Johann Bayer's star atlas and catalog, Uranometria, was the first of its kind. It represented a tremendous leap forward both esthetically and for its astronomical content, and became the standard for all later star atlases. Bayer's atlas was the first to portray the constellations as maps. Each plate has a carefully engraved grid so star positions can be determined precisely and used the star naming system that was adopted by later stellar cartographers. (Source: W. Ashworth, Out of This World.)