International Conference on GPR in Archaeology (Nara, February 2001)

Large Scale GPR Surveys on Roman Buildings

Wolfgang Neubauer

Specialising in archaeological prospecting and mainly carrying out contract work we use an integrated approach combining aerial photography, magnetics, resistivity and ground penetrating radar (GPR). All kind of prospection data are digitally combined for subsequent archaeological interpretation in a geographical information system (GIS). A research project in cooperation with the Vienna Institute for Archaeological Science in 1998 aimed in the development of software for fast processing and visualising GPR data. For surveying we use a PulseEKKO 1000 device with 250, 450 or 900 MHz antennas. The data are normally collected in a raster of 0.5 x 0.05 or 0.5 x 0.1 m prospecting up to 5000 squaremeters per day. The data are visualised as B&W time or depth slices. These digital images are georeferenced and imported into the GIS for archaeological interpretation. To get an impression on the data and to form a mental interpretation model the slices are animated providing a better understanding of the complex threedimensional structures.

During the last two years various Roman sites in Austria and abroad were prospected using GPR. We present some case studies and discuss problems of interpreting archaeological GPR data. The case studies include a variety of Roman buildings in urban and rural environment. Best known is the forum of the Roman town Carnuntum east of Vienna detected by a 5 ha resistivity survey in 1996. The final GPR results (3 ha) visualising the forum with three major halls, the open square with tabernae, a basilica, a temple and the neighbouring insulae are presented. Situated beside a main road entering the town another large building complex was investigated. It seems to be a mansio providing bed, food and other forms of recreation for the travellers visiting Carnuntum. We compare this urban mansio with a Roman station at the main road from Mediolanum crossing the Alps and leading to Brigantium situated at the Lake of Constanz. The mansio and mutatio was called Clunia is known from the Tabula Peutingeriana, a map representing the world as known by the Romans. A large scale GPR survey (5 ha) recovered a extended mansio and a mutatio beside the Roman road together with stables, barns, granaries and a small temple. The GPR data indicates an earlier phase of the site visible by animation of the depth slices. Similar complex stratigraphic situations are documented by a recent GPR survey (4 ha) at the Roman town Flavia Solva south of Graz. Additional magnetic surveys showed astonishing limitiations of GPR method to detect walls built with bricks we would like to discuss. Comparing the results from Roman towns and rural sites we try to show the importance of an integrated archaeological prospection approach and ways for fast processing of huge amounts of GPR data. 

Return to conference page