hats.pixel_tree.pixel_tree

Classes

PixelTree

Sparse Quadtree of HEALPix pixels that make up the HATS catalog

Module Contents

class PixelTree(tree: numpy.ndarray, order: int)

Sparse Quadtree of HEALPix pixels that make up the HATS catalog

This class stores each node in the tree, with leaf nodes corresponding to pixels with data files.

There are a number of methods in this class which allow for quickly navigating through the tree and performing operations to filter the pixels in the catalog.

pixels

Nested dictionary of pixel nodes stored in the tree. Indexed by HEALPix order then pixel number

tree_order

tree

pixels

__len__()

Gets the number of nodes in the tree

Returns:

The number of nodes in the tree

contains(pixel: hats.pixel_math.HealpixPixel | tuple[int, int]) → bool

Check if tree contains a node at a given order and pixel

Parameters:

pixel – HEALPix pixel to check. Either of type HealpixPixel or a tuple of (order, pixel)

Returns:

True if the tree contains the pixel, False if not

__contains__(item)

get_max_depth() → int

Get the max depth (or highest healpix order) represented in the list of pixels.

Returns:

max depth (or highest healpix order) of the pixels in the tree

get_healpix_pixels() → list[hats.pixel_math.HealpixPixel]

Creates a list of HealpixPixels in the tree

Returns (List[HealpixPixel]):

A list of the HEALPix pixels in the tree

to_moc() → mocpy.MOC

Returns the MOC object that covers the same pixels as the tree

to_depth29_ranges() → numpy.ndarray

Returns the ranges of the pixels in the tree at depth 29

classmethod from_healpix(healpix_pixels: collections.abc.Sequence[hats.pixel_math.HealpixPixel | tuple[int, int]], tree_order=None) → PixelTree

Build a tree from a list of constituent healpix pixels

Parameters:

• healpix_pixels – list of healpix pixels

• tree_order (int) – (Default = None) order to generate the tree at. If None, will use the highest order from input pixels

Returns:

The pixel tree with the leaf pixels specified in the list