healpy.query_disc

healpy.query_disc(nside, vec, radius, inclusive=False, fact=4, nest=False, ndarray buff=None)

Returns pixels whose centers lie within the disk defined by vec and radius (in radians) (if inclusive is False), or which overlap with this disk (if inclusive is True).

Parameters:

nside : int

The nside of the Healpix map.

vec : float, sequence of 3 elements

The coordinates of unit vector defining the disk center.

radius : float

The radius (in radians) of the disk

inclusive : bool, optional

If False, return the exact set of pixels whose pixel centers lie within the disk; if True, return all pixels that overlap with the disk, and maybe a few more. Default: False

fact : int, optional

Only used when inclusive=True. The overlapping test will be done at the resolution fact*nside. For NESTED ordering, fact must be a power of 2, less than 2**30, else it can be any positive integer. Default: 4.

nest: bool, optional

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

buff: int array, optional

if provided, this numpy array is used to contain the return values and must be at least long enough to do so

Returns:

ipix : int, array

The pixels which lie within the given disk.