Several possible equal‐area isolatitude tessellations of the sphere, which can support a hierarchical tree for the further subdivision of each large base‐resolution pixel. Six variants of such a tessellation are shown here for several values of the grid parameters N_θ and N_φ. θ refers to the colatitude and φ to the longitude. For each panel two projections are shown: the top one is orthographic, the bottom one is cylindrical. θ_* defines the line of constant colatitude that separates the equatorial region from the northern polar region. This is shown by the top curve in the orthographic plot; also shown is the corresponding curve separating the equatorial and southern polar regions, as well as the equator. The HEALPix implementation is described by ﹩N_{\theta }=3﹩ and ﹩N_{\phi }=4﹩.