The following maps all show the spatial distribution of the letters of Libanius in different ways. The main difficulty while creating these maps was how to illustrate that the precise destination of several letters is unknown and that we merely know in which province they went. While trying to find the geographical data for the contours of the Roman provinces in the late fourth century, I realized that the data did not exist. This led to the inclusion of a new goal for this project: the creation of georeferenced polygons for all the Roman provinces where Libanius sent his letters. I chose to group divided provinces (such as Palestina Prima, Palestina Secunda and Palestina Salutaris) into one polygon for clarity and since it is not clear where the letters actually went. All of these maps were created using the Python mapping tool Folium.
The first Folium map follows a specific colour scheme to indicate how many letters went to each destination. Blue areas and markers indicate that less than 5 letters went there. Purple indicates that between 5 and 9 letters went there, while red indicates that more than 10 letters went there. Precisely known locations have been marked with a "pinpoint" marker, while imprecise locations were marked with "question mark" markers. For every question mark marker, the province is drawn around it with the matching colour.
To view the map, click on the image below.
The second Folium map utilizes the choropleth function, which colours the polygons according to colorbrewer's colour schemes. Given the limitations in terms of the different colours that a Folium marker can have, the markers still use the same colour scheme as the other maps.