Detecting Roman land boundaries in aerial photographs using Radon transforms

Abstract

Remotely sensed images are a valuable resource for archaeological landscape studies. Historical aerial photographs, in particular, often contain important data, especially where recent landscape change has drastically altered topography. Within the current study area, focussed upon the alluvial landscape surrounding the ancient city of Butrint in southern Albania, late 20th century agricultural intensification has obliterated topographical features relating to earlier land-use within the valley. However, through recourse to earlier aerial photographic images and the development of an image analysis procedure utilizing Radon transforms, a study of relic landscape divisions relating to the Roman settlement and land-use at Butrint has been possible. The analytical procedure described allows the rapid, automated detection of linear alignments relating to the orientation of the settlement over large spatial areas. The resulting data were imported into a GIS, allowing measurements between surviving linear elements to be made and regular patterns of land division or centuriation deduced. The study revealed the surviving remnants of a centuriation pattern composed primarily of 20 actus divisions, while a further possibly earlier pattern was also detected, based upon 16 by 24 actus divisions.