High-Resolution Coastal Topographic Model Using UAV Based Multi Georeferencing Method for Enhancing Sustainable and Resilient Coastal Zone Management

Coastal zones are dynamic and vulnerable environments that require high-resolution topographic data to support sustainable and resilient management. This study aims to develop a high-resolution coastal topographic model using UAV photogrammetry with a multi-georeferencing approach, comparing Ground Control Points (GCP), Post-Processed Kinematic (PPK), and a combined GCP–PPK method. The research was conducted in the Kenjeran coastal area near the Suramadu Bridge, Surabaya, Indonesia using UAV survey. UAV surveys were performed to generate orthomosaics and digital terrain models (DTMs). Each georeferencing method was applied independently to evaluate its influence on spatial accuracy. Accuracy assessment used twelve Independent Check Points (ICPs), with horizontal and vertical accuracy evaluated through Circular Error (CE) and Linear Error (LE). The results indicate that the GCP-based model achieved the highest accuracy, with LE and CE values of 0.149 m and 0.264 m, respectively, outperforming both the PPK and combined methods. While PPK offers greater operational efficiency by reducing field control requirements, GCP-based georeferencing remains the most reliable for centimeter-level coastal mapping. The combined method provides a balanced trade-off between accuracy and efficiency. This study supports SDGs 13 (Climate Action) and 14 (Life Below Water) by enhancing climate-resilient coastal management.