Interdisciplinary Mapping in Archaeology; Guest Blog

Saralyn Smith

Archaeology and geology seem to me to be sisters of history, with one focused on writing the story of us, and when the ink runs out, the other takes up the pen to travel as far as the Hadeon Eon when our young Earth was an uninhabitable molten rock. It stands to reason that these disciplines hold common goals: understanding the past, interpreting past events, and exploration of the unknown. Since dipping my toes into the scientific world, I have often employed this married fabric in my studies, the latest being my excursion with the Heritage and Archaeological Research Practice in Scotland in August 2022.

After landing at Edinburgh Airport, the group of us rookie archaeologists were taken to Pitlochry, a town in the heart of Scotland along the bends of River Tummel. Here, we used each weekday to traverse the surrounding forests for the hidden historic roads under the tree cover. The most notable of these roads was a section of Wade’s Military Roads, the endeavouring builds under the direction of General George Wade with the hopes of quelling the Jacobite Rebellion in the early 1700s. Our archaeological teams used GPS to take the locations of these visible sections of earth-covered roads, as well as the measurements of widths and lengths, then returned to our camp to map these points and measurements in computer software.

QGIS, a free geographic information software program, is used to edit and analyze spatial information that can be taken from or added to maps. Using our measurements from the field, we could layer our archaeological roads (and other types of archaeological finds) atop various types of base maps. Throughout our field school, we had the opportunity to study unique historic maps of the Perthshire region dating as far back as the 1500s. Each map along the timeline was a snapshot of the events and progress in the region. The military survey map that quickly became important was William Roy’s Great Map. Roy was commissioned to create a map of Scotland after the Jacobite rebellion had been snuffed out at Culloden in 1776, the last battle on British soil. Roy’s map, initially to be used in the event of another uprising that never was, became the most accurately detailed depiction of Scotland during its time. This led to a map that paid particular attention to settlements, land use and topography, perfect for our historical archaeology studies, and could easily serve as a base map in QGIS.

During this field school, we learned that a pile of rocks was much more than a pile of rocks. Often called cairns, we sought to understand these man-made stacks of stones in the context of our project’s research basis. So, after uncovering one just uphill of Wade’s Military road in Faskally Forest, we recorded, photographed, and measured it. Later, we were able to see it on our maps created in QGIS. Still, the mystery of the cairn lay in front of us.

Rocks are a puzzle, but archaeologists and geologists like puzzles. After all, the information we need is usually right under our noses. Take Mount Everest, Earth’s highest mountain above sea level at over 8km. Its geology is varied, but its summit is shallow marine limestone. This does not mean that the mountain was once under an ocean. Mount Everest was the product of massive collisions between tectonic plates—the uplifting, faulting, and thrusting of sediments deposited in different environments. The cairn found in Faskally Forest was downslope of a cobbly railway, yet that one fact does not mean the rocks were used in either the production of the rail or its tailings. Perhaps the cairn was the product of the military road itself, whether a forgotten pile of stones to be used, or stones that were purposefully left unused. Both archaeologists, geologists and GIS specialists must use critical thinking to unravel these mysteries of time.

Archaeology unravels past events using geography, linguistics, sociology, culture and geology, so archaeological studies are usually chock-full of spatial data, that GIS can handle. Not only is its accuracy dependable, but it allowed us as students to visualize what we discovered during our fieldwork in an understandable way. With our background research, fieldwork, and GIS map making, we came full circle in a matter of weeks while surrounded by professional archaeologists to aid our study. Using GIS changed how we both acquired and viewed our data collection from the field. Additionally, we were afforded breathtaking sites like the Queen's View in Pitlochry, Wade’s Bridge in Aberfeldy, and the Schiehallion Munro of the Breadalbane region.

If our final goal as interdisciplinary scientists is to bring the past into the present, programs like GIS allow us to organize our thoughts, findings, and theories in a systematic, approachable way. It might be that each person is born into the top left corner of their own map, and as they live and experience, pen in the rest. Some maps are larger than others, and they all read uniquely, but each is important. Every archaeological find is a piece of someone’s map, or maybe, if we are lucky, many maps. We can stack the sheets and view a people’s history in three dimensions. It’s a way for us to read history, understand Earth’s unsparing timeline, and say we were here. Through maps, we codify our existence. As archaeologists, we write until the ink ends.