Eye in the sky: The 100-metre tall archaeologist with x-ray vision
December 11, 2017
December 11, 2017
Head into the field and learn how Stantec is using archaeology, remote sensing, and drones to see below the surface from the sky
Imagine flying high in the sky, looking down, and spotting objects underground that others could only see if they dug in the right spot. You’ve got a superpower—something like x-ray vision—and it’s changing the way you look at the world. You can see leaking pipelines, broken cables, ruptured infrastructure, not to mention mysterious traces left behind by ancient civilizations. Imagine how you can help the environment, enable industry, and re-write history with this incredible ability.
Archaeologist Butch Amundson (Saskatoon, SK) and his talented colleagues have done more than imagine this possibility. They’ve brought this superpower to life.
“By putting an unmanned aerial system (UAS)—or drone—in the air with a camera and special filters, we created a 100-metre tall archaeologist with x-ray vision,” said Butch. “This really is a risk assessment tool. Not just for archaeology, but for oil and gas, the mining industry, anybody with buried infrastructure.”
So how did this all get started? With the lofty idea of combining some traditional archaeological methods with some unexpected technologies, Butch connected with our UAS operations manager Kevin Grover (Edmonton, AB) to take a drone to an archaeological landscape near the Alberta-Saskatchewan border. They added multi-spectral photogrammetry (a type of aerial photography) to the mix—in this case a near-infrared camera and thermal sensor—to see if they spotted anything different than they did with their traditional boots-on-the-ground archaeological survey.
Compared to a traditional ground-based survey on the site, one-third of the archaeological features identified—like tipi tent rings and stone structures from an ancient community—were found by both the ground team and the air team, one-third of the community’s remaining features could only be seen on the ground, and the remaining one-third of the features could only be seen from the sky (drones are better at finding tipi rings and non-linear structures).
“We found that to create a thorough archaeological record of a landscape, both techniques are required,” said Butch. “Drones are not going to replace boots on the ground.”
Although they had already made a discovery, the dynamic duo of Butch and Kevin still had more ideas to explore. They brought in Grant Wiseman (Winnipeg, MB), a geomatics remote sensing specialist, who applied a normalized differentiated vegetative index (NDVI) to the results. The NDVI measures the growth of or stress on vegetation compared to its surroundings.
So, what happened when the NDVI was applied to the photogrammetric results? The team found an archaeological feature not visible to the naked eye. An unusual “halo” around a tipi ring, to be specific.
“With the NDVI, this project went from being a standard comparison of two methods—eye in the sky versus boots on the ground—to a project where we discovered something out of the blue that we didn’t know existed from the application of inductive research,” says Butch.
“We discovered an archaeological feature that nobody knew about because it was invisible to the human eye. That’s a game-changer to archaeologists. We just started to see things we didn’t know existed”
The team still wasn’t done. Butch wanted to know how to find those invisible features. The answer lies in object-based image analysis (OBIA)—essentially training a computer to use photogrammetry and NDVI data to automatically locate hidden objects.
“What we’ve done is train a computer to be an archaeologist. In other words, the computer automatically finds the archaeological features invisible to humans,” Butch explains.
For Grant, working on this innovative project with Butch and Kevin has been a master class in knowledge-sharing. He learns about UASs and archaeology while his teammates learn about remote sensing. Grant says he often confers with Kevin over the use of drone or high resolution satellite imagery primarily on infrastructure project. Sharing project findings with Butch and seeing his enthusiasm has been “sheer joy.”
“This project combines three disciplines—archaeology, UAS, and OBIA—which have historically not worked together. We’re generating new knowledge that would otherwise go undetected,” says Grant.
He believes the results of this research are tremendous for any client looking to alter the earth’s surface in areas where there may have been previous settlements.
Margaret Kennedy, Associate Professor of archaeology at the University of Saskatchewan, is a longtime academic peer of Butch. She believes this project is important for the field of archaeology.
“I think it will have very big implications for how remote sensing is applied in archaeology,” says Margaret, who, along with colleague Dr. Brian Reeves, conducted the original fieldwork on which Butch based his research. “I applaud Stantec for supporting this vital archaeological research and Butch’s innovative ideas.”
Margaret adds, “The use of UASs and multiple photographic platforms has exploded in archaeology and the resulting imagery has been spectacular. Now is the time to fine-tune the utilization of UASs and Butch’s research will have very practical application as to how archaeological fieldwork could be re-envisioned, or enhanced, in the future with the careful addition of photogrammetric techniques.”
Margaret and Butch stress that these new techniques won’t keep archaeologists away from the field. Rather, it’s another tool in the box to help professionals do their best work.
Butch sees applications for the photogrammetric NDVI and OBIA method outside of the archaeology field. Whether using high-resolution drone or satellite imagery, this method will help clients understand what’s happening underground.
“Archaeology is the tiniest tip of the iceberg,” says Butch. “We can apply this method to most of the disciplines here at Stantec. We can have a technological edge by solving some of the questions our clients have at the start of a project. Ultimately, I’d like to use off-the-shelf imagery and answer questions for our clients same-day.”
Butch is moving forward with research with support from Stantec’s Greenlight Program, a $2 million annual fund that financially supports employees’ good ideas. Butch received Greenlight funding for his original drone and filter research and has since received a second grant to ground-truth his photogrammetry research.
Although he sees broad potential for this method, the gregarious archaeologist still has roots in the field. “Now we can help our clients avoid accidentally hitting archaeological sites that we didn’t know existed,” he said. “We’re seeing things that are buried underground rather than stuff that we can only see at the surface. This is the most fun I’ve ever had as an archaeologist.”
There’s nothing quite like the power of a 100-metre tall archaeologist with x-ray vision.
This article is part of an ongoing series focusing on the value Stantec’s Greenlight program brings to clients, communities, and employees. Through Greenlight, Stantec invests up to $2 million annually to fund employee ideas that benefit our clients, community, and Company. Greenlight is part of our Creativity & Innovation Program, which celebrates and encourages creativity and innovation at work and in our work. Check back soon for another story in our Greenlight series.