Healpix is an acronym for hierarchical equal area isolatitude pixelization of a sphere. as suggested in the name, this pixelization produces a subdivision of a spherical surface in which each pixel covers the same surface area as every other pixel. it is commonly used to store all-sky astronomical images, most famously maps of the cosmic microwave background.

this package provides the dynamic library for the c++ language implementation of healpix. it can be used interactively via python bindings available in a separate package. the c++ library provides input/output, basic spatial operations such as conversion between spherical coordinates and healpix pixels, and also sophisticated spatial operations such as querying cones or polygons, as well as upsampling/downsampling, smoothing, and fast spherical harmonic transforms.