GIS on The Diros Project, Greece
It's 7:00 in the morning. The sun has already crested the mountains to the east, and the temperature is on the rise. By 2:00, it will be over 100 degrees Fahrenheit. The members of the survey team are lacing their boots and gathering water, snacks, and other supplies before heading out into the field for the day. Their task is to collect all the ceramics, tile fragments, stone tools, and other artifacts that they see strewn across the ground and bring them back to the lab for more detailed analysis.
The survey team is part of The Diros Project, a Greek-American collaborative archaeological project headed by Drs. Giorgos Papathanassopoulos (Greek Ministry of Culture), Anastasia Papathanasiou (Greek Ministry of Culture), William Parkinson (The Field Museum) and Michael Galaty (Millsaps College). Although the project is focused on a Neolithic cave site called Alepotrypa (or “Fox-Hole” cave), one of its goals is to understand how people used the landscape outside the cave. The team accomplishes this by using GIS software to interpret data collected from archaeological survey and excavation.
Figure 1. Distribution of ceramics collected during survey (with GeoEye-1 imagery). All maps by Rebecca Seifried.
While the survey team is out in the field, others are busy at work conducting excavation. One group is working inside the cave, continuing the archaeological work that began in the 1970s. The material they recover is hauled into the laboratory to be analyzed and recorded, far outnumbering the few pieces retrieved from survey. Meanwhile, another group is busy just outside the entryway to the cave. This team is preoccupied with the perplexing situation they have uncovered during their excavation – the more dirt they remove from their unit, the more human bones appear. Digging in the earth behind a terrace wall, they are discovering an astounding number of Neolithic artifacts and a few human burials that are very likely associated with the material inside the cave nearby.
All of these data are incorporated into a geographic information system (GIS) database to visualize the distribution of artifacts, burials, and other finds across the landscape. In 2011 and 2012, the survey team collected a total of 330 “tracts” - sections of land crudely defined by rubble walls, roads, and other features visible from the air and on maps. GIS software can then be used to map clusters of artifacts (in red, Figure 1). The team then employed intensive gridded collection at the promontory just outside the cave entrance, where an especially high number of Neolithic ceramics were found. In part, this intensive collection helped them determine where to place two excavation units in the 2012 season (Figure 2).
Figure 2. Intensive collection and excavations on the promontory
Another project that has been completed with the help of GIS software is the mapping of the interior of Alepotrypa Cave. A detailed map had already been created using AutoCAD software, but importing it into GIS allowed the map to be “georeferenced,” assigning coordinates to known locations inside the cave. Next, we created a digital elevation model (DEM) of the large interior chamber using data collected at points inside the cave. Together, the georeferenced map and DEM can be used to map excavation units and findspots inside the cave, and understand how their spatial distribution and changes in elevation may be related.
Figure 3. Alepotrypa Cave
For more information on The Diros Project, check out http://fieldmuseum.org/explore/diros.