Producing Digital Photogrammetric Products From Data Acquired Using Kinematic Gnss Methods
Producing Digital Photogrammetric Products From Data Acquired Using Kinematic Gnss Methods

Summary/Abstract: To determine the volume of material in a quarry and generate photogrammetric products, the DJI Phantom 4 RTK drone was used to capture 146 images, and a UniStrong G970 II GNSS receiver was used to determine the control points. For generating the orthophotoplan, the digital terrain model, and for volume determination, Pix4Dmapper software was used. During processing, interruptions were observed in the point cloud due to the shadow of the conveyor belt above the material and the camera's field of view (FOV), which caused insufficient data collection, leading to underexposed and obstructed areas. Due to these gaps, the volume determination is incorrect, as the software calculates the volume through the break in the point cloud, from the material to the height of the conveyor belt, resulting in a volume of 3211.84 m³ ± 20.12 m³. To compensate for this error, an additional volume of 93.45 ± 0.62 m³ was determined, representing the excess volume. Thus, the final volume, considering the difference between the two volumes, is 3118.39 m³ ± 19.5 m³. After introducing the control points (GCPs - Ground Control Points), their optimization was carried out by repositioning them correctly. The correct position is represented by the marks on the ground made with red spray paint. The actual mark is made at the intersection of the two red lines in the point cloud. Seven control points were used, placed near and on the material, whose position was determined with the UniStrong G970 II GNSS receiver. Comparing georeferencing with and without control points, precision decreases when using GCPs, but the position and quality of the products are correct, and the photogrammetric products can be used in other fields as well. For a detailed visualization of the area where the flight was carried out, contour lines can be generated using additional settings during processing. For the material volume and the surrounding area, contour lines with an interval of 0.5 m were generated, providing a detailed visualization. This can be used to track the behavior of a material volume over time or, in general cases, to monitor areas prone to landslides.

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