Re-projecting from CAR to CEA

The sunkit_magex.pfss 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 sunkit_magex.pfss.utils.car_to_cea function to reproject a CAR projection to a CEA projection that sunkit_magex.pfss can take as input.

import matplotlib.pyplot as plt

from sunkit_magex import pfss

Load a sample ADAPT map, which has a CAR projection.

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

Re-project into a CEA projection.

adapt_map_cea = pfss.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/sunkit-magex/conda/latest/lib/python3.10/site-packages/sunpy/map/mapbase.py:633: SunpyMetadataWarning: Missing metadata for observer: assuming Earth-based observer.
For frame 'heliographic_stonyhurst' the following metadata is missing: hgln_obs,dsun_obs,hglt_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()

• 
•