healpy.pixelfunc.ud_grade¶
- healpy.pixelfunc.ud_grade(map_in, nside_out, pess=False, order_in='RING', order_out=None, power=None, dtype=None)¶
Upgrade or degrade resolution of a map (or list of maps).
in degrading the resolution, ud_grade sets the value of the superpixel as the mean of the children pixels. Note that ud_grade can create artifacts in the power spectra and should be avoided unless the specific application can tolerate that.
- Parameters:
- map_inarray-like or sequence of array-like
the input map(s) (if a sequence of maps, all must have same size)
- nside_outint
the desired nside of the output map(s)
- pessbool
if
True
, in degrading, reject pixels which contains a bad sub_pixel. Otherwise, estimate average with good pixels- order_in, order_outstr
pixel ordering of input and output (‘RING’ or ‘NESTED’)
- powerfloat
if non-zero, divide the result by (nside_in/nside_out)**power Examples: power=-2 keeps the sum of the map invariant (useful for hitmaps), power=2 divides the mean by another factor of (nside_in/nside_out)**2 (useful for variance maps)
- dtypetype
the type of the output map
- Returns:
- map_outarray-like or sequence of array-like
the upgraded or degraded map(s)
Examples
>>> import healpy as hp >>> hp.ud_grade(np.arange(48.), 1) array([ 5.5 , 7.25, 9. , 10.75, 21.75, 21.75, 23.75, 25.75, 36.5 , 38.25, 40. , 41.75])