Measuring Stockpiles with Drones How Does Accuracy Compare with Traditional Measurement Methods?

Drones are poised to transform stockpile measurement methods over the next several years.

Capturing and processing stockpile images with a drone is quick, safe and significantly less expensive than traditional survey and measurement methods. But everyone wonders, “How Does Accuracy Compare with Traditional Measurement Methods?”

Although stockpile measurement has long proved essential across various industries (e.g. mining, aggregates, construction), implementation has been difficult due to expense and portability. Traditional LiDAR survey scanners cost thousands if not tens of thousands of dollars. Most are either terrestrial or mobile, which respectively necessitate tripod site setups and vehicles laden with bulky equipment. With the advent of commercial drones or UAVs however, stockpile measurements are expected to rise to new heights -- providing cutting-edge precision while reducing time, equipment, and personnel. Yet all things considered, just how accurate are drone-derived stockpile measurements?

In a Geoconnexion International Study published by leading UAV processing software developer Pix4D, several gravel and sand stockpiles were measured simultaneously by drone capture and terrestrial LiDAR scanning methods. Pix4D captured 212 still images by equipping fixed-wing senseFly eBee drones with 16MP Canon cameras, while scanning through Riegl VZ400s and two survey stations. Both methods utilized volumetric analysis by subtracting surfaces calculated in GIS/CAD software. Statistical analysis ultimately determined the mean deviation between the two methods to be around 3cm -- easily rivaling the best results theoretically considered achievable. Although marginally significant, the error could be further reduced by applying higher quality cameras and lower flight attitudes. While both methods produced similarly accurate results, drone capture provided the added value of digital surface models (DSMs) and geo-referenced, highly detailed orthomosaics.

The results of this study, among numerous other comparative studies, categorically concludes that stockpile measurement performed by drones is as accurate (and sometimes more accurate) than traditional lidar survey methods with the added benefits of improved safety, reduced labor, quicker processing and lower costs.

When operated safely and responsibly, drones consistently deliver stockpile measurements well within practical surveyor requirements. DroneView Technologies is a FAA-licensed aerial imaging, data analytics, and geospatial solutions company with cross-industry expertise. Feel free to contact DroneView Technologies for unparalleled services throughout the United States.