Merge pull request sunpy#7220 from TrestanSimon/add-gong-map-class

Add gong map class

changelog/7220.feature.rst

@@ -0,0 +1 @@
+Added a GONG synoptic map class which fixes non-compliant FITS metadata

sunpy/data/test/gong_synoptic.header

@@ -0,0 +1,78 @@
+SIMPLE  =                    T / Written by IDL:  Sat Sep 30 07:44:13 2023
+BITPIX  =                  -32 / Bits per pixel
+NAXIS   =                    2 / Number of axes
+NAXIS1  =                  360 / Axis length
+NAXIS2  =                  180 / Axis length
+EXTEND  =                    F / File may contain extensions
+ORIGIN  = 'National Solar Observatory -- GONG' / FITS file originator
+OBS-SITE= 'NSO/GONG NETWORK'   / Instrument site location
+TELESCOP= 'NSO-GONG'           / NSO/GONG Network
+OBS-URL = 'http://gong.nso.edu' / The GONG website
+DATE    = '2023-09-30T06:44:00'
+DATE-OBS= '2023-09-30'
+TIME-OBS= '06:44   '
+DATATYPE= 'REAL*4  '           / Type of data
+WAVELNTH=                676.8 / Wavelength of obs (nm)
+CAM_TYPE= 'SMD     '           / Camera manufacture type
+SN_CAMS = '1014 1016 1027 1029 1017' / Camera serial numbers
+CAR_ROT =                 2276 / Carr-rot. number of position 0.0
+WCSNAME = 'Carrington Cylin-equal-area'
+CTYPE1  = 'CRLN-CEA'           / Carrington longitude
+CTYPE2  = 'CRLT-CEA'           / Carrington sine latitude
+CRPIX1  =              180.500 / 180 degrees from initial longitude
+CRPIX2  =              90.5000 / Equator of map
+CRVAL1  =                  130 / Carrington longitude of map cntr (deg)
+CRVAL2  =              0.00000 / Sine-lat of Equator
+PV2_1   =              1.00000 / Lambda for latitude coordinate
+CDELT1  =              1.00000 / Carrington long. step (deg)
+CDELT2  =            0.0111111 / Sine-lat step
+WCSNAMEA= 'Carrington-rotation Cylin-equal-area'
+CTYPE1A = 'CRN-CEA '           / Carrington rotation number
+CTYPE2A = 'CRLT-CEA'           / Carrington sine latitude
+CRPIX1A =              180.500 / Half rotation from initial pixel
+CRPIX2A =              90.5000 / Equator of map
+CRVAL1A =          2275.638889 / Carr-rot of map cntr
+CRVAL2A =              0.00000 / Sine-lat of Equator
+PV2_1A  =              1.00000 / Lambda for latitude coordinate
+CDELT1A =    -0.00277777777778 / Carrington step (rotation)
+CDELT2A =            0.0111111 / Sine-lat step
+IMTYPE  = 'MAGNETIC'
+NFILETOT=                 4281 / Total number of files included
+LONG0   =                  310 / Init. Carr-long. of synoptic map
+IMGMN01 =            -0.082834 / Image mean
+IMGRMS01=            23.409344 / Image RMS (Standard Deviation)
+IMGSKW01=             4.185349 / Image skewness
+IMGMIN01=          -509.079071 / Image Min
+IMGMAX01=           846.215271 / Image Max
+IMGADV01=             7.367440 / Image Average Deviation
+IMGVAR01=           547.997375 / Image Variance
+IMGKUR01=           189.706238 / Image Kurtosis
+MMREL   = 'v2.3    '
+CARROT  =                 2276
+BUNIT   = 'Gauss   '
+LONGMC  =                 72.0
+LONGIMC =                   72
+LONGADJ =           -0.3273368
+MAPCOUNT=                 4281
+MAPL0   =                   10
+MAPEDGE =                  310
+CREDGE  =          2276.138889 / Carr-rot of map left edge
+CRNOW   =         2275.9731315 / Carr-rot of Now
+CR60    =         2275.9722222 / Carr-rot of 60 degrees in
+CRCENTER=         2275.6388889 / Carr-rot of map cntr
+MAPNAME = '2276_310'
+MAPDATE = '2023-09-30'         / UT Date of this map (i.e. of last contributor)
+MAPTIME = '06:44   '           / UT Time of this map (i.e. of last contributor)
+FILELIST= 'mrbql230930t0644c2276_310'
+COMMENT
+COMMENT Please note:
+COMMENT This is an hourly GONG product with UT date MAPDATE and UT time MAPTIME
+COMMENT which is between 59.5 and 60.5 degrees from the left edge in the
+COMMENT Carrington frame.
+COMMENT
+COMMENT This GONG product is produced from the QRII data stream.
+COMMENT
+COMMENT See http://gong.nso.edu for more information about GONG.
+COMMENT
+PLATFORM= 'Linux ncs-gong-proc1-lx redhat NOAO/IRAF V2.13-BETA'
+FITSWASH= '$RCSfile: mag_hourly.kw,v $ $Revision: 2.4 $ $Date: 2021/11/05 23:35'

sunpy/map/sources/__init__.py

@@ -7,6 +7,7 @@
 """
 
 from sunpy.map.map_factory import Map
+from .gong import *
 from .hinode import *
 from .iris import *
 from .mlso import *

sunpy/map/sources/gong.py

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+"""
+GONG Map subclass definitions
+"""
+import numpy as np
+
+import astropy.units as u
+from astropy.time import Time
+
+from sunpy.coordinates import get_earth
+from sunpy.map import GenericMap
+
+__all__ = ['GONGSynopticMap']
+
+from sunpy.map.mapbase import SpatialPair
+
+
+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 242×256 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>`_
+    """
+
+    @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):
+        return Time(f"{self.meta.get('date-obs')} {self.meta.get('time-obs')}")
+
+    @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)

sunpy/map/sources/tests/test_gong_synoptic_source.py

@@ -0,0 +1,52 @@
+import pytest
+
+import astropy.units as u
+
+from sunpy.data.test import get_dummy_map_from_header, get_test_filepath
+from sunpy.map.sources.gong import GONGSynopticMap
+
+
+@pytest.fixture
+def gong_synoptic():
+    return get_dummy_map_from_header(get_test_filepath('gong_synoptic.header'))
+
+
+def test_fitstoGONGSynoptic(gong_synoptic):
+    """Tests the creation of GongSynopticMap using FITS."""
+    assert isinstance(gong_synoptic, GONGSynopticMap)
+
+
+def test_is_datasource_for(gong_synoptic):
+    """Test the is_datasource_for method of GongSynopticMap."""
+    assert gong_synoptic.is_datasource_for(gong_synoptic.data, gong_synoptic.meta)
+
+
+def test_observatory(gong_synoptic):
+    """Tests the observatory property of the GongSynopticMap object."""
+    assert gong_synoptic.observatory == "NSO-GONG"
+
+
+def test_measurement(gong_synoptic):
+    """Tests the measurement property of the GongSynopticMap object."""
+    assert gong_synoptic.measurement == 676.8
+
+
+def test_date(gong_synoptic):
+    """Check that accessing the date doesn't raise a warning."""
+    gong_synoptic.date
+
+
+def test_unit(gong_synoptic):
+    assert gong_synoptic.unit == u.G
+    assert gong_synoptic.unit == u.Unit("Mx/cm^2")
+    assert gong_synoptic.unit.to_string() == 'G'
+
+
+def test_spatial_units(gong_synoptic):
+    assert gong_synoptic.spatial_units[0] == u.deg
+    assert gong_synoptic.spatial_units[1] == u.deg
+
+
+def test_wcs(gong_synoptic):
+    # Smoke test that WCS is valid and can transform from pixels to world coordinates
+    gong_synoptic.pixel_to_world(0*u.pix, 0*u.pix)