def from_header(cls, header, hdu_bands=None, format=None):
"""Create a WCS geometry object from a FITS header.
Parameters
----------
header : `~astropy.io.fits.Header`
The FITS header
hdu_bands : `~astropy.io.fits.BinTableHDU`
The BANDS table HDU.
format : {'gadf', 'fgst-ccube','fgst-template'}
FITS format convention.
Returns
-------
wcs : `~WcsGeom`
WCS geometry object.
"""
wcs = WCS(header, naxis=2)
# TODO: see https://github.com/astropy/astropy/issues/9259
wcs._naxis = wcs._naxis[:2]
axes = MapAxes.from_table_hdu(hdu_bands, format=format)
shape = axes.shape
if hdu_bands is not None and "NPIX" in hdu_bands.columns.names:
npix = hdu_bands.data.field("NPIX").reshape(shape + (2, ))
npix = (npix[..., 0], npix[..., 1])
cdelt = hdu_bands.data.field("CDELT").reshape(shape + (2, ))
cdelt = (cdelt[..., 0], cdelt[..., 1])
elif "WCSSHAPE" in header:
wcs_shape = eval(header["WCSSHAPE"])
npix = (wcs_shape[0], wcs_shape[1])
cdelt = None
wcs.array_shape = npix
else:
npix = (header["NAXIS1"], header["NAXIS2"])
cdelt = None
if "PSLICE1" in header:
cutout_info = {}
cutout_info["parent-slices"] = (
str_to_slice(header["PSLICE2"]),
str_to_slice(header["PSLICE1"]),
)
cutout_info["cutout-slices"] = (
str_to_slice(header["CSLICE2"]),
str_to_slice(header["CSLICE1"]),
)
else:
cutout_info = None
return cls(wcs, npix, cdelt=cdelt, axes=axes, cutout_info=cutout_info)
def from_header(cls, header, hdu_bands=None):
"""Create a WCS geometry object from a FITS header.
Parameters
----------
header : `~astropy.io.fits.Header`
The FITS header
hdu_bands : `~astropy.io.fits.BinTableHDU`
The BANDS table HDU.
Returns
-------
wcs : `~WcsGeom`
WCS geometry object.
"""
wcs = WCS(header, naxis=2)
# TODO: see https://github.com/astropy/astropy/issues/9259
wcs._naxis = wcs._naxis[:2]
axes = find_and_read_bands(hdu_bands)
shape = tuple([ax.nbin for ax in axes])
if hdu_bands is not None and "NPIX" in hdu_bands.columns.names:
npix = hdu_bands.data.field("NPIX").reshape(shape + (2, ))
npix = (npix[..., 0], npix[..., 1])
cdelt = hdu_bands.data.field("CDELT").reshape(shape + (2, ))
cdelt = (cdelt[..., 0], cdelt[..., 1])
elif "WCSSHAPE" in header:
wcs_shape = eval(header["WCSSHAPE"])
npix = (wcs_shape[0], wcs_shape[1])
cdelt = None
else:
npix = (header["NAXIS1"], header["NAXIS2"])
cdelt = None
if "PSLICE1" in header:
cutout_info = {}
cutout_info["parent-slices"] = (
str_to_slice(header["PSLICE2"]),
str_to_slice(header["PSLICE1"]),
)
cutout_info["cutout-slices"] = (
str_to_slice(header["CSLICE2"]),
str_to_slice(header["CSLICE1"]),
)
else:
cutout_info = None
return cls(wcs, npix, cdelt=cdelt, axes=axes, cutout_info=cutout_info)
