Using UAS for Efficient and Accurate Topographic Mapping
Client: McLucas & Associates (for Kennedy Creek Quarry)
Location: Shelton, Washington
When it comes to topographic mapping, unmanned aerial systems (UAS) are an efficient and inexpensive alternative to total station surveys or aerial surveys using aircraft.
The high cost of total station surveys or aerial surveys using aircraft can make some organizations think twice about maintaining up-to-date aerial maps. But UAS’s ability to map large areas efficiently and inexpensively, makes it a viable alternative. So, when a new Department of Natural Resources permitting requirement necessitated a quarry manager to have up-to-date topographic data for the site, he reached out to MFA for UAS services.
To capture the aerial data, we placed 12 aerial targets for ground control and measured accuracy using a Trimble Geoexplorer 7X unit capable of real-time precision of 0.5 inches (horizontal and vertical). We collected additional GPS check points for a vertical accuracy assessment.
The UAS data gathered was developed in to a high-resolution orthomosaic aerial map and a dense 3D point cloud that was used to interpolate a 3D site model. To help the client clearly see important details of the mining site, we made slight modifications to the topographic contours to remove trees, and structures to create a pseudo-digital terrain model for spatial analysis and grading scenarios.
We used UAS to survey the mining site—with its extreme elevation changes—in just in one 35-minute flight.
View the 3D site model of the quarry we created in the video, below.