Review of Bathymetric Surveying and Mapping Techniques

Bathymetric information is essential for navigation safety, coastal engineering, marine habitat mapping, seafloor characterization, and climate‑related studies. However, de-spite major international efforts, to date, only 27.3% of the world’s ocean floor has been mapped in accordance with modern hydrographic standards, underscoring the need for more comprehensive and higher‑resolution seafloor data. This review provides an integrated assessment of the main techniques used for bathymetric data acquisition, examining their physical principles, operational constraints, data‑processing work-flows, and accuracy drivers. The analysis covers acoustic methods, including sin-gle‑beam, multibeam, and interferometric sonars, optical approaches based on elec-tromagnetic radiation, airborne LiDAR bathymetry, radar altimetry, and wave‑spectrum‑based techniques, together with a set of unconventional and emerging methods that offer additional flexibility in challenging or data‑poor environments. For each category, the review discusses achievable spatial and vertical resolution, envi-ronmental limitations, platform‑dependent constraints, and the influence of water properties on measurement reliability. Attention is given to data‑processing steps such as sound‑speed correction, motion compensation, filtering, and interpolation, which strongly affect the quality of the final bathymetric product. A comparative synthesis highlights that no single technique is generally optimal: acoustic systems remain the most accurate and versatile, while optical and LiDAR methods excel in shallow, clear waters. The analysis indicates that synergistic use of complementary techniques, leveraging the strengths of each sensing principle, is es-sential to produce bathymetric datasets tailored to the specific requirements of diverse mapping applications.