“Dotting the joins”: a non-reconstructive use of Least Cost Paths to approach ancient roads. The case of the Roman roads in the NW Iberian Peninsula

The use of GIS tools to explore questions related to movement in archaeological contexts has been common in the last years. Least Cost Paths (LCP) have been especially successful among them, most often with the objective of predicting or reconstructing the layout of ancient routes. In this paper we propose an alternate use of those tools, aimed at trying to identify the main locations taken into account when defining the routes, rather than at predicting or reconstructing them. Through a rather simple and straightforward methodological sequence, based on the successive testing of very explicit hypotheses, we show how this approach can produce significant new knowledge while dodging some typical issues of LCP analysis. We illustrate the approach with the case study of the Roman roads in the north-west Iberian Peninsula.