Geographer and mathematician, the founder of mathematical geography, flourished in the 2nd century A.D. He lived before Ptolemy, who acknowledges his great obligations to him. His chief merits were that he assigned to each place its proper latitude and longtitude, and introduced improvements in the construction of his maps. He also carefully studied the works of his predecessors and the diaries of travellers. His geographical treatise is lost.
See A. Forbiger, Handbuch der alien Geographie, vol. i. (1842); E. H. Bunbury, Hist. of Ancient Geography (1879), ii. p. 519; and especially E. H. Berger, Geschichte der wissenschaftlichen Erdkunde der Griechen (1903).