My interest in ancient coordinates began with the purchase of a copy of Ptolemy’s „Cosmographia“ in October 1991 for 39.80 German marks. I bought it at the former antiquarian bookstore Hermann Laatzen, which was located roughly halfway between Hamburg’s Jungfernstieg and the university. Essentially, the oversized volume consisted of impressive reproductions of maps from a parchment manuscript held by the National Library in Naples. The striking worldview unfolding on the maps piqued my curiosity.
It took about 25 years before the opportunity arose to examine the coordinates and their transmission more closely, and it took another ten years, with numerous interruptions, before results emerged from a wide variety of considerations and examinations. To achieve this, the scope of the investigation had to be significantly expanded on several occasions. It thus becomes apparent that the mathematical calculation of coordinates is incomplete as long as the linguistic analysis of the designations is neglected. This gave rise to the broad scope of the work, which ranges from ancient metrology and modern geodetic calculation methods to the linguistic interpretation of the text corpus.
What this work still lacks is a classification within modern lines of research. Naturally, this work also stands on the shoulders of those that came before it. This applies above all to the German-language edition of Ptolemy’s Handbook of Geography by Alfred Stückelberger and Gerd Grasshoff, which serves as the foundation for further research.
This study was made possible by technological developments in recent years. On the one hand, a geographic information system such as QGIS, which was used here, is indispensable for processing coordinates and measurement points. On the other hand, the results would not have been achievable without the digital availability of the surviving manuscripts, which are made available online by the Vatican.
The results of this work are intended for both interested laypeople and scholars engaged with the ancient world. Since this essentially involves the analysis—or, one might say, the “deciphering”—of a body of sources that is now legible, research interest from a wide variety of disciplines is conceivable.
The data is made available on these pages for scholarly use and may be utilized in accordance with standard academic citation practices. If you use the results of this work, please send a copy of your work via email to research (at) measuringtheantiqueworld.net.
Hamburg, den 24. Mai 2026, Gunnar Eisold