healpy.boundaries(nside, pix, step=1, nest=False)

Returns an array containing vectors to the boundary of the nominated pixel.

The returned array has shape (3, 4*step), the elements of which are the x,y,z positions on the unit sphere of the pixel boundary. In order to get vector positions for just the corners, specify step=1.

nside : int

The nside of the Healpix map.

pix : int

Pixel identifier

step : int, optional

Number of elements for each side of the pixel.

nest : bool, optional

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

boundary : float, array

x,y,z for positions on the boundary of the pixel