HEALPix: A Framework for High‐Resolution Discretization and Fast Analysis of Data Distributed on the Sphere

TLDR

HEALPix is a versatile data structure and library that enables fast scientific analysis and visualization of large spherical maps, originally developed for CMB experiments such as BOOMERanG and WMAP and designed to support future missions like Planck, Herschel, SAFIR, and the Beyond Einstein CMB polarization probe. This paper outlines the requirements and constraints for an efficient framework to discretize and analyze functions on the sphere, and shows how HEALPix meets those specifications.

Abstract

HEALPix -- the Hierarchical Equal Area iso-Latitude Pixelization -- is a versatile data structure with an associated library of computational algorithms and visualization software that supports fast scientific applications executable directly on very large volumes of astronomical data and large area surveys in the form of discretized spherical maps. Originally developed to address the data processing and analysis needs of the present generation of cosmic microwave background (CMB) experiments (e.g. BOOMERanG, WMAP), HEALPix can be expanded to meet many of the profound challenges that will arise in confrontation with the observational output of future missions and experiments, including e.g. Planck, Herschel, SAFIR, and the Beyond Einstein CMB polarization probe. In this paper we consider the requirements and constraints to be met in order to implement a sufficient framework for the efficient discretization and fast analysis/synthesis of functions defined on the sphere, and summarise how they are satisfied by HEALPix.