Schiaparelli's Mappa Aerographica of Mars, Stereographic projection, 1877-78. Giovanni Virginio Schiaparelli (1835-1910) was an Italian astronomer and science historian. In 1888, Schiaparelli announced the discovery of a network of narrow lines on Mars, which he described as "canali," an Italian word that means "channels." In Italian, the word can mean a natural channel like a river valley. Stereographic projection is a particular mapping (function) that projects a sphere onto a plane. The projection is defined on the entire sphere, except at one point: the projection point. Where it is defined, the mapping is smooth and bijective.