A Tale of Two Drones
Two Illinois researchers use drone technology to answer fascinating questions about the past and future of our state
By Colin Worden, Organizational Psychology '20
The University of Illinois, at times, can seem like a series of separate kingdoms rather than the sprawling intellectual ecosystem it is. Particularly when we look at research on campus, these differences can be stark. Take, for example, these two actual research projects: an archaeological survey and excavation in the town of Chester, Illinois; and the tracking of shoreline erosion on Lake Michigan. These projects seem worlds apart and yet there is a link between them. That connection, standing just over a foot across and weighing slightly over 3lbs is a drone, and it is a technology that is greatly assisting research here for multiple departments. I interviewed both John Lambert at the Illinois State Archaeological Survey (ISAS) and Dr. Ethan Theuerkauf at the Illinois State Geological Survey (ISGS) to get the scoop on how Unmanned Aerial Vehicles (UAVs) aid in their research.
Mapping the Archaeological Landscape
"The drone is very exciting because it lets us see archaeological landscapes and sites in ways that we never could before,” says Spatial Analyst John Lambert at the Illinois State Archaeological Survey. ISAS purchased a DJI Phantom Four Pro drone last year and it has been a great complement to the existing work they do. Previously, if an archaeologist wanted to get a bird’s eye view of a site to survey for features, they either had to create or find a vantage point, use existing imagery, or get an airplane to fly overhead. “The drone is much easier,” says John, “we can get really nice, high-quality shots of excavations from 50 or 100 feet up, and you just can’t do that with a handheld camera.” These site surveys are important because they enable archaeologists like John to identify sites that may be impacted by development. When development may affect a site, archaeologists excavate the site prior to construction and carefully document and analyze any archaeoloigcal features or articfacts discovered.
"It's fascinating to uncover what people were doing in the past," John says, "holding an object in your hand that no one else has touched for thousands of years is just very cool. Branching out from that, we get to bring innovative analysis and theory together to answer some real questions about the past that still matter today." The drone technology helps speed this process along and does it better, which means these important questions get answered faster.
Aside from site surveys, the main use of the drone for ISAS is photogrammetry, which is the process of measuring 3D surfaces via overlapping photographs. This can create a virtual model of the site, known as a Digital Elevation Model (DEM). This DEM is useful for putting the site in the context of the landscape while helping archaeologists “look for archaeological features we didn’t know were there,” as John explains it. “Some features like Earthen burial mounds can be really subtle and only come up above the ground surface 20 or 30 centimeters. But the DEM from the drone can pick that up and help us see features that wouldn't be noticeable from the ground.” For ISAS, much of their work is with the Illinois Department of Transportation, so the elevation models they make help plan for the future of Illinois roadways. Another way to create a digital elevation model is with airborne LiDAR, or light radar, which makes measurements using lasers. LiDAR flights are much more expensive than drone-based photogrammetry, and they have to be scheduled months in advance. These cost-prohibitive and time-consuming drawbacks are why the drone is a great resource for doing the job quicker, cheaper, and with higher resolution.
While the drone is handy, it has limits. Since the drone is photography-based and not laser-based like LiDAR, vegetation poses a challenge: the drone will measure the top of the vegetation instead of the ground, which can lead to inaccurate results. Even if the measurements are accurate, what the DEM would indicate as a burial mound can actually turn out to be just a modern mound of dirt someone made. It’s for that reason that archaeologists will undergo a process they call ground-truthing. Ground-truthing, explains John, is the act of going to the actual site to verify what has been seen in the sky is accurate, and potential archaeological features were not caused by modern construction or activity.
For example, they may verify that what the drone indicates is a burial mound is actually a burial mound (and not a modern mound of dirt). Working on the ground is what most people probably think of when they imagine an archaeologist, and even with new technology, this is still true. John did stress that while the drone is a good tool, “it is always in addition to the things we’re doing, it’s not a replacement.” They still go on location to truth their data, and the drone can’t excavate a site. That being said, while it can’t do the entire job, the drone has been a wonderful asset to the ISAS team. It has considerably sped up their access to high quality, aerial data which aids their mission to understand the past better.
Exploring the Great Lakes Coasts
Further up, in Northern Illinois and beyond, different research is occurring. “I look at modern coastal processes, so I see things changing in front of my eyes. What I get really excited about is understanding why that’s happening,” says Dr. Ethan Theuerkauf, a Coastal Geologist at the Illinois State Geological Survey (ISGS) and the principal investigator for the Great Lakes Coastal Geology Research Group. Their group also uses UAV to assist in research, albeit for a different purpose. Ethan and his lab are trying to answer the question: How do beaches, dunes, and other features along the Lake Michigan Coast respond to changes caused by natural events like storms and lake level rise? As Ethan explains, “a lot of the same things you hear about nationally or globally like sea-level rise and hurricanes occur here in the form of lake level rise and storms, but they don’t get the same kind of press.” To look for a change in these lakes, it has to be mapped through time. While they can use GPS or LiDAR to do these measurements, these technologies are typically used on a really big scale. For this reason, the drone offers a small scale approach that is more conducive to doing this kind of work. Just like the workers at ISAS, they use photogrammetry to map the landscape and the drone is considerably less time consuming compared to other options like ground-based LiDAR. The drone will run a pre-planned route to ensure consistency, but in a surprisingly human moment for an interview about mechanical drones, Ethan confesses: “I’m a control freak so I’ll always land it manually.”
While ISAS limits with the drone are vegetation and uneven terrain, Ethan runs into his own set of problems in the coastal areas. In fact, just one hour before our interview, he had been informed that a state park in Michigan where they were set to fly the drone had banned all drones - even ones there for research. Drones are a relatively new craze and the laws surrounding them are still being worked out. Unfortunately for Ethan and his research, he gets treated the same way any hobbyist drone pilot would. While he’s confident he can work with the park and get a permit, it’s just an extra step needed versus one of the other mapping techniques. The other concern? “They sometimes crash. Three weeks ago we lost radio contact with one [drone] and it nose-dived into Lake Michigan,” Ethan says. “They wear out and you can lose your equipment and data because it fell out of the sky.” The most fun challenge, however, is just people interested in drones. They’ll come up and ask Ethan questions about the drone and he’ll get to explain his research in the meantime. This is a challenge when he is trying to get work done, but he is glad to see people passionate about the coast. When compared to the other challenges drones pose for him, this one ranks very low. The joy of seeing that passion in others extends to his lab group. “I really like working with students and showing them how to do all this work and getting them fired up about coastal change,” Ethan says, “It’s fun and rewarding. The best part about doing research is getting to teach how to do research.”
After asking Ethan why he thought drones aren’t used more in research, he explained that it’s still a new technology. That being said, their use has grown in the last five years and they are being incorporated into more research in coastal environments. In the Great Lakes specifically, drones aren’t used much since he is one of the few researchers doing this kind of work, as compared to better-studied coasts like the Gulf, East, or West coast. This kind of work is still important here. Reflecting on why he enjoys the research he does, Ethan explains that “coasts are really important for the economy, ecology, and just people in general. The work I do to understand the coasts really does help manage the landscape.” For ISGS, the drone is useful and helps them map that change more affordably and quickly than other methods. Well, it’s quicker as long as the data doesn’t fall to the bottom of lake Michigan, that is.
Combining everything together, it looks like UAV technology has been a wonderful asset for collecting data in our changing world. Whether it’s uncovering the mysteries of the past or trying to protect our coastlines for the generations of tomorrow, drones are helping us do both better than ever. While research at Illinois is abundant and diverse, some commonalities link different groups together. This is especially true as it pertains to an emerging technology like drones.
Special thanks to John Lambert and Dr. Ethan Theuerkauf for lending their time and expertise to make this piece possible. If you have an interest in learning more about drones, CITL holds workshops on occasion. If you’re interested in piloting a drone, you can reach out to the UIUC Drone Club or the Illini Drone Racing Club.