Projection of a MNIST image (upper panel) on the HEALPix sphere. The same image is projected along the Equator (first row), around the north pole (second row) and at a random position on the sphere (third row). For each case, we show the map using the Mollweide projection (first column), an Orthographic projection centered on the Equator and at the north and south poles. The resolution of the projected maps corresponds to N_side = 16.