def read_map(filename,field=0,dtype=np.float64,nest=False,hdu=1,h=False,
verbose=False):
"""Read an healpix map from a fits file.
Parameters
----------
filename : str
the fits file name
field : int or tuple of int, optional
The column to read. Default: 0.
By convention 0 is temperature, 1 is Q, 2 is U.
Field can be a tuple to read multiple columns (0,1,2)
dtype : data type, optional
Force the conversion to some type. Default: np.float64
nest : bool, optional
If True return the map in NEST ordering, otherwise in RING ordering;
use fits keyword ORDERING to decide whether conversion is needed or not
If None, no conversion is performed.
hdu : int, optional
the header number to look at (start at 0)
h : boo, optional
If True, return also the header. Default: False.
verbose : bool, optional
If True, print a number of diagnostic messages
Returns
-------
m | (m0, m1, ...) [, header] : array or a tuple of arrays, optionally with header appended
The map(s) read from the file, and the header if *h* is True.
"""
hdulist=pf.open(filename)
#print hdulist[1].header
nside = hdulist[hdu].header.get('NSIDE')
if nside is None:
warnings.warn("No NSIDE in the header file : will use length of array",
HealpixFitsWarning)
else:
nside = int(nside)
if verbose: print 'NSIDE = %d'%nside
if not pixelfunc.isnsideok(nside):
raise ValueError('Wrong nside parameter.')
ordering = hdulist[hdu].header.get('ORDERING','UNDEF').strip()
if ordering == 'UNDEF':
ordering = (nest and 'NESTED' or 'RING')
warnings.warn("No ORDERING keyword in header file : "
"assume %s"%ordering)
if verbose: print 'ORDERING = %s in fits file'%ordering
sz=pixelfunc.nside2npix(nside)
if not hasattr(field, '__len__'):
field = (field,)
ret = []
for ff in field:
m=hdulist[hdu].data.field(ff).astype(dtype).ravel()
if (not pixelfunc.isnpixok(m.size) or (sz>0 and sz != m.size)) and verbose:
print 'nside=%d, sz=%d, m.size=%d'%(nside,sz,m.size)
raise ValueError('Wrong nside parameter.')
if not nest is None: # no conversion with None
if nest and ordering == 'RING':
idx = pixelfunc.nest2ring(nside,np.arange(m.size,dtype=np.int32))
m = m[idx]
if verbose: print 'Ordering converted to NEST'
elif (not nest) and ordering == 'NESTED':
idx = pixelfunc.ring2nest(nside,np.arange(m.size,dtype=np.int32))
m = m[idx]
if verbose: print 'Ordering converted to RING'
try:
m[pixelfunc.mask_bad(m)] = UNSEEN
except OverflowError, e:
pass
ret.append(m)
def read_map(filename, field=0, dtype=npy.float64, nest=False, hdu=1, h=False, verbose=False):
"""Read an healpix map from a fits file.
Input:
- filename: the fits file name
Parameters:
- field: the column to read Default: 0
by convention 0 is temperature, 1 is Q, 2 is U
field can be a tuple to read multiple columns (0,1,2)
- dtype: force the conversion to some type. Default: npy.float64
- nest=False: if True return the map in NEST ordering, otherwise in RING ordering;
use fits keyword ORDERING to decide whether conversion is needed or not
if None, no conversion is performed
- hdu=1: the header number to look at (start at 0)
- h=False: if True, return also the header
- verbose=False: if True, print a number of diagnostic messages
Return:
- an array, a tuple of array, possibly with the header at the end if h
is True
"""
hdulist = pyf.open(filename)
# print hdulist[1].header
nside = int(hdulist[hdu].header.get("NSIDE"))
if nside is None:
warnings.warn("No NSIDE in the header file : will use length of array", HealpixFitsWarning)
if verbose:
print "NSIDE = %d" % nside
if not pixelfunc.isnsideok(nside):
raise ValueError("Wrong nside parameter.")
ordering = hdulist[hdu].header.get("ORDERING", "UNDEF").strip()
if ordering == "UNDEF":
ordering = nest and "NESTED" or "RING"
warnings.warn("No ORDERING keyword in header file : " "assume %s" % ordering)
if verbose:
print "ORDERING = %s in fits file" % ordering
sz = pixelfunc.nside2npix(nside)
if not hasattr(field, "__len__"):
field = (field,)
ret = []
for ff in field:
m = hdulist[hdu].data.field(ff).astype(dtype).ravel()
if (not pixelfunc.isnpixok(m.size) or (sz > 0 and sz != m.size)) and verbose:
print "nside=%d, sz=%d, m.size=%d" % (nside, sz, m.size)
raise ValueError("Wrong nside parameter.")
if nest != None: # no conversion with None
if nest and ordering == "RING":
idx = pixelfunc.nest2ring(nside, npy.arange(m.size, dtype=npy.int32))
m = m[idx]
if verbose:
print "Ordering converted to NEST"
elif (not nest) and ordering == "NESTED":
idx = pixelfunc.ring2nest(nside, npy.arange(m.size, dtype=npy.int32))
m = m[idx]
if verbose:
print "Ordering converted to RING"
try:
m[pixelfunc.mask_bad(m)] = UNSEEN
except OverflowError, e:
pass
ret.append(m)
def in_ring(nside, iz, phi0, dphi, nest=False):
"""Compute the list of pixels in ring number iz in phi interval [phi0,phi0+dphi]
Input:
- nside: a power of 2
- iz: ring number
- phi0: the starting longitude
- dphi: interval of longitude
Keyword:
- nested: if True, return pixel number in nested scheme. Default: False (RING)
Return:
- list of pixel numbers
"""
from numpy import pi, arange, concatenate, hstack, fabs, round
from pixelfunc import nside2npix, ring2nest
npix = nside2npix(nside)
take_all = 0
to_top = 0
twopi = 2.0 * pi
ncap = 2 * nside * (nside - 1)
listir = -1
nir = 0
phi_low = (phi0 - dphi) % twopi
if (phi_low < 0): phi_low = phi_low + twopi
phi_hi = (phi0 + dphi) % twopi
if (phi_hi < 0): phi_hi = phi_hi + twopi
if (fabs(dphi - pi) < 1e-6): take_all = 1
# equatorial region
if ((iz >= nside) & (iz <= 3 * nside)):
ir = iz - nside + 1
ipix1 = ncap + 4 * nside * (ir - 1)
ipix2 = ipix1 + 4 * nside - 1
kshift = ir % 2
nr = nside * 4
else:
if (iz < nside):
ir = iz
ipix1 = 2 * ir * (ir - 1)
ipix2 = ipix1 + 4 * ir - 1
else:
ir = 4 * nside - iz
ipix1 = npix - 2 * ir * (ir + 1)
ipix2 = ipix1 + 4 * ir - 1
nr = ir * 4
kshift = 1
if (take_all == 1):
nir = ipix2 - ipix1 + 1
listir = arange(ipix1, ipix2 + 1, 1)
if (take_all == 0):
shift = kshift * .5
ip_low = int(round(nr * phi_low / twopi - shift))
ip_hi = int(round(nr * phi_hi / twopi - shift))
ip_low = ip_low % nr
ip_hi = ip_hi % nr
if (ip_low > ip_hi): to_top = 1
ip_low = ip_low + ipix1
ip_hi = ip_hi + ipix1
if (to_top == 1):
nir1 = ipix2 - ip_low + 1
nir2 = ip_hi - ipix1 + 1
nir = nir1 + nir2
if ((nir1 > 0) & (nir2 > 0)):
#listir = concatenate(arange(0,nir2,1)+ipix1, arange(0,nir1,1)+ip_low)
list1 = arange(0, nir1, 1) + ip_low
list2 = arange(0, nir2, 1) + ipix1
listir = concatenate((list1, list2))
else:
if (nir1 == 0): listir = arange(0, nir2, 1) + ipix1
if (nir2 == 0): listir = arange(0, nir1, 1) + ip_low
else:
nir = ip_hi - ip_low + 1
listir = arange(0, nir, 1) + ip_low
if (nest): listir = ring2nest(nside, listir)
return listir
def in_ring(nside,iz,phi0,dphi,nest=False):
"""Compute the list of pixels in ring number iz in phi interval [phi0,phi0+dphi]
Input:
- nside: a power of 2
- iz: ring number
- phi0: the starting longitude
- dphi: interval of longitude
Keyword:
- nested: if True, return pixel number in nested scheme. Default: False (RING)
Return:
- list of pixel numbers
"""
from numpy import pi,arange,concatenate,hstack,fabs,round
from pixelfunc import nside2npix,ring2nest
npix = nside2npix(nside)
take_all = 0
to_top = 0
twopi = 2.0 * pi
ncap = 2*nside*(nside-1)
listir = -1
nir = 0
phi_low = (phi0 - dphi) % twopi
if (phi_low < 0): phi_low = phi_low + twopi
phi_hi = (phi0 + dphi) % twopi
if (phi_hi < 0): phi_hi = phi_hi + twopi
if (fabs(dphi-pi) < 1e-6): take_all = 1
# equatorial region
if ((iz >= nside) & (iz <= 3*nside)):
ir = iz - nside + 1
ipix1 = ncap + 4*nside*(ir-1)
ipix2 = ipix1 + 4*nside - 1
kshift = ir % 2
nr = nside*4
else:
if (iz < nside):
ir = iz
ipix1 = 2*ir*(ir-1)
ipix2 = ipix1 + 4*ir - 1
else:
ir = 4*nside - iz
ipix1 = npix - 2*ir*(ir+1)
ipix2 = ipix1 + 4*ir - 1
nr = ir*4
kshift = 1
if (take_all == 1):
nir = ipix2 - ipix1 + 1
listir = arange(ipix1,ipix2+1,1)
if (take_all == 0):
shift = kshift * .5
ip_low = int(round (nr * phi_low / twopi - shift))
ip_hi = int(round(nr * phi_hi / twopi - shift))
ip_low = ip_low % nr
ip_hi = ip_hi % nr
if (ip_low > ip_hi): to_top = 1
ip_low = ip_low + ipix1
ip_hi = ip_hi + ipix1
if (to_top == 1):
nir1 = ipix2 - ip_low + 1
nir2 = ip_hi - ipix1 + 1
nir = nir1 + nir2
if ((nir1 > 0) & (nir2 > 0)):
#listir = concatenate(arange(0,nir2,1)+ipix1, arange(0,nir1,1)+ip_low)
list1 = arange(0,nir1,1)+ip_low
list2 = arange(0,nir2,1)+ipix1
listir = concatenate((list1,list2))
else:
if (nir1 == 0) : listir = arange(0,nir2,1)+ipix1
if (nir2 == 0) : listir = arange(0,nir1,1)+ip_low
else:
nir = ip_hi - ip_low + 1
listir = arange(0,nir,1)+ip_low
if (nest): listir = ring2nest(nside,listir)
return listir
def read_map(filename,
field=0,
dtype=npy.float64,
nest=False,
hdu=1,
h=False,
verbose=False):
"""Read an healpix map from a fits file.
Input:
- filename: the fits file name
Parameters:
- field: the column to read Default: 0
by convention 0 is temperature, 1 is Q, 2 is U
field can be a tuple to read multiple columns (0,1,2)
- dtype: force the conversion to some type. Default: npy.float64
- nest=False: if True return the map in NEST ordering, otherwise in RING ordering;
use fits keyword ORDERING to decide whether conversion is needed or not
if None, no conversion is performed
- hdu=1: the header number to look at (start at 0)
- h=False: if True, return also the header
- verbose=False: if True, print a number of diagnostic messages
Return:
- an array, a tuple of array, possibly with the header at the end if h
is True
"""
hdulist = pyf.open(filename)
#print hdulist[1].header
nside = int(hdulist[hdu].header.get('NSIDE'))
if nside is None:
warnings.warn("No NSIDE in the header file : will use length of array",
HealpixFitsWarning)
if verbose: print 'NSIDE = %d' % nside
if not pixelfunc.isnsideok(nside):
raise ValueError('Wrong nside parameter.')
ordering = hdulist[hdu].header.get('ORDERING', 'UNDEF').strip()
if ordering == 'UNDEF':
ordering = (nest and 'NESTED' or 'RING')
warnings.warn("No ORDERING keyword in header file : "
"assume %s" % ordering)
if verbose: print 'ORDERING = %s in fits file' % ordering
sz = pixelfunc.nside2npix(nside)
if not hasattr(field, '__len__'):
field = (field, )
ret = []
for ff in field:
m = hdulist[hdu].data.field(ff).astype(dtype).ravel()
if (not pixelfunc.isnpixok(m.size) or
(sz > 0 and sz != m.size)) and verbose:
print 'nside=%d, sz=%d, m.size=%d' % (nside, sz, m.size)
raise ValueError('Wrong nside parameter.')
if nest != None: # no conversion with None
if nest and ordering == 'RING':
idx = pixelfunc.nest2ring(nside,
npy.arange(m.size, dtype=npy.int32))
m = m[idx]
if verbose: print 'Ordering converted to NEST'
elif (not nest) and ordering == 'NESTED':
idx = pixelfunc.ring2nest(nside,
npy.arange(m.size, dtype=npy.int32))
m = m[idx]
if verbose: print 'Ordering converted to RING'
try:
m[pixelfunc.mask_bad(m)] = UNSEEN
except OverflowError, e:
pass
ret.append(m)
def read_map(filename,field=0,dtype=npy.float64,nest=False,hdu=1,h=False):
"""Read an healpix map from a fits file.
Input:
- filename: the fits file name
Parameters:
- field: the column to read Default: 0
by convention 0 is temperature, 1 is Q, 2 is U
field can be a tuple to read multiple columns (0,1,2)
- dtype: force the conversion to some type. Default: npy.float64
- nest=False: if True return the map in NEST ordering, otherwise in RING ordering;
use fits keyword ORDERING to decide whether conversion is needed or not
if None, no conversion is performed
- hdu=1: the header number to look at (start at 0)
- h=False: if True, return also the header
Return:
- an array, a tuple of array, possibly with the header at the end if h
is True
"""
hdulist=pyf.open(filename)
#print hdulist[1].header
nside = int(hdulist[hdu].header.get('NSIDE'))
if nside is None:
warnings.warn("No NSIDE in the header file : will use length of array",
HealpixFitsWarning)
print 'NSIDE = %d'%nside
if not pixelfunc.isnsideok(nside):
raise ValueError('Wrong nside parameter.')
ordering = hdulist[hdu].header.get('ORDERING','UNDEF').strip()
if ordering == 'UNDEF':
ordering = (nest and 'NESTED' or 'RING')
warnings.warn("No ORDERING keyword in header file : "
"assume %s"%ordering)
print 'ORDERING = %s in fits file'%ordering
sz=pixelfunc.nside2npix(nside)
if not hasattr(field, '__len__'):
field = (field,)
ret = []
for ff in field:
m=hdulist[hdu].data.field(ff).astype(dtype).ravel()
if not pixelfunc.isnpixok(m.size) or (sz>0 and sz != m.size):
print 'nside=%d, sz=%d, m.size=%d'%(nside,sz,m.size)
raise ValueError('Wrong nside parameter.')
if nest != None: # no conversion with None
if nest and ordering == 'RING':
idx = pixelfunc.nest2ring(nside,npy.arange(m.size,dtype=npy.int32))
m = m[idx]
print 'Ordering converted to NEST'
elif (not nest) and ordering == 'NESTED':
idx = pixelfunc.ring2nest(nside,npy.arange(m.size,dtype=npy.int32))
m = m[idx]
print 'Ordering converted to RING'
m[m<-1.637e30] = UNSEEN
ret.append(m)
if len(ret) == 1:
if h:
return ret[0],hdulist[hdu].header.items()
else:
return ret[0]
else:
if h:
ret.append(hdulist[hdu].header.items())
return tuple(ret)
else:
return tuple(ret)