Assessment of RTK Quadcopter and Structure-from-Motion Photogrammetry for Fine-Scale Monitoring of Coastal Topographic Complexity

Advances in image-based remote sensing using unmanned aerial vehicles (UAV) and structure-from-motion (SfM) photogrammetry continue to improve our ability monitor complex landforms over representative spatial temporal scales. As with other water-worked environments, coastal sediments respond shaping processes through the formation of multi-scale topographic roughness. Although this complexity can be an important marker hydrodynamic forces sediment transport, it is seldom characterized typical beach surveys due environmental technical constraints. In study, we explore feasibility SfM augmented RTK quadcopter for monitoring at beach-scale a macrotidal environment. The method had resolution time constraints realistic representation topo-morphological features from submeter dimensions survey completion two hours around low tide fully cover intertidal zone. Different tests were performed field sites varied morphologies assess photogrammetric performance eventual means optimization. Our results show that, precise image positioning, addition single ground control point (GCP) enabled global precision (RMSE) equivalent that traditional GCP-based numerous well-distributed GCPs. optimal model quality minimized vertical bias random errors was achieved 5 GCPs, two-fold reduction RMSE. tie detection found on measurement quality, best obtained images their original scale. Using these findings designing efficient effective workflow large