Digging into Archaeology

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Working on an archaeological excavation (or "dig") can be both thrilling and tedious. A dig can reveal artifacts and structures that provide important new information about the people who lived thousands or millions of years ago. But the work to find, document and sometimes remove the objects and other evidence of ancient human activity can be slow and difficult. Workers must carefully describe and catalog all items to preserve accurate records of the site and provide reliable data for subsequent scientific work.

One of the most important parts of an object’s archaeological or paleontological record is its context: where it was found, in what materials, and how it relates to other objects. For example, the location of objects in relation to fire pits, graves or water sources may give clues to the activities and daily life of ancient humans. For these researchers, it’s essential to gather an archaeological artifact’s context information while it is in its original location. Similarly, paleontologists say that a fossil’s context can reveal as much information as the fossil itself. In the best case, the data from excavations should enable scientists to reconstruct a site in three dimensions.

Collecting context information requires the field teams, who often may be students or volunteers, to keep detailed notes on their finds. Historically, workers kept handwritten notes in field books, clipboards and binders. Site workers often collected photographs and sketches, which would later be manually matched with written records. An object’s location could be determined by using pocket tapes and hand levels to measure from reference points. In many locations, a site coordinate grid system could be marked using string lines, with the location of objects referenced to the grid squares.

While recording context and location data is an essential task, it’s time-consuming and presents opportunities for errors and missing information. Gaps and inconsistencies can degrade the historical record and introduce uncertainty into the scientific work. Recognizing this, Antoni Canals, a researcher and professor of prehistory at the University of Rovira i Virgili (URV) in Spain, set out to improve the efficiency and accuracy of gathering data on archaeological sites. "The idea first arose in 1992," Canals said. "At that time, field data was recorded on paper. The notes were often inconsistent, which presented challenges for the field archaeologists as well as researchers in labs and offices." He set out to solve the problem.

Canals’ objective was straightforward and aggressive. He would develop a system to mechanize and computerize the recording of archaeological data, taking special care in determining an object’s 3D coordinates. Canals envisioned using the new technology of the time, personal digital assistants (PDA), to eliminate the exotic and inconsistent descriptions of objects. By combining standardized data collection forms with localized wireless communications, Canals could significantly streamline onsite data collection and management. To measure an object’s position, Canals’ idea called for replacing the string line grids with precise surveying equipment.

Canals’ system, named ARCH-e, would benefit two groups of people. First, it significantly improved the quality of information collected in the field while making excavation and cataloging move faster and more smoothly. Second, the electronic data format reduced errors and ensured the use of controlled protocols for registering and handling the evidence.

The development initially focused on collecting attribute information about the objects using PDAs. Canals spent more than a decade working on the software. He needed to match common field procedures with requirements for recording and preserving information in a system that could work in often challenging physical environments. The advent of rugged PDAs such as the Trimble Slate provided the field-capable platforms for the handheld software. One of the biggest challenges came in implementing the collection of 3D positioning.

In 2009, Canals began working with Al-Top Topografia S.A, a Trimble dealer in Spain. Drawing on Al-Top experience and with support from Trimble, Canals was able to connect ARCH-e to Trimble robotic total stations. This connection enabled field crews to quickly measure and record an object’s location and then return to their core tasks of unearthing, identifying and describing the object. The total stations provided an essential component of the system that provides a comprehensive, on-site solution for capturing and managing scientific data. As a result, the flow of archaeological data has transformed into a smooth, reliable process. More importantly, because ARCH-e automates the positioning and data management tasks, field teams can put their full attention to the scientific endeavors.

The key to the system comes from Canals’ intimate knowledge of the work processes. On the site, material is removed to uncover the archaeological artifacts. Using a PDA, a worker creates a field record describing the artifact, its taxonomic identification, orientation and measurements. The PDA connects to the onsite computer server via a dedicated local Wi-Fi network. To record an object’s position, ARCH-e uses a Trimble robotic total station to measure the position and send the coordinates to the server.

When all of the information has been collected and verified, the data is sent to the field server and the object can be packaged for travel to the laboratory. The field system even prints labels to identify the objects. Using multiple PDAs, one person at the server can monitor data coming from everyone on the site. At the end of each day, the field server database is transferred to a general database off site.

The security and reliability of the data is an essential component of archaeological and paleontological excavations. Once an object has been moved, its context is lost and can’t be exactly recreated. So field teams must be sure that the information is complete and correct before anything can be removed and packaged. In addition to descriptive records, workers can capture photographs and video using built-in cameras; linking the image files directly to each object’s record. ARCH-e uses standardized forms and checkboxes to guide the workers in the data entry process, and the daily offsite backup provides a high level of data integrity.

The ARCH-e system is now at work at research sites in Europe. These include the Archaeological Site of Atapuerca, which is a World Heritage Site and among Europe’s most important archaeo-paleontological locations. The system is also operating at field projects of the Catalan Institute of Human Paleoecology and Social Evolution (IPHES).

As a researcher and archaeologist, Canals is pleased with the results. "The project is not finished," he said, "and we will continue to open up new ways to make our work more efficient. But even today ARCH-e represents an important approach to improve the technical and methodological system of capturing and recording field data for Pleistocene archeological excavations. On a personal level, I have a modern tool, practical and efficient in my work. But I also believe that the system will improve the work of many archaeologists worldwide."

Carl Morton is a writer specializing in the geomatics, civil engineering and construction industries. Drawing on his extensive training and experience, Morton focuses on applications and innovations in equipment, software and techniques.

A 5.714Mb PDF of this article as it
appeared in the magazine—complete with images—is available by clicking HERE