Ptolemy's map

The Ptolemy world map is a map of the world known to Greco-Roman societies in the 2nd century. It is based on the description contained in Ptolemy's book '' Geography'', written . Based on an inscription in several of the earliest surviving manuscripts, it is traditionally credited to Agathodaemon of Alexandria.

Notable features of Ptolemy's map is the first use of longitudinal and latitudinal lines as well as specifying terrestrial locations by celestial observations. The ''Geography'' was translated from Greek into Arabic in the 9th century and played a role in the work of al-Khwārizmī before lapsing into obscurity. The idea of a global coordinate system revolutionized European geographical thought, however, and inspired more mathematical treatment of cartography.

Ptolemy's work probably originally came with maps, but none have been discovered. Instead, the present form of the map was reconstructed from Ptolemy's coordinates by Byzantine monks under the direction of Maximus Planudes shortly after 1295. It probably was not that of the original text, as it uses the ''less'' favored of the two alternate projections offered by Ptolemy.

Continents

The continents are given as Europe, Asia, and Libya (Africa). The World Ocean is only seen to the west. The map distinguishes two large enclosed seas: the Mediterranean and the Indian (''Indicum Pelagus''). Due to Marinus and Ptolemy's mistaken measure of the circumference of the earth, the former is made to extend much too far in terms of degrees of arc; due to their reliance on Hipparchus, they mistakenly enclose the latter with an eastern and southern shore of unknown lands, which prevents the map from identifying the western coast of the World Ocean.

India is bound by the Indus and Ganges rivers, but its peninsula is much shortened. Instead, Sri Lanka ('' Taprobane'') is greatly enlarged. The Malay Peninsula is given as the Golden Chersonese instead of the earlier "Golden Island", which derived from Indian accounts of the mines on Sumatra. Beyond the Golden Chersonese, the Great Gulf (''Magnus Sinus'') forms a combination of the Gulf of Thailand and South China Sea which is bound by the unknown lands thought to enclose the Indian Sea. China is divided into two realms—the Qin (''Sinae'') and the Land of Silk (''Serica'')—owing to the different accounts received from the overland and maritime Silk Roads.

The ''Geography'' and the map derived from it probably played an important role in the expansion of the Roman Empire to the East. Trade throughout the Indian Ocean was extensive from the 2nd century, and many Roman trading ports have been identified in India. From these ports, Roman embassies to China are recorded in Chinese historical sources from around 166.

The Danish historian Gudmund Schütte attempted to reconstruct the Danish part of Ptolemy's world map. It includes several place- and tribe-names, some of which Schütte assigned a contemporary equivalent. The most prominent feature of the map is the peninsula Jutland placed north of the river ''Albis Trêva'', west of the ''Saxonôn'' Nesôi ( archipelago), east of the ''Skandiai'' Nêsoi, which itself lies west of a larger island ''Skandia''. ''Skandia'' is home to the '' Goutai'' in the center, and the '' Phiraisoi'' in the east.

North of Jutland lies a third archipelago ''Alokiai'' Nêsoi. South of the ''Albis'' live the '' Lakkobardoi'' and to its north the ''Saxones''. The west coast of Jutland is home to the ''Sigulônes'', the ''Sabaliggio'', the ''Kobandoi'', the ''Eundusioi'' and the northernmost ''Kimbroi'' (possibly Cimbri). North and east is home to the ''Kimbrikê'' (possibly Cimbri), the ''Chersonêsos'' and the ''Charudes''.

References

External links

Ptolemaic images
at the European Library


the first to use Ptolemy's 2nd projection, at the University of Minnesota


at Columbia University

Richard Donohue's presentation of Ptolemy's projection with modern geographic knowledge

GIS Analysis and Digital Reconstruction of Ptolemy's India beyond the Ganges, Serike and Sinae

Iterative Reconstruction of Ptolemy’s West Africa Using Modern GIS Analysis

Visualization and GIS Analysis of Ptolemy’s One-Sided Globe in the Old and Modern Contexts

{{cartography topics

World map
Historic maps of the world
Foreign relations of ancient Rome
2nd-century works