A large, fixed-wing drone recently hovered in Great Sand Dunes National Park & Preserve, uninterrupted by a law forbidding such flights in national parks.

And the group spearheading the flight? Officials with the Great Sand Dunes itself.

“It is definitely the best aerial imagery of the dunes to date,” said Andrew Valdez, a geologist at the park who worked on the project.

The footage captured from 400 feet above ground wasn’t created to attract Youtube views. Park officials want to better track the ecosystem to see how sand shifts over time and impacts the dunes’ height and depth.

The National Park Service banned unmanned aircraft above its parks in June 2014, but authorities at individual parks can request to use a drone for park purposes. The Great Sand Dunes test was among about a handful of legal drone outings last year at national parks in the region.

In the Great Sand Dunes flyover, which happened Oct. 19, the drone took high-resolution images of 1 square mile of the park centered around the Star Dune, which at 750 feet is the tallest dune in North America. The park teamed with UAS Colorado, a nonprofit created to spur commercial drone development, and two of its members: Black Swift Technologies, the Boulder firm that developed the SwiftTrainer drone, and Wohnrade Civil Engineers, a Broomfield mapping and technologies firm.

The goal? Scientific research, said Mary Wohnrade, president of Wohnrade Civil Engineers.

“The park monitors the dunes to see how much they shift. How high are the dunes? Is it higher in elevation than last year? It’s generally for in-house research,” Wohnrade said. “…The milestone project will give research staff at the park meaningful data for monitoring change detection within the dune field, and to quantify, visualize and interpret resources it is charged with protecting.”

Previously, the park relied on aerial photographs from the U.S. Geological Survey and measurements taken using handheld GPS units. By using drones with high-resolution, 24.1-megapixel cameras, the team got detailed photos and used orthomosaic imaging software to piece them together.

Weather conditions and hauling equipment over sand made the mapping quest a challenge, but the resulting accuracy was good, said Valdez.

“Both vertical and horizontal accuracies are well below par for us, as I mention in the white paper. The shadows, homogenous scene, and very few ground control points all had an impact on the precision,” Wohnrade said. “We have already developed methods for improving accuracy on the next data collection in 2017. We are also in the process of developing a new custom-built UAS platform (developed by Black Swift Technologies), with a payload that will include a LiDAR scanner and a 42.3-megapixel camera. This platform will be capable of providing very high quality geospatial data.”

The team launched and landed the drone outside the park, which didn’t require approval. But the flight did require permission of the Federal Aviation Administration, which regulates the air above national parks, said Steve Sorensen, aviation manager for the intermontane region of the National Parks Service. UAS Colorado did the legwork. It had previously worked with the FAA to turn 8,000 square miles in the San Luis Valley into a testing area for commercial drones.

“The early flights were more of a test than anything else, and any future flights will likely result in us gaining the appropriate NPS approvals to launch from within” the park, Sorensen said.

Of course, many drone pilots don’t follow park regulations, like the tourist in August 2014 who crashed a drone into Yellowstone National Park’s Grand Prismatic Spring. Drones are not allowed in national parks unless launched and landed outside the park.

“We’re still catching people flying them in the parks. A week ago Saturday, a park visitor from the Rocky Mountains called me. He was irate. ‘What’s up with you guys letting people fly drones in the park?’” Sorensen recalled. “I told him they weren’t supposed to be doing that. Most people are respectful.”

Sorensen said his office approves requests by park officials to allow internal use of drones. He approved seven or eight requests last year. At Devils Tower National Monument in Wyoming, a team used a drone to get close-up images of the geologic monolith so park officials could turn them into an interactive tool for people who are handicapped or otherwise cannot hike to the tower.

“People can see foot by foot what is at the top,” he said. “And in 10 years, they can do another one to see what erosion has occurred and how (Devil’s Tower) was affected.”

The agency also approved a drone system in Grand Canyon National Park to help employees assist visitors who have driven or fallen into the canyon. Rangers can assess someone’s condition and locate a rescue helicopter landing spot, if necessary, without climbing into the canyon themselves.

“It (the Grand Canyon) is the only one, and I’m not letting anyone start another one for a year until we have some lessons learned,” said Sorensen, whose job includes saying no to government officials who request drones for their departments. “Everybody wants one of these things.”