healpy.pixelfunc.npix2nside¶
- healpy.pixelfunc.npix2nside(npix)¶
Give the nside parameter for the given number of pixels.
Parameters: npix : int
the number of pixels
Returns: nside : int
the nside parameter corresponding to npix
Notes
Raise a ValueError exception if number of pixel does not correspond to the number of pixel of an healpix map.
Examples
>>> import healpy as hp >>> hp.npix2nside(768) 8
>>> np.all([hp.npix2nside(12 * nside**2) == nside for nside in [2**n for n in range(12)]]) True
>>> hp.npix2nside(1000) Traceback (most recent call last): ... ValueError: Wrong pixel number (it is not 12*nside**2)