Exposing the Peutinger Diagram

I recently announced a project to study how the late antique Peutinger Diagram was made. This reverse engineering project is comparable to lifting the hood/bonnet of a sleek car in the hope of understanding the mechanical principles by which it was built and operates.

The first step is to create a digital version of the Peutinger Diagram on which we can overlayer the findings as we accumulate them. My starting point is the digital projection of the Diagram created by Professor Richard J. A. Talbert’s team for the 2010 book Rome’s World: The Peutinger Map Reconsidered (Map A).

This projection is a panorama photograph after images of the 12th-century parchment pieces of the sole surviving copy had been stitched together digitally and slightly skewed so that everything matches up.

The result was a banana-shaped image that is not very practicable in full-screen view, so I have straightened the Talbert projection, inserting a single hinge about one third of the way from the left. The left and right tips of the panorama were raised a total of 2.85 degrees with respect to one another.
The pivot point is located at Cesena, Italy and roads and rivers in the vicinity have been adjusted accordingly but the slight shifts are in no way egregious, being well below the diagram's threshold of geographical accuracy.

The second step was to create a scalable vector graphic (SVG) file based on this projection. I began by merging a selection of SVG files which are stored online at the Ancient World Mapping Center in and employed in the Talbert Map Viewer and pivoted these in the same way. I soon found however that they are not very satisfactory from a SVG-design point of view, being full of transforms, unsuitable data objects, data cruft, broken lines and many tracing errors.

I have almost entirely retraced by hand the photographic image with a great many simplifications. This adaptation will provide us a compact, interactive, fast-loading data-file similar to that I have published for the Great Stemma. I have retained the Talbert colour coding system and some of his data objects. Acknowledgement to the Talbert team's work will appear on the new file.

The third step is to match this new data view of the Tabula with the past scholarship, whereby Konrad Miller's 1916 book, Itineraria Romana, is the great monument. Miller, a German citizen-scholar who died in 1933, analysed the diagram into its key routes, effectively recasting its data into list form. What I am now doing is mapping Miller's routes as an over-layer onto the SVG file.

The results will be uploaded as I go to the project page on ResearchGate. Keep visiting the project page to see the progress. Collaborators and followers are very welcome.