First published in Nuremberg, as here, in 

's ‘Speculum Solis' - Mirror of the Sun - a book about sundials. 



 (died 1641) was born in Nuremberg, and all that is known of him, beyond that, is his keen interest in scientific and navigational instruments, as witnessed by his book on sundials, the ‘Speculum Solis’, or Mirror of the Sun.

’s gnomonic map not only are lines of longitude straight, but any great circle line of bearing is straight as well. The landmasses are drawn to scale in proportion to their distance from the pole. The result is a very distorted, though mathematically correct, projection. Ritter's world map is projected from Nuremberg, with its lines of longitude arrayed to serve also as hour lines suitable for a sundial. Based on the precise unique gnomonic projection for each location of the sundial, lines of bearing could be drawn with an extended piece of string. The map is surrounded by ten diagrams that show how to measure and record the passage of time. 

 (c. 1570–1641) was from Nuremberg and studied under Johann Praetorius at the University of Altdorf. Ritter specialized in the design and manufacture of astrolabes, sundials, and other astronomical, horological, and cartographical instruments. Ritter earns a mention in Johann Doppelmayr’s 1730 catalogue of Nuremberg mathematicians and artists. He published several works on astrolabes, including, in 1640, an illustrated folio explaining each component of the instrument. His ‘Instructio Instrumentalis Quadrantis Novi’ (1597), noteworthy for its attempt to accommodate the curvature of the earth with irregular, curved guidelines, was reprinted at least ten times in the next seventy-five years. His ‘Speculum Solis’ (‘Mirror of the Sun’) from which this map derives, was a work on sundials that contained unusual maps on gnomonic projection. Ritter's plates for Speculum Solis were intended to be used as sundials, hence very few have survived.

 was a mathematician from Nuremberg who published the first map on a gnomonic projection. An ancient technology used by Greek mariners as early as the sixth century BCE, this projection displays all great circles as straight lines, resulting in any straight-line segment showing a geodesic, the shortest route between the segment's two endpoints. 

Ritter's plates for maps were intended to be used as sundials, hence very few have survived. Based on the precise unique gnomonic projection for each location of the sundial, lines of bearing could be drawn with an extended piece of string. The map is surrounded by ten diagrams that show how to measure and record the passage of time.

This highly unusual map shows the world projected from the North Pole as if it were the table of a sundial. The point of a sundial is called a gnomon, and this projection is therefore known as a gnomonic of sundial projection. The landmasses are drawn to scale in proportion to their distance from the pole. The result is a very distorted, though mathematically correct, projection. The map is surrounded by horological diagrams that show ways to measure and record the passage of time.

Double-page engraved copperplate map of the world, on a gnomonic (central), or sundial, projection. 

Ritter's World Map, on a sundial projection with diagrams on recording the passage of time