Modeling the Distant Past
Rachel Opitz, a research associate at the University of Arkansas’ Center for Advanced Spatial Technologies, is spending a large chunk of her summer at ancient ruins in the Mediterranean.
CAST is collaborating with four ongoing projects that focus on the development of urbanism around the Mediterranean. These collaborations include teaching 3-D modeling and digital recording and survey techniques to field school students at Kalavasos – Ayios Dhimitrios in Cyprus and at Gabii in Italy and using terrestrial laser scanning at Vulci in Italy and Malthi in Greece. Laser scanning allows Opitz to collect and analyze billions of measurements which provide detailed 3-D perspectives of both buried remains and structures on the surface at these sites.
All of the projects are attempts to understand how these places became urban and investigate the social dynamics of urbanization. At the root of any such study is a detailed and accurate record of what is preserved at the site – the walls and roads and floor surfaces – along with the robbers pits, soil washed downslope and irrigation trenches that later disturbed or buried them. Support for collecting these fundamental data are provided at Malthi and Vulci by awards made through SPatial Archaeometry Research Collaborations – CAST’s National Science Foundation-funded effort to promote the use of geospatial technologies in archaeological research.
Work at Kalavasos – Ayios Dhimitrios in Cyprus and at Gabii in Italy is supported by the Social Sciences and Humanities Research Council in Canada and a variety of public and private sources, including the National Endowment for the Humanities.
Opitz described her field research in dispatches from Cyprus and Greece:
“At Kalavasos – Ayios Dhimitrios in Cyprus, I worked with Kevin Fisher, a former CAST researcher now at the University of British Columbia, to get the excavation team started with the ‘new normal’ of digital excavation. I worked with the project’s staff to develop an excavation database and a workflow for documenting with digital photogrammetry every stratigraphic unit – the physical remains of an individual action in the past, such as laying the gravel bed for a road. Digital photogrammetry, also known as structure from motion, is a technique that allows us to create 3-D models based on the information contained in a set of regular photographs and some basic information about the camera used to take them. This technique is becoming increasingly standard in archaeological recording at excavations.
“The goal of the KAMBE project is trying to understand the development of this Late Bronze Age urban center, and in particular they are interested in the use of space and movement through the site. So the layout of buildings and roads – spatial information – is particularly important for their research. I worked with the staff to train the project’s field school students in using the new system to record what they were finding as they began to excavate. An essential part of this is documenting the relative position of each structure uncovered on the site by creating geo-referenced 3-D models of them.”
“At Vulci, I worked with Emanuele Casagrande Cicci of Sapienza University in Rome, collecting data in close cooperation with the core project team led by Maurizio Forte of Duke University. While Forte’s team deployed an unmanned aerial vehicle-based survey to map the overall topography and layout of Vulci, we used terrestrial laser scanning to make a detailed model of the topography of the urban center where the remains of buildings sit just below the surface.
“By processing the terrestrial laser scanning data to remove the vegetation and manipulating it to highlight minute differences in elevation we were able to identify the remains of subsurface walls, and to trace out the probable outlines of buildings and roads. The evidence from the microtopographic survey is being combined with the results of multi-instrument surveys undertaken by various collaborators coordinated by Maurizio Forte’s team at Duke University. This includes ground penetrating radar survey, currently underway, magnetometry survey, imagery from the ongoing unmanned aerial vehicle-based survey, and one fantastic 1980s aerial photograph taken in a particularly good moment for crop marks.
“The intensive prospection work at the site is intended to lay the groundwork for future study of the urban core of the site, and to answer questions about how the organization of the town changed over time.
“At Malthi in Greece, we used terrestrial laser scanning to map the remains of the architecture present on the surface of a hilltop fortified settlement that was previously excavated in the early 20th century but not well-documented. The research team, led Rebecca Worsham and Donald Haggis at the University of North Carolina at Chapel Hill and Michael Lindblom at Uppsala University in Sweden, hopes to understand the organization of the structures – fortification walls, rooms, doorways, infant graves, column bases and terraces. These remains are now so partial and jumbled together with the spoil heaps and stone mounds left by previous excavations, and walls built to contain sheep, that the original plan of the town is hard to understand on the ground.
“The detailed documentation provided through the terrestrial laser scanning survey, together with careful descriptions of the remains, many photographs, and a differential global positioning system survey of identifiable features, will be studied by the research team as they attempt to piece together the original arrangement and character of this hilltop settlement.”
Opitz is now in central Italy, joining the long-term excavations at Gabii, a town with roots in the Iron Age that grew into a thriving regional center during the Roman Republic, and then began to shrink during the Roman Imperial period, eventually becoming farmland and empty fields.
The Gabii Project, involving more than 60 students and staff, is uncovering large swaths of the town’s center, and the evidence coming to light about private, public and industrial activities is helping us to understand the trajectory of growth and decline in a town that grew up alongside Rome.