HiPS catalogue tiles – content and visualisation. The content of a HiPS catalogue tile depends on how the source catalogue points are chosen to be distributed over the different HiPS orders. The upper panel shows three HiPS tiles of successive orders, with the lowest order tile on the left and sibling tiles to the right. The filled circles in the tiles represent catalogue sources that are “stored” in each tile, and the upper set of tiles represents a sequential view of these orders. Lower panel: the same three tiles but in this case we represent a cumulative view of the HiPS catalogue, where zooming into higher order tiles shows the sources in the tile plus the cumulative set of sources over all of the lower orders.