diff options
Diffstat (limited to 'fg21sim/utils')
| -rw-r--r-- | fg21sim/utils/__init__.py | 2 | ||||
| -rw-r--r-- | fg21sim/utils/fits.py | 29 |
2 files changed, 30 insertions, 1 deletions
diff --git a/fg21sim/utils/__init__.py b/fg21sim/utils/__init__.py index b6cf3fd..97243a7 100644 --- a/fg21sim/utils/__init__.py +++ b/fg21sim/utils/__init__.py @@ -1,6 +1,6 @@ # Copyright (c) 2016 Weitian LI <liweitianux@live.com> # MIT license -from .fits import write_fits_healpix +from .fits import read_fits_healpix, write_fits_healpix from .healpix import healpix2hpx, hpx2healpix from .logging import setup_logging diff --git a/fg21sim/utils/fits.py b/fg21sim/utils/fits.py index e865528..be5dc68 100644 --- a/fg21sim/utils/fits.py +++ b/fg21sim/utils/fits.py @@ -9,6 +9,7 @@ from datetime import datetime, timezone import numpy as np from astropy.io import fits +import healpy as hp # Reference: @@ -26,6 +27,34 @@ FITS_COLUMN_FORMATS = { } +def read_fits_healpix(filename): + """Read the HEALPix map from a FITS file to 1D array in *RING* ordering. + + Parameters + ---------- + filename : str + Filename of the HEALPix FITS file + + Returns + ------- + data : 1D `~numpy.ndarray` + HEALPix data in *RING* ordering + header : `~astropy.io.fits.Header` + Header of the input FITS file + + NOTE + ---- + This function wraps on `healpy.read_map()`, but set the data type of + data array to its original value as in FITS file, as well as return + FITS header as `~astropy.io.fits.Header` instance. + """ + hdu = fits.open(filename)[0] + dtype = hdu.data.dtype + header = hdu.header + data = hp.read_map(hdu, nest=False, verbose=False) + return (data.astype(dtype), header) + + def write_fits_healpix(filename, hpmap, header=None, clobber=False): """Write the HEALPix map to a FITS file with proper header as well as the user-provided header. |