def write_fits(self,
filename,
clobber=False,
length_unit=None,
sky_scale=None,
sky_center=None):
r""" Write the PPVCube to a FITS file.
Parameters
----------
filename : string
The name of the file to write to.
clobber : boolean, optional
Whether to overwrite a file with the same name that already
exists. Default False.
length_unit : string, optional
The units to convert the coordinates to in the file.
sky_scale : tuple, optional
Conversion between an angle unit and a length unit, if sky
coordinates are desired, e.g. (1.0, "arcsec/kpc")
sky_center : tuple, optional
The (RA, Dec) coordinate in degrees of the central pixel. Must
be specified with *sky_scale*.
Examples
--------
>>> cube.write_fits("my_cube.fits", clobber=False,
... sky_scale=(1.0,"arcsec/kpc"), sky_center=(30.,45.))
"""
vunit = fits_info[self.axis_type][0]
vtype = fits_info[self.axis_type][1]
v_center = 0.5 * (self.vbins[0] + self.vbins[-1]).in_units(vunit).value
if length_unit is None:
units = str(self.ds.get_smallest_appropriate_unit(self.width))
else:
units = length_unit
units = sanitize_fits_unit(units)
dx = self.width.in_units(units).v / self.nx
dy = self.width.in_units(units).v / self.ny
dv = self.dv.in_units(vunit).v
w = _astropy.pywcs.WCS(naxis=3)
w.wcs.crpix = [
0.5 * (self.nx + 1), 0.5 * (self.ny + 1), 0.5 * (self.nv + 1)
]
w.wcs.cdelt = [dx, dy, dv]
w.wcs.crval = [0.0, 0.0, v_center]
w.wcs.cunit = [units, units, vunit]
w.wcs.ctype = ["LINEAR", "LINEAR", vtype]
fib = FITSImageData(self.data.transpose(), fields=self.field, wcs=w)
fib.update_all_headers("bunit", re.sub('()', '', str(self.proj_units)))
fib.update_all_headers("btype", self.field)
if sky_scale is not None and sky_center is not None:
fib.create_sky_wcs(sky_center, sky_scale)
fib.writeto(filename, clobber=clobber)
def to_fits_data(self,
fields=None,
other_keys=None,
length_unit=None,
**kwargs):
r"""Export the fields in this FixedResolutionBuffer instance
to a FITSImageData instance.
This will export a set of FITS images of either the fields specified
or all the fields already in the object.
Parameters
----------
fields : list of strings
These fields will be pixelized and output. If "None", the keys of
the FRB will be used.
other_keys : dictionary, optional
A set of header keys and values to write into the FITS header.
length_unit : string, optional
the length units that the coordinates are written in. The default
is to use the default length unit of the dataset.
"""
from yt.visualization.fits_image import FITSImageData
if length_unit is None:
length_unit = self.ds.length_unit
if "units" in kwargs:
issue_deprecation_warning("The 'units' keyword argument has been "
"replaced by the 'length_unit' keyword "
"argument and the former has been "
"deprecated. Setting 'length_unit' "
"to 'units'.")
length_unit = kwargs.pop("units")
if fields is None:
fields = list(self.data.keys())
else:
fields = ensure_list(fields)
if len(fields) == 0:
raise RuntimeError(
"No fields to export. Either pass a field or list of fields to "
"to_fits_data or access a field from the FixedResolutionBuffer "
"object.")
fid = FITSImageData(self, fields=fields, length_unit=length_unit)
if other_keys is not None:
for k, v in other_keys.items():
fid.update_all_headers(k, v)
return fid
def export_fits(self,
filename,
fields=None,
overwrite=False,
other_keys=None,
units="cm",
**kwargs):
r"""Export a set of pixelized fields to a FITS file.
This will export a set of FITS images of either the fields specified
or all the fields already in the object.
Parameters
----------
filename : string
The name of the FITS file to be written.
fields : list of strings
These fields will be pixelized and output. If "None", the keys of the
FRB will be used.
overwrite : boolean
If the file exists, this governs whether we will overwrite.
other_keys : dictionary, optional
A set of header keys and values to write into the FITS header.
units : string, optional
the length units that the coordinates are written in, default 'cm'.
"""
from yt.visualization.fits_image import FITSImageData
if fields is None:
fields = list(self.data.keys())
else:
fields = ensure_list(fields)
if len(fields) == 0:
raise RuntimeError(
"No fields to export. Either pass a field or list of fields to "
"export_fits or access a field from the fixed resolution buffer "
"object.")
fib = FITSImageData(self, fields=fields, units=units)
if other_keys is not None:
for k, v in other_keys.items():
fib.update_all_headers(k, v)
fib.writeto(filename, overwrite=overwrite, **kwargs)