How to use the pixell.enmap.pix2sky function in pixell

def make_projectable_map_cyl(map, verbose=False):
	"""Given an enmap in a cylindrical projection, return a map with
	the same pixelization, but extended to cover a whole band in phi
	around the sky. Also returns the slice required to recover the
	input map from the output map."""
	# First check if we need flipping. Sharp wants theta,phi increasing,
	# which means dec decreasing and ra increasing.
	flipx = map.wcs.wcs.cdelt[0] < 0
	flipy = map.wcs.wcs.cdelt[1] > 0
	if flipx: map = map[...,:,::-1]
	if flipy: map = map[...,::-1,:]
	# Then check if the map satisfies the lat-ring requirements
	ny, nx = map.shape[-2:]
	vy,vx = enmap.pix2sky(map.shape, map.wcs, [np.arange(ny),np.zeros(ny)])
	hy,hx = enmap.pix2sky(map.shape, map.wcs, [np.zeros(nx),np.arange(nx)])
	dx    = hx[1:]-hx[:-1]
	dx    = dx[np.isfinite(dx)] # Handle overextended coordinates

	if not np.allclose(dx,dx[0]): raise ShapeError("Map must have constant phi spacing")
	nphi = utils.nint(2*np.pi/dx[0])
	if not np.allclose(2*np.pi/nphi,dx[0]): raise ShapeError("Pixels must evenly circumference")
	if not np.allclose(vx,vx[0]): raise ShapeError("Different phi0 per row indicates non-cylindrical enmap")
	phi0 = vx[0]
	# Make a map with the same geometry covering a whole band around the sky
	# We can do this simply by extending it in the positive pixel dimension.
	oshape = map.shape[:-1]+(nphi,)
	owcs   = map.wcs
	# Our input map could in theory cover multiple copies of the sky, which
	# would require us to copy out multiple slices.
	nslice = (nx+nphi-1)//nphi

def get_rotated_pixels(shape_source, wcs_source, shape_target, wcs_target,
                       inverse=False, pos_target=None,
                       center_target=None, center_source=None):
    """ Given a source geometry (shape_source,wcs_source)
    return the pixel positions in the target geometry (shape_target,wcs_target)
    if the source geometry were rotated such that its center lies on the center
    of the target geometry.

    WARNING: Only currently tested for a rotation along declination
    from one CAR geometry to another CAR geometry.
    """
    # what are the center coordinates of each geometries
    if center_source is None:
        center_source = enmap.pix2sky(
            shape_source, wcs_source,
            (shape_source[0] / 2., shape_source[1] / 2.))
    if center_target is None:
        center_target = enmap.pix2sky(
            shape_target, wcs_target,
            (shape_target[0] / 2., shape_target[1] / 2.))
    decs, ras = center_source
    dect, rat = center_target
    # what are the angle coordinates of each pixel in the target geometry
    if pos_target is None:
        pos_target = enmap.posmap(shape_target, wcs_target)
    #del pos_target
    # recenter the angle coordinates of the target from the target center
    # to the source center
    if inverse:
        transfun = lambda x: coordinates.decenter(x, (rat, dect, ras, decs))

def make_projectable_map_cyl(map, verbose=False):
	"""Given an enmap in a cylindrical projection, return a map with
	the same pixelization, but extended to cover a whole band in phi
	around the sky. Also returns the slice required to recover the
	input map from the output map."""
	# First check if we need flipping. Sharp wants theta,phi increasing,
	# which means dec decreasing and ra increasing.
	flipx = map.wcs.wcs.cdelt[0] < 0
	flipy = map.wcs.wcs.cdelt[1] > 0
	if flipx: map = map[...,:,::-1]
	if flipy: map = map[...,::-1,:]
	# Then check if the map satisfies the lat-ring requirements
	ny, nx = map.shape[-2:]
	vy,vx = enmap.pix2sky(map.shape, map.wcs, [np.arange(ny),np.zeros(ny)])
	hy,hx = enmap.pix2sky(map.shape, map.wcs, [np.zeros(nx),np.arange(nx)])
	dx    = hx[1:]-hx[:-1]
	dx    = dx[np.isfinite(dx)] # Handle overextended coordinates

	if not np.allclose(dx,dx[0]): raise ShapeError("Map must have constant phi spacing")
	nphi = utils.nint(2*np.pi/dx[0])
	if not np.allclose(2*np.pi/nphi,dx[0]): raise ShapeError("Pixels must evenly circumference")
	if not np.allclose(vx,vx[0]): raise ShapeError("Different phi0 per row indicates non-cylindrical enmap")
	phi0 = vx[0]
	# Make a map with the same geometry covering a whole band around the sky
	# We can do this simply by extending it in the positive pixel dimension.
	oshape = map.shape[:-1]+(nphi,)
	owcs   = map.wcs
	# Our input map could in theory cover multiple copies of the sky, which
	# would require us to copy out multiple slices.
	nslice = (nx+nphi-1)//nphi
	islice, oslice = [], []

center_target=None, center_source=None):
    """ Given a source geometry (shape_source,wcs_source)
    return the pixel positions in the target geometry (shape_target,wcs_target)
    if the source geometry were rotated such that its center lies on the center
    of the target geometry.

    WARNING: Only currently tested for a rotation along declination
    from one CAR geometry to another CAR geometry.
    """
    # what are the center coordinates of each geometries
    if center_source is None:
        center_source = enmap.pix2sky(
            shape_source, wcs_source,
            (shape_source[0] / 2., shape_source[1] / 2.))
    if center_target is None:
        center_target = enmap.pix2sky(
            shape_target, wcs_target,
            (shape_target[0] / 2., shape_target[1] / 2.))
    decs, ras = center_source
    dect, rat = center_target
    # what are the angle coordinates of each pixel in the target geometry
    if pos_target is None:
        pos_target = enmap.posmap(shape_target, wcs_target)
    #del pos_target
    # recenter the angle coordinates of the target from the target center
    # to the source center
    if inverse:
        transfun = lambda x: coordinates.decenter(x, (rat, dect, ras, decs))
    else:
        transfun = lambda x: coordinates.recenter(x, (rat, dect, ras, decs))
    res = coordinates.transform_meta(transfun, pos_target[1::-1], fields=["ang"])
    pix_new = enmap.sky2pix(shape_source, wcs_source, res.ocoord[1::-1])

def get_pixsize_rect(shape, wcs):
    """Return the exact pixel size in steradians for the rectangular cylindrical
    projection given by shape, wcs. Returns area[ny], where ny = shape[-2] is the
    number of rows in the image. All pixels on the same row have the same area."""
    ymin = enmap.sky2pix(shape, wcs, [-np.pi / 2, 0])[0]
    ymax = enmap.sky2pix(shape, wcs, [np.pi / 2, 0])[0]
    y = np.arange(shape[-2])
    x = y * 0
    dec1 = enmap.pix2sky(shape, wcs, [np.maximum(ymin, y - 0.5), x])[0]
    dec2 = enmap.pix2sky(shape, wcs, [np.minimum(ymax, y + 0.5), x])[0]
    area = np.abs((np.sin(dec2) - np.sin(dec1)) * wcs.wcs.cdelt[0] * np.pi / 180)
    return area

def get_pixsize_rect(shape, wcs):
    """Return the exact pixel size in steradians for the rectangular cylindrical
    projection given by shape, wcs. Returns area[ny], where ny = shape[-2] is the
    number of rows in the image. All pixels on the same row have the same area."""
    ymin = enmap.sky2pix(shape, wcs, [-np.pi / 2, 0])[0]
    ymax = enmap.sky2pix(shape, wcs, [np.pi / 2, 0])[0]
    y = np.arange(shape[-2])
    x = y * 0
    dec1 = enmap.pix2sky(shape, wcs, [np.maximum(ymin, y - 0.5), x])[0]
    dec2 = enmap.pix2sky(shape, wcs, [np.minimum(ymax, y + 0.5), x])[0]
    area = np.abs((np.sin(dec2) - np.sin(dec1)) * wcs.wcs.cdelt[0] * np.pi / 180)
    return area