Ptolemy ' s Geography : An Annotated Translation of the Theoretical Chapters

University Press. All rights reserved. No part of this book may be reproduced in any form by any electronic or mechanical means (including photocopying, recording, or information storage and retrieval) without permission in writing from the publisher, except for reading and browsing via the World Wide Web. Users are not permitted to mount this file on any network servers. Introduction Ptolemy's Geography is a treatise on cartography, the only book on that subject to have survived from classical antiquity. Like Ptolemy's writings on astronomy and optics, the Geography is a highly original work, and it had a profound influence on the subsequent development of geographical science. From the Middle Ages until well after the Renaissance, scholars found three things in Ptolemy that no other ancient writer supplied: a topography of Europe, Africa, and Asia that was more detailed and extensive than any other; a clear and succinct discussion of the roles of astronomy and other forms of data-gathering in geographical investigations; and a well thought out plan for the construction of maps. Ptolemy himself would not have claimed that the Geography was original in all these aspects. He tells us that the places and their arrangement in his map were mostly taken over from an earlier cartographer, Marinos of Tyre. Again, Ptolemy comprehended fully the superior value of astronomical observations over reported itineraries for determining geographical locations, but in this he was, on his own admission, anticipated by other geographers, notably Hipparchus three centuries earlier. 1 Even so, he was too far ahead of his time in maintaining this principle to be able to follow it in practice, because he possessed reliable astronomical data for only a handful of places. But in the technique of map-making Ptolemy claims to break new ground. He introduced the practice of writing down coordinates of latitude and longitude for every feature drawn on a world map, so that someone else possessing only the text of the Geography could reproduce Ptolemy's map at any time, in whole or in part, and at any scale. He was apparently also the first to devise sophisticated map projections with a view to giving the visual impression of the earth's curvature while at the same time preserving to a limited extent the relative distances between various localities. At the very outset of the Geography, Ptolemy describes his subject as " an imitation through drawing of the entire known part …