Fig 1.
Location of area of interest (smaller map) and geographical distributions of selected municipalities and milestones used in this study, along with Roman road network.
See sections 2.3 and S1 Appendix 4 for details. Third party data sources: Background topography by Natural Earth Project [59] (public domain); Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.
Fig 2.
Temporal evolution of one realisation of the spreading process represented as a spreading tree.
Green nodes indicate the initially Romanised municipalities at 0 AD and blue nodes municipalities that have a Roman status in the respective time frame. Each connected component of the spreading tree is a tree rooted in a green node. These trees indicate how the municipalities got influenced. Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.
Fig 3.
Roman roads in ancient Tunisia.
Left: Scaled down image of the Roman road network. Right: The Roman road network, where red nodes resemble settlements and black edges road segments. Generic road nodes are omitted. Sources: Natural Earth [59]; Ancient World Mapping Center (AWMC) [60, 85]. Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.
Fig 4.
Left: Example of a spreading tree. Right: Roads in the Roman road network that correspond to the spreading tree shown in the left figure. Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.
Fig 5.
Projection to the road network.
Left: Probabilities of example road segments indicated by the colour map. Municipalities on the right were Romanised before those on the left. Right: Schematic illustration of the road activation procedure. Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.
Fig 6.
Temporal activation probabilities of the road segments.
The influence function is chosen as in Model 1 by π(p, c) = exp(−0.08 ⋅ dp,c). Romanised municipalities are marked in red. Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.
Fig 7.
Shift in the road activation probabilities wrt.
Model 1 when including the municipality status in the influence function. White roads denote a good fit between the two models, red roads indicate higher activation probability in Model 2 and blue roads higher activation probability in Model 1. Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.
Fig 8.
Temporal activation probabilities of the road segments obtained using the distance influence function, plotted together with milestones (red triangles).
Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.
Fig 9.
Temporal activation probability of the road segments around the milestones.
Milestones that were found in the same location are grouped in one image. The time frames the respective milestones were found are marked in grey. Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.
Fig 10.
Temporal mean squared error between and α(e).
Romanised municipalities are marked in red. Roman roads network lines reproduced with permission from Ancient World Mapping Center [61] under a CC BY licence, original copyright 2015.
Fig 11.
Temporal squared distance when excluding the city of Cillium (top) and respectively Mactaris (bottom) from the model.
The city excluded is marked in red. Roman roads network lines reproduced with permission from Ancient World Mapping Center [60] under a CC BY licence, original copyright 2015.