healpy.pixelfunc.ang2pix¶

healpy.pixelfunc.ang2pix(nside, theta, phi, nest=False)¶

ang2pix : nside,theta[rad],phi[rad],nest=False -> ipix (default:RING)

Parameters :

nside : int, scalar or array-like

The healpix nside parameter, must be a power of 2

theta, phi : float, scalars or array-like

Angular coordinates of a point on the sphere

nest : bool, optional

if True, assume NESTED pixel ordering, otherwise, RING pixel ordering

Returns :

pix : int or array of int

The healpix pixel numbers. Scalar if all input are scalar, array otherwise. Usual numpy broadcasting rules apply.

See also

Examples

>>> import healpy as hp
>>> hp.ang2pix(16, np.pi/2, 0)
1440

>>> hp.ang2pix(16, [np.pi/2, np.pi/4, np.pi/2, 0, np.pi], [0., np.pi/4, np.pi/2, 0, 0])
array([1440,  427, 1520,    0, 3068])

>>> hp.ang2pix(16, np.pi/2, [0, np.pi/2])
array([1440, 1520])

>>> hp.ang2pix([1, 2, 4, 8, 16], np.pi/2, 0)
array([   4,   12,   72,  336, 1440])