Masking out the solar disk¶
How to mask out all emission from the solar disk.
import matplotlib.pyplot as plt import numpy as np import numpy.ma as ma import sunpy.map from sunpy.data.sample import AIA_171_IMAGE from sunpy.map.maputils import all_coordinates_from_map
We start with the sample data
aia = sunpy.map.Map(AIA_171_IMAGE)
A utility function gives us access to the helioprojective coordinate of each pixels. We can use that to create a new array which contains the normalized radial position for each pixel.
With this information, we create a mask where all values which are less then the solar radius are masked. We also make a slight change to the colormap so that masked values are shown as black instead of the default white.
/home/docs/checkouts/readthedocs.org/user_builds/sunpy/checkouts/stable/examples/computer_vision_techniques/mask_disk.py:33: MatplotlibDeprecationWarning: You are modifying the state of a globally registered colormap. In future versions, you will not be able to modify a registered colormap in-place. To remove this warning, you can make a copy of the colormap first. cmap = copy.copy(mpl.cm.get_cmap("SDO AIA 171.0 Angstrom")) palette.set_bad('black')
Finally we create a new map with our new mask.
Let’s plot the results using our modified colormap
Total running time of the script: ( 0 minutes 0.969 seconds)