Re-projecting from CAR to CEA

The pfsspy solver takes a cylindrical-equal-area (CEA) projected magnetic field map as input, which is equally spaced in sin(latitude). Some synoptic field maps are equally spaced in latitude, a plate carée (CAR) projection, and need reprojecting.

This example shows how to use the pfsspy.utils.car_to_cea function to reproject a CAR projection to a CEA projection that pfsspy can take as input.

import matplotlib.pyplot as plt

from pfsspy import sample_data, utils

Load a sample ADAPT map, which has a CAR projection

adapt_maps = utils.load_adapt(sample_data.get_adapt_map())
adapt_map_car = adapt_maps[0]

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Re-project into a CEA projection

adapt_map_cea = utils.car_to_cea(adapt_map_car)

INFO: Missing metadata for solar radius: assuming the standard radius of the photosphere. [sunpy.map.mapbase]
/home/docs/checkouts/readthedocs.org/user_builds/pfsspy/envs/stable/lib/python3.10/site-packages/sunpy/map/mapbase.py:628: SunpyMetadataWarning: Missing metadata for observer: assuming Earth-based observer.
For frame 'heliographic_stonyhurst' the following metadata is missing: hglt_obs,hgln_obs,dsun_obs
For frame 'heliographic_carrington' the following metadata is missing: crln_obs,dsun_obs,crlt_obs

  obs_coord = self.observer_coordinate

Plot the original map and the reprojected map

plt.figure()
adapt_map_car.plot()
plt.figure()
adapt_map_cea.plot()

plt.show()

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