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"""
============================
Drawing a rectangle on a map
============================
This example will demonstrate how to draw a rectangle 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
import sunpy.data.sample
import sunpy.map
################################################################################
# Let's start with a sample AIA image.
aia_map = sunpy.map.Map(sunpy.data.sample.AIA_171_IMAGE)
################################################################################
# Here are four different ways to draw a rectangle. The first three ways
# directly calls the `~astropy.coordinates.SkyCoord` class. The fourth way
# converts pixel coordinates to the equivalent `~astropy.coordinates.SkyCoord`
# objects using the :meth:`~sunpy.map.GenericMap.pixel_to_world`.
# sphinx_gallery_defer_figures
fig = plt.figure(figsize=(5, 5))
ax = fig.add_subplot(projection=aia_map)
aia_map.plot(axes=ax, clip_interval=(1, 99.99)*u.percent)
################################################################################
# Specify two opposite corners of the rectangle as a single, two-element
# SkyCoord object.
# sphinx_gallery_defer_figures
coords = SkyCoord(
Tx=(100, 500) * u.arcsec,
Ty=(200, 500) * u.arcsec,
frame=aia_map.coordinate_frame,
)
aia_map.draw_quadrangle(
coords,
axes=ax,
edgecolor="blue",
linestyle="-",
linewidth=2,
label='2-element SkyCoord'
)
################################################################################
# Specify two opposite corners of the rectangle as separate SkyCoord objects.
# sphinx_gallery_defer_figures
bottom_left = SkyCoord(-500 * u.arcsec, 200 * u.arcsec, frame=aia_map.coordinate_frame)
top_right = SkyCoord(-100 * u.arcsec, 500 * u.arcsec, frame=aia_map.coordinate_frame)
aia_map.draw_quadrangle(
bottom_left,
axes=ax,
top_right=top_right,
edgecolor="green",
linestyle="--",
linewidth=2,
label='two SkyCoords'
)
################################################################################
# Specify one corner of the rectangle and the rectangle's width and height.
# sphinx_gallery_defer_figures
bottom_left = SkyCoord(-500 * u.arcsec, -500 * u.arcsec, frame=aia_map.coordinate_frame)
width = 400 * u.arcsec
height = 300 * u.arcsec
aia_map.draw_quadrangle(
bottom_left,
axes=ax,
width=width,
height=height,
edgecolor="yellow",
linestyle="-.",
linewidth=2,
label='width/height'
)
################################################################################
# Draw a desired rectangle in pixel coordinates by first converting to SkyCoord objects.
bottom_left = aia_map.pixel_to_world(600 * u.pixel, 350 * u.pixel)
top_right = aia_map.pixel_to_world(800 * u.pixel, 450 * u.pixel)
aia_map.draw_quadrangle(
bottom_left,
axes=ax,
top_right=top_right,
edgecolor="red",
linestyle=":",
linewidth=2,
label='pixel_to_world()'
)
ax.legend()
plt.show()
|
