| # -*- coding: utf-8 -*- | |
| """ | |
| ======================================= | |
| Read and plot an image from a FITS file | |
| ======================================= | |
| This example opens an image stored in a FITS file and displays it to the screen. | |
| This example uses `astropy.utils.data` to download the file, `astropy.io.fits` to open | |
| the file, and `matplotlib.pyplot` to display the image. | |
| ------------------- | |
| *By: Lia R. Corrales, Adrian Price-Whelan, Kelle Cruz* | |
| *License: BSD* | |
| ------------------- | |
| """ | |
| ############################################################################## | |
| # Set up matplotlib and use a nicer set of plot parameters | |
| import matplotlib.pyplot as plt | |
| from astropy.visualization import astropy_mpl_style | |
| plt.style.use(astropy_mpl_style) | |
| ############################################################################## | |
| # Download the example FITS files used by this example: | |
| from astropy.utils.data import get_pkg_data_filename | |
| from astropy.io import fits | |
| image_file = get_pkg_data_filename('tutorials/FITS-images/HorseHead.fits') | |
| ############################################################################## | |
| # Use `astropy.io.fits.info()` to display the structure of the file: | |
| fits.info(image_file) | |
| ############################################################################## | |
| # Generally the image information is located in the Primary HDU, also known | |
| # as extension 0. Here, we use `astropy.io.fits.getdata()` to read the image | |
| # data from this first extension using the keyword argument ``ext=0``: | |
| image_data = fits.getdata(image_file, ext=0) | |
| ############################################################################## | |
| # The data is now stored as a 2D numpy array. Print the dimensions using the | |
| # shape attribute: | |
| print(image_data.shape) | |
| ############################################################################## | |
| # Display the image data: | |
| plt.figure() | |
| plt.imshow(image_data, cmap='gray') | |
| plt.colorbar() | |