return SpatialPair("HPLN-TAN", "HPLT-TAN")
@property
def nickname(self):
"""
Nicknames for the different sites, e.g BB for Big Bear.
"""
site = _SITE_NAMES.get(self.meta.get("site", ""), "UNKNOWN")
return f'{self.observatory}, {site}'
@property
def spatial_units(self):
return SpatialPair(u.deg, u.deg)
@property
def _earth_location(self):
return EarthLocation.from_geodetic(lat=self.meta['lat'] * u.rad, lon=self.meta['lon'] * u.rad,
height=self.meta['elev'] * u.m)
@property
def observer_coordinate(self):
return SkyCoord(self._earth_location.get_itrs(self.date)).heliographic_stonyhurst
@property
def rsun_obs(self):
return (self.meta['semidiam']*u.rad).to(u.arcsec)
@property
def instrument(self):
return 'Magnetogram'
