Modeling Transportation in the Roman World: Implications for World Systems

Abstract

ORBIS is a geospatial transportation network model of the Roman world, simulating historical travel patterns by modeling the major roads, rivers, and sea routes active during the Roman Empire. With such a model, historians can more accurately examine not only individual route patterns, but also emergent structures of the network as a whole. By defining traditional world systems networks as a particular movement profile for application on a geospatial transportation network, we can begin to see regions of the network using community analysis and analyze those regions for historical patterns.World Systems [1] has represented networks of exchange-whether of goods, people, or information-in various ways, most of them not resembling traditional network graphs and following ChaseDunn and Hall's theoretically and visually uncomplicated format that emphasizes the nested nature of bulk goods, political-military, prestige goods, and information networks. While this format is useful to demonstrate a global connectedness that allows for the exchange of goods, people, and ideas, it is less useful for understanding the regional disconnectedness implied by the very same movement. With the development of sophisticated historical geo-spatial transportation network models, such as ORBIS [2], the variation in regional expression of network communities based on the different priorities implied by the movement of goods, people, and ideas can be more formally analyzed and represented.ORBIS was built by combining existing accounts of sites and routes of the Roman period as represented in Pleiades [3] and the Barrington Atlas [4], combined with modern river tracks and sea routes derived using a computational model calibrated with historical accounts [5]. The result is a simplified model of the Roman transportation network that is subject to seasonal modification based on route cost change and availability due to changing winds, currents, heavy seas, or winter inaccessibility of certain mountain roads.

A virtual water network of the Roman world

“…5b), consistent with the finding that poor infrastructure increases import costs (Limão and Venables, 2001). However in Orbis, lower-degree nodes are generally located inland where import costs are also higher owing to the difficulties in transporting large quantities of grain overland by horse and cart compared with ship (Braudel, 1995;Limão and Venables, 2001;Meeks, 2013;Scheidel, 2013). To isolate the effect of node degree from edge cost we simulated VW redistribution with the same network structure but reassigned edge costs and VW values at nodes randomly in each simulation year (Fig.…”

“…Orbis, the Stanford Geospatial Network of the Roman World forms the basis for our VW redistribution network of the Roman world (Meeks, 2013;Scheidel, 2013). Orbis broadly reflects the transport network in the Roman Empire around AD 200 with all links confirmed as Roman era transport routes although we cannot be certain that all were active in AD 200.…”