import `sunpy.coordinates` causes bug in generating synthetic raster images

Though sunpy is not a required package for euispice_coreg, I personally often use some handy functions in sunpy.coordinates, including the propagate_with_solar_surface() context manager. However, by importing sunpy.coordinates, it will change the output behaviors of WCS.pixel_to_world() if it is in helioprojective coordinates. For example:

with fits.open('../../src/SPICE/20221024/solo_L2_spice-n-ras_20221024T231535_V07_150995398-000.fits') as hdul:
    wcs_spice = WCS(hdul[0].header).dropaxis(2)
    x, y, t = np.meshgrid(np.arange(0,2),
                        np.arange(0, 2),
                        np.arange(0, 2))
    print(wcs_spice.pixel_to_world(x,y,t))

gives the following without sunpy.coordinates

[<Quantity [[[0.19955875, 0.19955875],
            [0.20066612, 0.20066612]],

           [[0.19953378, 0.19953378],
            [0.20064116, 0.20064116]]] deg>, <Quantity [[[-0.01288007, -0.01288007],
            [-0.01278912, -0.01278912]],

           [[-0.01257609, -0.01257609],
            [-0.01248514, -0.01248514]]] deg>, <Time object: scale='utc' format='mjd' value=[[[59877.10270249 59877.10271406]
  [59877.10200515 59877.10201672]]

 [[59877.10270249 59877.10271406]
  [59877.10200515 59877.10201672]]]>]

Note that the output is a list with a length of 3 (x,y,t). On the other hand, with sunpy.coordinates the output will be organized into SkyCoord objects, so the length of the output list becomes 2 (SkyCoord, t).

[<SkyCoord (Helioprojective: obstime=2022-10-25T00:51:59.753, rsun=695700.0 km, observer=<HeliographicStonyhurst Coordinate (obstime=2022-10-25T00:51:59.753, rsun=695700.0 km): (lon, lat, radius) in (deg, deg, m)
    (-50.59290147, 6.48623548, 5.92481369e+10)>): (Tx, Ty) in arcsec
    [[[(718.41148829, -46.3682358 ), (718.41148829, -46.3682358 )],
      [(722.39804299, -46.04082854), (722.39804299, -46.04082854)]],

     [[(718.32161058, -45.27392775), (718.32161058, -45.27392775)],
      [(722.30816532, -44.94652046), (722.30816532, -44.94652046)]]]>, <Time object: scale='utc' format='mjd' value=[[[59877.10270249 59877.10271406]
  [59877.10200515 59877.10201672]]

 [[59877.10270249 59877.10271406]
  [59877.10200515 59877.10201672]]]>]

This difference will cause bugs in indexing the helioprojective longitudes and latitudes in SPICEComposedMapBuilder._prepare_spectro_data() in line 234 of map_builder.py:

 longitude_spice, latitude_spice, utc_spice = w_xyt.pixel_to_world(x, y, t)

It would be helpful to notify the users either do not import sunpy.coordinates in the python file or jupyter notebook using the SPICEComposedMapBuilder or change the code accordingly.

adolliou / euispice_coreg

import `sunpy.coordinates` causes bug in generating synthetic raster images #3