class Skymap(object):
_defaults = (
# 512 has a pixel size of ~0.11 deg
('nside', 128, 'Healpix nside' ),
('coord', 'gal', 'Coordinate frame' ),
)
def __init__(self, *args, **kwargs):
self._load(**kwargs)
self.roster = Roster(*args)
def _load(self, **kwargs):
kw = dict([(d[0],d[1]) for d in self._defaults])
kw.update(kwargs)
self.__dict__.update(kw)
def fill(self):
self.values = np.zeros(hp.nside2npix(self.nside))
self.pix = np.arange(hp.nside2npix(self.nside))
self.lon,self.lat = pix2ang(self.nside,self.pix)
for target in self.roster.values():
print(target)
if self.coord == 'gal':
idx = query_disc(self.nside,target.glon,target.glat,target.psi_max)
lon,lat = gal2cel(self.lon[idx],self.lat[idx])
else:
idx = query_disc(self.nside,target.ra,target.dec,target.psi_max)
lon,lat = self.lon[idx],self.lat[idx]
self.values[idx] += target.jvalue(lon,lat)
class Skymap(object):
"""Object to fill a HEALPix sky-map with J values from a `Roster`
"""
def __init__(self, *targets, **kwargs):
"""C'tor
Parameters
----------
targets : list
List of objects to include in this map
Keyword arguments
-----------------
nside : int
HEALPix n-side parameter [512]
coord : str
Coordinate system 'cel' or 'gal' ['gal']
"""
self.nside = kwargs.get('nside', 512)
self.coord = kwargs.get('coord', 'gal')
self.values = np.zeros(hp.nside2npix(self.nside))
self.pix = np.arange(hp.nside2npix(self.nside))
self.lon, self.lat = pix2ang(self.nside, self.pix)
self.roster = Roster(*targets)
self._fill()
def _fill(self):
"""Fills map values """
for target in self.roster.values():
print(target)
if self.coord == 'gal':
idx = query_disc(self.nside, target.glon, target.glat,
target.psi_max)
lon, lat = gal2cel(self.lon[idx], self.lat[idx])
else:
idx = query_disc(self.nside, target.ra, target.dec,
target.psi_max)
lon, lat = self.lon[idx], self.lat[idx]
self.values[idx] += target.jvalue(lon, lat)
class Skymap(object):
"""Object to fill a HEALPix sky-map with J values from a `Roster`
"""
def __init__(self, *targets, **kwargs):
"""C'tor
Parameters
----------
targets : list
List of objects to include in this map
Keyword arguments
-----------------
nside : int
HEALPix n-side parameter [512]
coord : str
Coordinate system 'cel' or 'gal' ['gal']
"""
self.filename = kwargs.get('filename', None)
if self.filename is None:
self._construct(*targets, **kwargs)
else:
self._read_fits(filename)
def _construct(self, *targets, **kwargs):
self.nside = kwargs.get('nside', 512)
self.coord = kwargs.get('coord', 'gal')
self.ann = kwargs.get('ann', True)
if self.ann:
self.units = 'GeV^2 cm^5 s^-2'
else:
self.units = 'GeV cm^3'
self.values = np.zeros(hp.nside2npix(self.nside))
self.pix = np.arange(hp.nside2npix(self.nside))
self.lon, self.lat = pix2ang(self.nside, self.pix)
self.roster = Roster(*targets)
self._fill()
def _fill(self):
"""Fills map values """
for target in self.roster.values():
print(target)
if self.coord == 'gal':
idx = query_disc(self.nside, target.glon, target.glat, target.psi_max)
lon, lat = gal2cel(self.lon[idx], self.lat[idx])
else:
idx = query_disc(self.nside, target.ra, target.dec, target.psi_max)
lon, lat = self.lon[idx], self.lat[idx]
if self.ann:
self.values[idx] += target.jvalue(lon, lat)
else:
self.values[idx] += target.dvalue(lon, lat)
def write_fits(self, filename, overwrite=True):
"""Write this Skymap to a FITS file"""
col = fits.Column(name='Bin0', format='1D', array=self.values)
header = fits.Header()
header['COORDSYS'] = self.coord
header['COORDTYPE'] = self.coord
header['ORDERING'] = 'RING'
header['INDXSCHM'] = 'IMPLICIT'
header['NSIDE'] = self.nside
header['ORDER'] = nside_to_order(self.nside)
header['FIRSTPIX'] = 0
header['LASTPIX'] = len(self.values) - 1
header['HPX_CONV'] = 'GALPROP'
header['BANDSHDU'] = ''
primhdu = fits.PrimaryHDU()
skyhdu = fits.BinTableHDU.from_columns([col], header=header, name='SKYMAP')
hdulist = fits.HDUList([primhdu, skyhdu])
hdulist.writeto(filename, overwrite=overwrite)
def _assert_header_key(self, header, key, value):
"""Internal method to verify that a FITS header key matches the expected value"""
check = header.get(key)
if check != value:
raise ValueError("Header card %s=%s it should be %s" % (key, check, value))
def _read_fits(self, filename):
"""Internal method to read this from a FITS file"""
f = fits.open(filename)
header = f[1].header
self._assert_header_key(header, 'HPX_CONV', 'GALPROP')
self._assert_header_key(header, 'ORDERING', 'RING')
self._assert_header_key(header, 'INDXSCHM', 'IMPLICIT')
self.nside = header['NSIDE']
self.coord = header['COORDSYS']
self.values = np.zeros(hp.nside2npix(self.nside))
self.pix = np.arange(hp.nside2npix(self.nside))
self.lon, self.lat = pix2ang(self.nside, self.pix)
self.values = f[2].data.field('Bin0')