The introduction to Geography states what Ptolemy wanted to accomplish, which includes an explanation of the principles of cartography such as giving coordinates to places around the world and geographic features as well as recommendations for making world and regional maps. He then starts his coverage of the world with Europe in Books 2 and 3. He goes on to cover Africa in Book 4 and covers Asia and summarizes his findings in Books 5-8. Geography included 26 colorized regional maps as well as one map of the "known world". Ptolemy stayed away from orthogonal (or cylindrical) world mapping in favor of three other projection types.
Importance of Ptolemy's Geography
Ptolemy's work has been discovered and used through the ages by several noted people around the world. Arabic writer al-Mas'udi, while writing around 956, mentioned a colored map of the Geography which had 4530 cities and over 200 mountains. Byzantine monk Maximus Planudes found a copy of the Geography in 1295, and since there were no maps in his copy, he drew his own based on the coordinates found in the text. The first Latin translation of the Geography was made in 1406 by Florentine Jacobus Angelus, and since this, various translations in other languages have been made available to people all over the world. However, the most important discovery of Ptolemy's Geography may have been made by Christopher Columbus. Columbus obtained one of the first Latin editions of the book (an edition printed in 1475) without the maps. We know that he definitely considered Ptolemy's distances while he was creating his own maps since his text of the Geography has some annotations in it and bears his signature (this text is currently in Madrid). In fact, scholars believe that Ptolemy's information may have encouraged Columbus to make his famous voyage.