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"""
====================================
Drawing a rotated rectangle on a map
====================================
This example will demonstrate how to draw a rectangle that is rotated relative
to the axes on a map using :meth:`~sunpy.map.GenericMap.draw_quadrangle`.
"""
import matplotlib.pyplot as plt
import astropy.units as u
from astropy.coordinates import SkyCoord, SkyOffsetFrame
import sunpy.data.sample
import sunpy.map
################################################################################
# Let's start with a sample image of AIA 171.
aia_map = sunpy.map.Map(sunpy.data.sample.AIA_171_IMAGE)
################################################################################
# Define the rotation angle and center coordinate of the rectangle,
# as well as the width and height in physical units.
rotation_angle = 30 * u.deg
center_coord = SkyCoord(-100 * u.arcsec, -300 * u.arcsec, frame=aia_map.coordinate_frame)
width = 1000 * u.arcsec
height = 300 * u.arcsec
################################################################################
# We define a custom coordinate frame for the rotated rectangle by providing
# the center in the AIA 171 coordinate frame and rotation angle to
# `~astropy.coordinates.SkyOffsetFrame`. We then define a 2-element
# `~astropy.coordinates.SkyCoord` in that custom coordinate frame for the
# bottom-left and top-right corners of the rectangle.
offset_frame = SkyOffsetFrame(origin=center_coord, rotation=rotation_angle)
rectangle = SkyCoord(lon=[-1/2, 1/2] * width, lat=[-1/2, 1/2] * height, frame=offset_frame)
################################################################################
# Finally, we will draw the rotated rectangle and its center.
fig = plt.figure()
ax = fig.add_subplot(projection=aia_map)
aia_map.plot(axes=ax, clip_interval=(1, 99.99) * u.percent)
ax.plot_coord(center_coord, "o", color="red")
aia_map.draw_quadrangle(
rectangle,
axes=ax,
edgecolor="red",
linestyle="--",
linewidth=2,
)
plt.show()
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