University of Southampton OCS (beta), CAA 2012

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Landscape change at Metaponto: a tale of two DEMs
Jessica Trelogan, Alessandro Rizzo, Esmeralda Moscatelli

Last modified: 2011-12-16

Abstract


This paper will present the preliminary results of a 3-year project, funded under NASA’s Space Archaeology Program (Grant No. NNX10AM37G), to investigate the use of remote sensing from space-based and airborne platforms to study ancient land management strategies at the ancient Greek agricultural territory (chora) of Metaponto in southern Italy. The focus here is on a monumental project of land reclamation conducted in the mid-fifth century BC, which was later echoed in the mid-20th century by a substantial bonifica (drainage and land reclamation project) that was intended to reestablish agricultural productivity in the modern region of Basilicata. The main goals of the project are 1) to further investigate, using remotely sensed imagery from space and from the air, evidence for  ancient land management strategies and their relationship with—and impact on—the natural environment, and 2) to compare ancient and modern land management (particularly drainage) systems to investigate the impact of both on the local topographic situation.

This paper will present initial results from a study of topographic changes that have resulted from an increase in mechanized agriculture in the region. These changes, which have seriously affected our ability to reconstruct the ancient landscape, will be tracked by a comparison of two digital terrain models, both extracted using photogrammetric techniques. The first DEM (which will, in a later stage of the project, serve as a proxy for the ancient terrain surface for hydrologic modeling) has been extracted from a set of historic aerial photographs from the 1950s. These photos, originally taken as part of a national Italian mapping project known as the “Volo Base,” covered the entire country at a nominal scale of 1:30,000. They have been used extensively for archaeological prospecting—including at Metaponto—but they have rarely been used for extracting elevation models. The second DEM, intended to represent the modern terrain surface, was also created from optical data (at 2.5 m resolution) acquired in 2006 by the Japanese satellite for stereo mapping, ALOS PRISM.

The two DEMs—comparable in scale and accuracies—will be compared to determine where, and how much, the local topography has been altered in recent history. The techniques of DEM extraction will be presented, as will the initial results of the comparison. Although the work is currently in its early stages, the results are extremely promising and have wide application for tracking changes that have direct impact on archaeological landscapes. 

 


Keywords


landscape change; remote sensing; ALOS PRISM; historic aerial photography; DEM extraction