Development of Map-making among the Greeks.—Ionian mercenaries and traders arrived in Egypt, on the invitation of Psammetichus I., about the middle of the 7th century B.C. One of the most distinguished was Thales of Miletus B.c.), the founder of the Ionian school of philosophy, whose pupil, Anax imander (611-546 B.c.) is credited by Eratosthenes with having designed the first map of the world. Anaximander looked upon the earth as a section of a cylinder, of considerable thickness, suspended in the centre of the circular vault of the heavens, an idea perhaps from the Babylonians (see Job xxvi. 7). Like Homer he looked upon the habitable world as being circular in outline and bounded by a circumfluent river. The geographical knowledge of Anaximander extended from the Cassiterides or Tin islands in the west to the Caspian in the east, which he conceived to open out into Oceanus. The Aegean sea occupied the centre of the map, while the line where ocean and firmament seemed to meet represented an enlarged horizon.
Anaximenes, a pupil of Anaximander, was the first to reject the view that the earth was a circular plane, but held it to be an oblong rectangle, buoyed up in the midst of the heavens by the compressed air upon which it rested.
The map of the world brought upon the stage in Aristophanes' The Clouds (423 B.c.), whereon a disciple of the Sophists points out Athens and other places known to the audience, was prob ably of the popular circular type, which Herodotus (iv. 36) not many years before had derided and which was discarded by Greek cartographers ever after. Thus Democritus of Abdera (b. c. 450, d. after 36o), the great philosopher and founder, with Leucippus, of the atomic theory, was also the author of a map of the inhabited world which he supposed to be half as long again from west to east, as it was broad.
Dicaearcus of Messana in Sicily, a pupil of Aristotle (326-296 B.c.), is the author of a topographical account of Hellas, with maps, of which only fragments are preserved; he is credited with having estimated the size of the earth, and, as far as known he was the first to draw a parallel across a map. The map of Dicaearcus resembled that of Democritus.
Scientific geography profited largely from the labours- of Eratosthenes of Cyrene, whom Ptolemy Euergetes appointed keeper of the famous library of Alexandria in 247 B.C., and died in that city in 195 B.C. He won fame as having been the first to determine the size of the earth by a scientific method. Having determined the difference of latitude between Alexandria and Syene which he erroneously believed to lie on the same meridian, and obtained the distance of those places from each other from the surveys made by Egyptian geometers, he concluded that a degree of the meridian measured 700 stadia.
Eratosthenes is the author of a treatise which deals systemat ically with the geographical knowledge of his time, but of which only fragments have been preserved by Strabo and others. This treatise was intended to illustrate and explain his map of the world. In this task he was much helped by the materials collected in his library. His map formed a parallelogram measuring 75,800 stadia from Usisama (Ushant island) or Sacrum Promontorium in the west to the mouth of the Ganges and the land of the Coniaci (Comorin) in the east, and 46,000 stadia from Thule in the north to the supposed southern limit of Libya. Across it were drawn seven parallels, running through Meroe, Syene, Alexandria, Rhodes, Lysimachia on the Hellespont, the mouth of the Borys thenes and Thule, and these were crossed at right angles by seven meridians, drawn at irregular intervals. In his text Eratos thenes ignored the popular division of the world into Europe, Asia and Libya, and substituted for it a northern and southern division, divided by the parallel of Rhodes, each of which he subdivided into sphragides or plinthia—seals or plinths. The principles on which these divisions were made remain an enigma to the present day. This map of Eratosthenes, notwithstanding its many errors, such as the assumed connection of the Caspian with a northern ocean and the supposition that Carthage, Sicily and Rome lay on the same meridian, enjoyed a high reputation in his day. Even Strabo (c. 3o B.c.) adopted its main features.
Hipparchus, the famous astronomer, on the other hand (c. I5o B.c.) proved a somewhat captious critic. He justly objected to the arbitrary network of the map of Eratosthenes. The paral lels or climata drawn through places, of which the longest day is of equal length and the decimation (distance) from the equator is the same, he maintained, ought to have been inserted at equal intervals, say of half an hour, and the meridians inserted on a like principle. In fact, he demanded that maps should be based upon a regular projection, several descriptions of which he had adopted for his star maps. He moreover accuses Eratosthenes (whose determination of a degree he accepts without hesitation) with trusting too much to hypothesis in compiling his map instead of having recourse to latitudes and longitudes deduced by as tronomical observations. Such observations, however, were but rarely available at the time. Hipparchus is not known to have compiled a map himself.