UK: Woolpert was contracted by the Wyoming Department of Transportation ( WYDOT) to perform aerial mapping services to assess three landslide-prone areas along a 10-mile stretch of U.S. 26 in northwest Wyoming. The region is near the Shoshone National Forest boundary, east of Togwotee Pass and west of Dubois. The site is close to Yellowstone National Park and along the Continental Divide.
Geologic conditions have caused multiple landslides in this region over the past decade, with some areas showing up to a foot of geologic movement in that span. Woolpert was brought in to utilize the firm’s aircraft, its Leica TerrainMapper lidar sensor and its in-house acquisition services to deliver classified lidar data and aerial imagery, which WYDOT can use to evaluate, prioritize and mitigate possible landslide events.
“Multiple passes were made over these three areas to collect data that met or exceeded the requested 50 points per square meter,” Woolpert Project Manager Chris Raml said. “The extremely dense, raw and bare-earth point clouds that we produced enabled WYDOT’s Photogrammetry and Surveys Section to create well-defined digital terrain models (DTMs) and triangulated irregular network (TIN) models specific to the needs of the department.”
These models created a detailed baseline of valuable data that will be compared to models created through future acquisitions to determine the slide movement, volume and rate at which the earth is moving.
Raml said TerrainMapper’s integrated RCD30 camera simultaneously acquired high-definition, 3-inch ground sample distance imagery that was rectified and used to colorize the lidar point cloud.
WYDOT Photogrammetry and Surveys Engineer John Goyen said, “WYDOT performed an independent check and compared over 120 individual point cloud elevations from field collected points. The average elevation difference of 3.6 centimeters exceeded the requested 5-centimeter vertical accuracy.”
Tom Ruschkewicz, Woolpert Roads and Bridges geospatial practice leader, said advanced mapping data like this has become essential to multiple local, state and federal applications, including disaster resilience.
“With highly accurate, linear-mode lidar sensors like TerrainMapper and the custom data they produce, the demand for this versatile information continues to grow,” Ruschkewicz said. “We are excited to be able to support WYDOT with this project and to continue to apply new geospatial technologies to scenarios outside of traditional applications for our clients around the world.”