"""
==============================================
Auto-Aligning AIA and HMI Data During Plotting
==============================================

This example shows how a map is autoaligned when it is plotted on a different
reference frame.

See :ref:`sphx_glr_generated_gallery_map_transformations_reprojection_align_aia_hmi.py`
for an alternate approach to image alignment, where one of the maps is modified
prior to plotting, and thus is available for purposes other than plotting.
"""
# sphinx_gallery_tags = ["Map", "AIA", "HMI"]

import matplotlib.pyplot as plt

import astropy.units as u

import sunpy.data.sample
import sunpy.map

######################################################################
# We use the AIA image and HMI image from the sample data. For the
# HMI map, we use the special HMI color map, which expects the plotted
# range to be -1500 to 1500.

map_aia = sunpy.map.Map(sunpy.data.sample.AIA_171_IMAGE)
map_hmi = sunpy.map.Map(sunpy.data.sample.HMI_LOS_IMAGE)
map_hmi.plot_settings['cmap'] = "hmimag"
map_hmi.plot_settings['norm'] = plt.Normalize(-1500, 1500)

######################################################################
# Plot both images side by side. Note by the tick labels that the HMI
# image is oriented "upside down" relative to the AIA image.

fig = plt.figure(figsize=(12, 5))
ax1 = fig.add_subplot(121, projection=map_aia)
map_aia.plot(axes=ax1, clip_interval=(1, 99.9)*u.percent)
ax2 = fig.add_subplot(122, projection=map_hmi)
map_hmi.plot(axes=ax2)

######################################################################
# Now let us intentionally set the ``projection`` for the right panel
# to be ``map_aia`` instead of ``map_hmi``. This time, plotting the
# HMI image onto axes defined by the AIA reference frame will trigger
# "autoalignment" functionality where each map pixel is individually
# drawn. The HMI image now has the same orientation as the AIA image.
#
# Note that off-disk HMI data are not retained by default because an
# additional assumption is required to define the location of the HMI
# emission in 3D space. We can use `~sunpy.coordinates.SphericalScreen`
# to retain the off-disk HMI data. See
# :ref:`sphx_glr_generated_gallery_map_transformations_reprojection_spherical_screen.py`
# for more reference.

fig = plt.figure(figsize=(12, 5))
ax1 = fig.add_subplot(121, projection=map_aia)
map_aia.plot(axes=ax1, clip_interval=(1, 99.9)*u.percent)
ax2 = fig.add_subplot(122, projection=map_aia)
map_hmi.plot(axes=ax2, title='HMI image in AIA reference frame')

######################################################################
# We can directly plot them over one another, by setting the
# transparency of the HMI plot.

fig = plt.figure()
ax1 = fig.add_subplot(projection=map_aia)
map_aia.plot(axes=ax1, clip_interval=(1, 99.9)*u.percent)
map_hmi.plot(axes=ax1, alpha=0.5)
ax1.set_title('HMI overlaid on AIA')

plt.show()

# sphinx_gallery_thumbnail_number = 2