Who knew there were sand dunes in Colorado? Through a recent GIS mapping project, the preservation of sand dunes in the Rocky Mountain state is realized with the help of photogrammetry and drones at the Great Sand National Park and Preserve in south central Colorado. A collaboration of four organizations worked on the project to preserve the untouched beauty of this clandestine national treasure.
UAS Colorado has completed an innovative mapping project using UAS within the park to survey its environmental health. The project was a collaborative effort facilitated by UAS Colorado that also included Black Swift Technologies (BST), the US National Park Service (NPS) and Wohnrade Civil Engineers (WCE).
Many US states have organized state-wide UAS economic development agencies. North Dakota and Nevada are among the states pushing the envelope of remote vehicle technology within their borders. UAS Colorado is the official trade association for UAS in Colorado with a mandate of encouraging integration projects.
“The milestone project will give research staff at the Park meaningful data for monitoring change detection within the dunefield, and to quantify, visualize and interpret resources it is charged with protecting,” said Mary Wohnrade of Wohnrade Civil Engineers. “The research staff is very pleased with the results. It is definitely the best aerial imagery of the dunes to date! The project succeeded in illustrating the incredible capabilities of UAVs in science, engineering, and precision mapping.”
Working in conjunction with NPS park staff, the goal of this project was to develop precision mapping approaches using high-fidelity remote sensing to monitor change detection, measure dune height in the vicinity of the Star Dune, and to visualize and document the natural resources that the NPS is responsible for protecting. Star Dune is part of the 30 square mile field of this remote desert anomaly at the highpoint of the Crestone Mountains.
“Black Swift Technologies was excited to be a part of this landmark effort, and were excited to face the challenges of the project with our industry leading SwiftTrainer aircraft. This required operations at altitudes of up to 9000′ altitude MSL and gathering data over an area of interest more than 5 miles from the launch and recovery site, something that exceeds the operational limits of most small drones.”
For this project, Wohnrade Civil Engineers became the first FAA-licensed service provider to use a UAS to successfully map a one (1) square mile area of the Great Sand Dunes National Park & Preserve. The UAS data collection was performed on October 19, 2016 using the SwiftTrainer fixed-wing drone developed by Black Swift Technologies. The resulting terrain data set will be compared to a 2011 airborne LiDAR acquisition prepared by the United States Geological Survey (USGS).
The Great Sand Dunes National Park is a unique environment, making aerial data collection technically challenging. Several challenges were posed to the UAS team for all phases of the mission. A combined total of seven surveyed ground control points (GCPs) and check points (CPs) were set by a two man crew from Wohnrade Civil Engineers on October 18, 2016.
The Area Of Interest (AOI) was inaccessible by vehicle requiring travel by foot, which consequently meant the establishment of the seven GCPs and collection of their individual GPS x,y and z coordinates took approximately 8 hours.
Flight planning was similarly difficult given one condition of the NPS Scientific Research and Collecting Permit was the UAS launch and landing site be located outside of the Great Sand Dunes National Park boundary. Another difficulty arose due to the mapping AOI contained elevation variations of up to 750ft (229m). This required the aircraft to track steep flight angles to maintain a uniform ground sample distance.
In spite of the long transit to the 1-square mile AOI, the mapping team was able to finish the mission in two flights, collecting 1,755 images in only 2 hours and 30 minutes on site. The raw images were geo-tagged using flight data from the UAS and fed through a photogrammetric process to generate the required data products.
First, each image was rectified and combined to produce an orthomosaic map over the AOI, providing an aerial view of the features of each dune at nearly 1 inch (3cm) per pixel resolution. Second, overlapping features across images were used to derive a three-dimensional point cloud of the AOI topography. This data set is extremely comprehensive and includes over 145 million points, or close to one point for every 1.5 square inches on the ground.
Black Swift has designed aircraft and avionics for several remote sensing projects around the world including routine observations of volcanic plumes, soil moisture measurements and mapping flights near the summit of Mt Evans (14,265′). Last summer the company participated in a “fly-off” between several industry leading companies, an event sponsored by CH2M.
About UAS Colorado
UAS Colorado is a non-profit business league, committed to promoting and improving the commercial drone industry in Colorado, particularly supporting the safe integration and use of unmanned aircraft systems throughout the state for the benefit of the public.
About Black Swift Technologies
Black Swift Technologies is an engineering firm based in Boulder, Colorado specializing in the development of next generation small unmanned aircraft platforms and technologies.
About Wohnrade Civil Engineers
Wohnrade Civil Engineers of Broomfield, Colorado, provides a broad range of professional engineering services to public and private sector clients in Colorado, Illinois, Wisconsin, and Nebraska since 2002.