XÂY DỰNG SƠ ĐỒ ĐỘ SÂU VÙNG BIỂN VEN BỜ PHÍA NAM VỊNH NHA TRANG DỰA TRÊN PHƯƠNG PHÁP NỘI SUY NGHỊCH ĐẢO KHOẢNG CÁCH CÓ TRỌNG SỐ

CONSTRUCTING THE BATHYMETRIC MAP OF THE SOUTHERN COASTAL AREA OF NHA TRANG BAY BASED ON THE WEIGHTED INVERSE DISTANCE INTERPOLATION METHOD The bathymetric maps of shallow coastal areas, islands, and sandbanks are considered useful sources of information and serve as a basis for creating maritime safety charts and managing the environmental resources of water bodies. This study uses open-source software (R and QGIS) to evaluate the influence of different ratios between training and validation datasets, while also optimizing the power parameter (p) and the number of neighboring sample points (n) in the IDW interpolation method. The goal is to create a bathymetric map for the southern coastal area of Nha Trang Bay using data from GEBCO_2023 and field survey depth measurements. The results show that increasing the number of training data points and optimizing the parameters p and n reduces the error of the IDW interpolation algorithm. This study indicates that the bathymetry dataset data80 (with a ratio of 80% training and 20% validation), a power parameter of 2, and a number of neighboring sample points of 4 are considered the optimal ratio and parameters, and are used to create a bathymetric map with a resolution of 3 m x 3 m in the study area. The RMSE between the measured and predicted bathymetry data from the IDW interpolation algorithm is 0.597 m. In the southern water area of Nha Trang Bay, the spatial distribution of bathymetry tends to increase from the shore outward.