Source code for photutils.datasets.load

# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""
This module provides tools for loading example datasets, from both
within photutils and remote servers.
"""

from urllib.error import HTTPError, URLError

from astropy.io import fits
from astropy.table import Table
from astropy.utils.data import download_file, get_pkg_data_filename

__all__ = ['get_path', 'load_spitzer_image', 'load_spitzer_catalog',
           'load_irac_psf', 'load_fermi_image', 'load_star_image',
           'load_simulated_hst_star_image']


[docs]def get_path(filename, location='local', cache=True, show_progress=False): """ Get path (location on your disk) for a given file. Parameters ---------- filename : str File name in the local or remote data folder. location : {'local', 'remote', 'photutils-datasets'} File location. ``'local'`` means bundled with ``photutils``. ``'remote'`` means the astropy data server (or the photutils-datasets repo as a backup) or the Astropy cache on your machine. ``'photutils-datasets'`` means the photutils-datasets repo or the Astropy cache on your machine. cache : bool, optional Whether to cache the contents of remote URLs. Default is `True`. show_progress : bool, optional Whether to display a progress bar during the download (default is `False`). Returns ------- path : str Path (location on your disk) of the file. Examples -------- >>> from astropy.io import fits >>> from photutils.datasets import get_path >>> hdulist = fits.open(get_path('fermi_counts.fits.gz')) """ datasets_url = ('https://github.com/astropy/photutils-datasets/raw/' f'main/data/{filename}') if location == 'local': path = get_pkg_data_filename('data/' + filename) elif location == 'remote': # pragma: no cover try: url = f'https://data.astropy.org/photometry/{filename}' path = download_file(url, cache=cache, show_progress=show_progress) except (URLError, HTTPError): # timeout or not found path = download_file(datasets_url, cache=cache, show_progress=show_progress) elif location == 'photutils-datasets': # pragma: no cover path = download_file(datasets_url, cache=cache, show_progress=show_progress) else: raise ValueError(f'Invalid location: {location}') return path
[docs]def load_spitzer_image(show_progress=False): # pragma: no cover """ Load a 4.5 micron Spitzer image. The catalog for this image is returned by :func:`load_spitzer_catalog`. Parameters ---------- show_progress : bool, optional Whether to display a progress bar during the download (default is `False`). Returns ------- hdu : `~astropy.io.fits.ImageHDU` The 4.5 micron Spitzer image in a FITS image HDU. See Also -------- load_spitzer_catalog Examples -------- .. plot:: :include-source: from photutils.datasets import load_spitzer_image hdu = load_spitzer_image() plt.imshow(hdu.data, origin='lower', vmax=50) """ path = get_path('spitzer_example_image.fits', location='remote', show_progress=show_progress) hdu = fits.open(path)[0] return hdu
[docs]def load_spitzer_catalog(show_progress=False): # pragma: no cover """ Load a 4.5 micron Spitzer catalog. The image from which this catalog was derived is returned by :func:`load_spitzer_image`. Parameters ---------- show_progress : bool, optional Whether to display a progress bar during the download (default is `False`). Returns ------- catalog : `~astropy.table.Table` The catalog of sources. See Also -------- load_spitzer_image Examples -------- .. plot:: :include-source: from photutils.datasets import load_spitzer_catalog catalog = load_spitzer_catalog() plt.scatter(catalog['l'], catalog['b']) plt.xlabel('Galactic l') plt.ylabel('Galactic b') plt.xlim(18.39, 18.05) plt.ylim(0.13, 0.30) """ path = get_path('spitzer_example_catalog.xml', location='remote', show_progress=show_progress) table = Table.read(path) return table
[docs]def load_irac_psf(channel, show_progress=False): # pragma: no cover """ Load a Spitzer IRAC PSF image. Parameters ---------- channel : int (1-4) The IRAC channel number: * Channel 1: 3.6 microns * Channel 2: 4.5 microns * Channel 3: 5.8 microns * Channel 4: 8.0 microns show_progress : bool, optional Whether to display a progress bar during the download (default is `False`). Returns ------- hdu : `~astropy.io.fits.ImageHDU` The IRAC PSF in a FITS image HDU. Examples -------- .. plot:: :include-source: from astropy.visualization import LogStretch, ImageNormalize from photutils.datasets import load_irac_psf hdu1 = load_irac_psf(1) hdu2 = load_irac_psf(2) hdu3 = load_irac_psf(3) hdu4 = load_irac_psf(4) norm = ImageNormalize(hdu1.data, stretch=LogStretch()) fig, ((ax1, ax2), (ax3, ax4)) = plt.subplots(2, 2) ax1.imshow(hdu1.data, origin='lower', interpolation='nearest', norm=norm) ax1.set_title('IRAC Ch1 PSF') ax2.imshow(hdu2.data, origin='lower', interpolation='nearest', norm=norm) ax2.set_title('IRAC Ch2 PSF') ax3.imshow(hdu3.data, origin='lower', interpolation='nearest', norm=norm) ax3.set_title('IRAC Ch3 PSF') ax4.imshow(hdu4.data, origin='lower', interpolation='nearest', norm=norm) ax4.set_title('IRAC Ch4 PSF') plt.tight_layout() plt.show() """ channel = int(channel) if channel < 1 or channel > 4: raise ValueError('channel must be 1, 2, 3, or 4') filepath = f'irac_ch{channel}_flight.fits' path = get_path(filepath, location='remote', show_progress=show_progress) hdu = fits.open(path)[0] return hdu
[docs]def load_fermi_image(show_progress=False): """ Load a Fermi counts image for the Galactic center region. Parameters ---------- show_progress : bool, optional Whether to display a progress bar during the download (default is `False`). Returns ------- hdu : `~astropy.io.fits.ImageHDU` A FITS image HDU. Examples -------- .. plot:: :include-source: from photutils.datasets import load_fermi_image hdu = load_fermi_image() plt.imshow(hdu.data, vmax=10, origin='lower', interpolation='nearest') """ path = get_path('fermi_counts.fits.gz', location='local', show_progress=show_progress) hdu = fits.open(path)[1] return hdu
[docs]def load_star_image(show_progress=False): # pragma: no cover """ Load an optical image of stars. This is an image of M67 from photographic data obtained as part of the National Geographic Society - Palomar Observatory Sky Survey (NGS-POSS). The image was digitized from the POSS-I Red plates as part of the Digitized Sky Survey produced at the Space Telescope Science Institute. Parameters ---------- show_progress : bool, optional Whether to display a progress bar during the download (default is `False`). Returns ------- hdu : `~astropy.io.fits.ImageHDU` The M67 image in a FITS image HDU. Examples -------- .. plot:: :include-source: from photutils.datasets import load_star_image hdu = load_star_image() plt.imshow(hdu.data, origin='lower', interpolation='nearest') """ path = get_path('M6707HH.fits', location='remote', show_progress=show_progress) hdu = fits.open(path)[0] return hdu
[docs]def load_simulated_hst_star_image(show_progress=False): # pragma: no cover """ Load a simulated HST WFC3/IR F160W image of stars. The simulated image does not contain any background or noise. Parameters ---------- show_progress : bool, optional Whether to display a progress bar during the download (default is `False`). Returns ------- hdu : `~astropy.io.fits.ImageHDU` A FITS image HDU containing the simulated HST star image. Examples -------- .. plot:: :include-source: from photutils.datasets import load_simulated_hst_star_image hdu = load_simulated_hst_star_image() plt.imshow(hdu.data, origin='lower', interpolation='nearest') """ path = get_path('hst_wfc3ir_f160w_simulated_starfield.fits', location='photutils-datasets', show_progress=show_progress) hdu = fits.open(path)[0] return hdu