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Pix4D: Processing UAS Data

INTRODUCTION Unmanned aerial surveillance photography is an efficient, affordable method in gathering data for small to medium-sized projects for a wide variety of uses. These platforms have a high-degree of customization with various attachments to achieve their goals. Besides controlling the flight and collecting data, the data processing can be an intensive process that involves careful attention to produce accurate results. Pix4D mapper is the most common software in UAS point cloud processing and is demonstrated in this report. Data was collected in the previous report UAS Platforms and GPS Units for Ground Control at the Litchfield mine located southwest of Eau Claire, WI. METHODS Before processing UAS data in Pix4D, a basic understanding of the software and goal-specific requirements should be obtained. To produce a 3D model, the UAS collects overlapping images and calculates elevation based on these images. The distance of overlap should vary according to th...

UAS Platforms and GPS Units for Ground Control

Introduction Hands-on field work with various UAS craft and GPS devices for ground control points were conducted at the Litchfield Mine located in Eau Claire, WI (see Figure 1). Figure 1: The Litchfield Mine located on the Southwest side of Eau Claire, WI Methods Survey Ground Control Points Ground control points (GCPs) are used to geo-reference the data collected by UAS technology to improve accuracy and be represented on a GIS. They connect data collection to real-world coordinates. The method we used was to fully cover the area of interest with variability in elevation, avoiding clustering GCPs, and placing them in a triangular pattern to best record accuracy. We used markers to demarcate our GCPs shown in Figure 2. Figure 2: an AeroPoint GPS marker used as the 6/16 GCPs taken After all GCPs were placed, a variety of equipment was used to record the coordinates of these markers including the Trimble R2, Septentrio, Altus NR2, Topcon HiPer, Bad Elf GPS...