Remote Sensing and GIS Modelling of Roman Roads in South West Britain

The recent availability of a systematic airborne LiDAR coverage for England in the scope of the Environment Agency’s ‘National LiDAR Programme’ has enabled the mapping of a new Roman road network system in South West Britain, an area where there was little solid evidence for a system of long-distance roads. To understand the rationale behind their construction, a GIS spatial analysis approach to model movement was developed, which included not just straightforward Least Cost Paths, but also other methods, such as MADO and CMTC, to overcome some of the common limitations of Least Cost Paths and produce a more reliable prediction of the likely layout of the Roman road network in the area. The results indicate that this network privileged the movement of animal-drawn wheel vehicles, avoiding where possible areas subject to flooding risks. This road network is possibly the result of an evolutionary model, integrating pre-existing Prehistoric routeways with Roman military and civilian roads, most of which were probably still in use in Medieval times.