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High-Tech Drones Give Archaeologists a Bird's-Eye View of the Past

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Maybe all Indiana Jones needed was a good hat and a whip, but if he'd seen what archaeologists are using these days, even he might be jealous. From drones that perform high-fidelity 3-D scans to apps that automatically scour satellite data for undiscovered sites, the past has never looked more futuristic.

"Sites are disappearing all over the world due to looting, urban sprawl, warfare and other threats," said Steve Wernke, an archaeologist and associate professor of anthropology at Vanderbilt University. It's important, he said, to document them fully as soon as possible, because we only get one chance. Using unmanned aerial vehicles and advanced imaging techniques — two things Wernke is an early adopter of — makes a huge difference.

"It really provides better data, more precise data, more accurate data, and much faster. It's really an amazing thing to witness," he said.

Wernke works in Peru, where he and others are busily documenting ancient structures like Qhapaq Nan, the Incan "royal highway" that was recently awarded World Heritage Site status. What better tool to collect data on these miles of half-buried roads than an eagle-eyed UAV?

3D model of the planned colonial town of Mawchu Llacta in highland Peru, reconstructed from 241 aerial photos.
3D model of the planned colonial town of Mawchu Llacta in highland Peru, reconstructed from 241 aerial photos.Steve Wernke / Vanderbilt University

The drone is equipped with an ordinary camera, pointed down and set to take a picture every half a second. The thousands of overlapping pictures of the landscape are crunched by what's called a photogrammetry application. The result: highly detailed, accurate representations of the area like the one above.

Smaller 3-D capture systems can be suspended (or hover) over excavations, recording the dig layer by layer and noting the precise position and dimensions of every stone, pottery fragment and arrowhead. It's less work for the grad students, who can be set on more important tasks (like piloting drones).

"I imagine in the future archaeologists won't have just one of these things, but have a sort of quiver of drones," Wernke predicted, "from large-scale survey ones to lower-altitude stuff, the quad-rotors, to site-specific ones."

Vanderbilt University's drone takes flight. Fixed-wing craft like this one can't hover, but cover greater distances and have more stability in flight.
Vanderbilt University's drone takes flight. Fixed-wing craft like this one can't hover, but cover greater distances and have more stability in flight.Julie Adams / Vanderbilt University

At the very least there will be plenty of options as to what kind of gear to put on these drones. Jesse Casana of the University of Arkansas uses a highly original technique of capturing thermal imagery of the landscape, revealing features that were nearly invisible to the naked eye.

"People have been theorizing it was possible since the '70s," Casana explained to NBC News. "There was just no way to do it. You needed this liquid nitrogen-cooled camera flown overhead by a plane. Today, they're tiny, the size of a quarter."

Casana has also dabbled in research that automates the process of finding new sites: Feature-extraction software could scrub through thousands of aerial images looking for unusual patterns. It would have to be checked, of course. "There's a very important role for human analysis," he said.

In the thermal image (top), features can be distinguished that are far more difficult to see in the visible-light photo below.
In the thermal image (top), features can be distinguished that are far more difficult to see in the visible-light photo below.Jesse Casana / University of Arkansas

Drones are still problematic mechanically, though, and can be legally dubious in some places. In Cyprus, Casana said, "We were actually arrested and detained for a day while the police decided whether or not what we were doing was illegal." Still, he reported that all his colleagues either had or wanted UAVs for some purpose or another.

Saving the past

It's not just far-flung temples and ruins that are getting the high-tech archival treatment. CyArk is an organization whose mission is to record the world's most important and endangered places in extreme detail and make that data available to as many people as possible.

"We were started in response to the catastrophic loss of heritage sites and monuments," said Elizabeth Lee, CyArk's vice president.

CyArk uses a system called LiDAR, which bounces lasers off the surrounding area much the way radar uses radio waves. It produces a 3-D "point cloud," a dense collection of coordinates that can be woven together into a solid 3-D model.

A pair of images derived from Lidar instruments.
A pair of images derived from Lidar instruments.OpenTopography

Wernke enthuses about the technology: "In areas with a lot of tree cover, the LiDAR can tell the canopy from the ground, so you get what we call a bare earth model, just ground and all the architectural features you're looking for. It's been really, really transformative."

For example, he says, anthropologists used to think of the huge Mayan temples in the forest as religious centers, visited by far-flung families to pay their respects to the gods. But LiDar scans revealed evidence of a large and permanent population near the temples. "They were living all around there, in this huge agricultural society, managing and farming that forest — and we really only know that because of LiDAR," he said.

Geologists are getting into the fun, too, contributing and drawing from a growing database of high-resolution imagery of faults, slips and other tectonic features stored at OpenTopography.

A few of CyArk's tools for capturing images in the field.
A few of CyArk's tools for capturing images in the field.CyArk

With the ground LiDAR system getting the lay of the land and drones capturing finer details like frescoes and decorations, CyArk and its partners have already documented scores of sites, from Qing tombs in China, to famous cathedrals in Europe, to modern landmarks like the Washington Monument. One new project aims to record some endangered artifacts of the early industrial era: enormous cantilever cranes in Nagasaki, Japan.

"The data we're capturing is measurable and accurate, and can be used in ongoing restoration and preservation efforts onsite," explained Lee. And the hundreds of terabytes of data aren't just being used by academics. This kind of rich data is useful in lesson plans for kids who have grown up with 3-D games like Minecraft, who learn by interacting and exploring. You can get a taste of the captures with this online viewer.

LiDAR is great, but it's also expensive and bulky. It's shrinking in size and price, but both Wernke and Lee were excited about something smaller still: Google's Project Tango, a phone-like device packed with sensors that can record every detail of its movement, the room it's in, and the items in it.

"If Google is trying to put these sensors in every phone, how can we use that to capture the environment, use that capability?" wondered Lee. "The democratization of the technology has been really exciting for us."

Bird's eye view of a 3-D model created by moving a Project Tango device around a room.
Bird's eye view of a 3-D model created by moving a Project Tango device around a room.Google / YouTube

Wernke sees it as a huge cost and labor savings. "In archaeology we work with really small budgets, and these laser scanners are like $40,000," he lamented. "If we could just have our students whip out their phones..."

But what happens when all that data is unleashed? Wernke is worried that the infrastructure won't be able to keep up with the tools — although companies like Google have shown they're willing to help host and administrate huge amounts of data like the Cancer Genome Atlas. CyArk has already had to shift its focus from capture (which it still does, but through partners) to archival and making the data widely available.

Access to this data, Lee pointed out, seems to be the next big problem to solve — but with broadband, rich media in our browsers and devices, and near-unlimited cloud storage, we may be well on our way already.

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