HiPS: a hierarchical scheme for the description, storage and
access of sky survey data. The system is based on hierarchical tiling of sky
regions at finer and finer spatial resolution which facilitates a progressive
view of a survey, and supports multi-resolution zooming and panning. HiPS uses
the HEALPix tessellation of the sky as the basis for the scheme and is
implemented as a simple file structure with a direct indexing scheme that
leads to practical implementations.
