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Camera-Equipped Autocopters Map Forest Treetops

Researchers are challenging ecologists to rethink the way they collect data by developing small unmanned copters that easily generate interactive, 3-D maps of any landscapes



Daniëlle Hoogendijk, ecosynth.org

Story originally published on Txchnologist

Trees don’t make work easy for the scientists who want to study them and the landscapes they create, since the leaves, fruits and flowers of a forest’s canopy generally stretch far above human reach. So, a team of researchers is turning to drones, programming these pilot-less flying machines to buzz over forests while snapping pictures. 

“I flip the switch on the controller and away it goes on its own,” says Jonathan Dandois, a doctoral candidate at the University of Maryland, Baltimore County, as he launched a drone over a patch of forest on campus on an overcast October day. “It will climb up to about 100 meters above and will continue on its route.”

The spiderlike machine carries a point-and-shoot camera aimed at the ground as it travels along a preprogrammed path defined by GPS coordinates. But Dandois and fellow researchers are trying to do more than just get a bird’s-eye view of the treetops. 

Dandois is working on Ecosynth, a suite of tools his team is developing with National Science Foundation funding. Their goal is to allow anyone from a professional ecologist to a citizen scientist to generate an interactive, three-dimensional map of any landscape. He says that a confluence of ever-cheaper drones — Dandois prefers the less ominous term autocopters — with more accessible and user-friendly 3-D mapping and visualization software has made this project possible. 

Insights from above

Dandois envisions the project doing more than making forest surveys easier. “It might inspire ecologists to rethink the ways they collect data,” He says.

This could potentially include developing algorithms to find particular features, such as flowers, in images collected from above.

In June, Dandois went to a Smithsonian Tropical Research Institute study site in Panamato test the system. Trees there are surveyed at regular intervals by people on the ground, so the information collected until now has been limited to things like trunk diameter that could easily be measured on foot, says Helene Muller-Landau, an ecologist with the institute. “But (these measurements) are not necessarily the most interesting or useful things you want to know.”

Ecologists’ other options, which include satellite data or aircraft-borne scans, have drawbacks. These can have low spatial resolution, are collected infrequently, or cost a lot, Muller-Landau says.

Muller-Landau is interested in year-to-year variation in the cycles by which different species of trees grow and shed their leaves, fruit and flower. Fluctuations in these cycles reflect trees’ responses to annual variability in climate, and hint at how they will fare in the face of long-term climate change. To document these cycles, she wants to gather images every week over the course of years, something not currently feasible. 

(A view of agricultural land in Costa Rica captured by a drone. Courtesy Jonathan Dandois, Ecosynth.org)

(A view of agricultural land in Costa Rica captured by a drone. Courtesy Jonathan Dandois, Ecosynth.org)

The Panamanian test run encountered a few issues: an autocopter crash and the realization that the images they collected needed to overlap more. However, the system proved largely successful, she says. Viewing the images in 3-D makes tree height, as well as gaps in the forest, leafless trees and fruits easier to identify.

“This technique is so new I think as people start to explore it, we will figure out a lot more things we can do with it,” she says. 

Maturing tech opens opportunities

Ecosynth’s approach became feasible when the cost of hobbyist-grade multi-rotator autonomous copters fell to about $5,000 around three years ago. At the same time, the 3-D reconstruction software necessary to compile all of the images was becoming easier to use. Ecosynth computer scientists are working to make the software more accessible by developing their own open-source 3-D mapping program. 

Scanning the Earth’s surface from above, a technique known as remote sensing, requires a great deal of technical sophistication. But Ecosynth intends to open this field to just about anyone. 

Because 3-D data often comes in prohibitively large files, engaging newcomers means making this information easy to visualize and access remotely, Dandois says. This is where Ecosynth’s social dimension comes in. Its collaborators are developing a system to transform the 3-D map into a virtual world users can access with nothing more than a standard Internet browser. In it, users can interact with each other in real time by, for example, highlighting trees and chatting. A demonstration is available on the Ecosynth website.   

Ultimately, making this system as accessible as possible means ditching the copters, since some training is necessary to use them, Dandois says.  

NSF funding is also supporting Ecosynth’s attempt to develop a system that allows users to collect images with a smartphone or tablet in lieu of a copter. This could allow a user to walk through a forest, a park or a backyard and collect images that could be employed to generate a virtual version of anyone’s ecosystem, he says. 

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