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

The paper introduces HEALPix, the Hierarchical Equal Area isoLatitude Pixelization, a versatile structure for pixelizing data distributed on the sphere, together with an associated library of computational algorithms and visualization software. The design simultaneously enables efficient discretization with hierarchical indexation and fast analysis and synthesis of functions defined on the sphere, allowing scientific applications to run directly on discretized spherical maps generated from very large volumes of astronomical data.

HEALPix was originally developed to meet the data processing and analysis needs of cosmic microwave background experiments such as BOOMERANG and WMAP, but the authors argue it can be expanded to future missions and experiments including Planck, Herschel, SAFIR, and the Beyond Einstein inflation probe. The paper lays out the requirements and implementation constraints for such a framework and demonstrates explicitly how HEALPix satisfies them, making it a lasting foundation for spherical data analysis.