High-Precision 1:1,000 Topographic Mapping Using Drone Imagery and PPK Techniques in Flight-Restricted Areas

This study investigates the feasibility of producing high-precision 1:1,000 digital topographic maps using drone imagery in Dong-myeon, Yanggu-gun, a flight-restricted area. The study area covers approximately 1 km × 1 km, with elevations ranging from 273.5 m to 432.5 m and a maximum relief of 159 m. Image acquisition was conducted using a Wingtra One GenⅡ unmanned aerial vehicle, while GCPs (Ground Control Points) were surveyed using the Network RTK (Real-Time Kinematic) method. To reduce reliance on ground control points in restricted-access environments, the PPK (Post-Processed Kinematic) technique was applied, and positional accuracy was evaluated using four GCP configurations consisting of 9, 7, 5, and 3 points. The experimental results showed that all cases met the accuracy requirements for 1:1,000 digital topographic map production, namely horizontal and vertical position RMSE values of less than 0.3 m and maximum errors of less than 0.6 m. In addition, the feasibility of generating contour lines from point clouds derived through image matching was examined. The analysis revealed that accuracy requirements were satisfied in non-forested areas, whereas significant errors occurred in densely forested regions. These findings highlight inherent limitations in forested environments, where supplementary data such as forest standard maps and additional sensors may be required to ensure consistent contour quality. Overall, the results demonstrate both the technical feasibility and limitations of drone- and PPK-based topographic mapping in flight-restricted areas, providing a foundation for future institutional and regulatory developments related to drone-based public surveying.