Drones are rapidly becoming the tool of choice for Stockpile Measurement and Volumetric Analysis, producing results that are highly accurate, more timely and less expensive.
Drone collected imaging data has generated measurements within mere centimeters of difference from traditional photogrammetry. In a study by Pix4D, a senseFly eBee was equipped with a standard 16-megapixel Canon and deployed over several gravel stockpile sites. The same sites were further surveyed using expensive, cutting-edge Riegel VZ400 laser scanner and RTK GNSS. Even across sites with varying vegetation, geological composition, and human development, the mean variation between volumetric results was only 3 centimeters. Loose and fill materials volumes could similarly be calculated with groundbreaking precision and ease.
The variation not only complied with practical surveyor requirements, but was well within the margin of statistical error. Operating with industrial-grade cameras and at lower flight attitudes would further cut down on these almost imperceptible differences.
While the objective was to ascertain stockpile volumes, UAV surveying provided highly detailed digital surface models (DSMs) and geo-referenced orthomosaics at no additional cost. The cross-integration with existing GIS/CAD software also proved a treat -- leading to a smooth, fully automated workflow. Most importantly, utilizing UAVs reduced time and cost by eliminating the need for cumbersome substations and more expensive equipment.
While drone surveying was developed primarily for construction and engineering purposes, the technology has been pushed into other fields such as precision agriculture. Biomass volume estimation in particular has proven highly effective in assessing crop yield and health. Growth can be monitored on a weekly, plot-by-plot basis alongside factors such as plant genetics and field treatments. Agriculture professionals will certainly find UAVs tremendously beneficial as this new index raises efficiency in labor and resource allocation. Other industries will no doubt reach the same conclusion as UAV manufacturers and developers continue to push the envelope of volumetric analysis.