<b>Topo-bathymetric datasets of the Bonggil-ri coast, Gyeongju, Korea, from UAV, single-beam and multibeam echosounder surveys</b>

Each survey combined three platforms covering complementary depth zones: UAV photogrammetry for the beach and backshore, a small-boat single-beam echosounder in 1–20 m water depth, and a ship-borne multibeam echosounder in 5–40 m water depth.</p><p dir="ltr">Files (CSV, UTF-8, comma-separated, header row x,y,z; single-beam files also carry date, time_kst and line):<br>- Bonggil_2020_spring_SB.csv / Bonggil_2020_autumn_SB.csv: quality-controlled single-beam soundings (146,988 and 246,827 points)<br>- Bonggil_2020_spring_MB_1m.csv / Bonggil_2020_autumn_MB_1m.csv: multibeam 1 m grids (5,080,104 and 3,052,102 nodes; 5.08 and 3.05 km²)<br>- Bonggil_2020_spring_UAV_1m.csv / Bonggil_2020_autumn_UAV_1m.csv: UAV DSM 1 m grids with water areas masked (160,606 and 263,130 nodes)</p><p dir="ltr"><br>Coordinate reference: horizontal WGS 84 / UTM zone 52N (EPSG:32652), metres; vertical Pohang chart datum (DL) for all platforms, z positive upward and negative below the datum.

Soundings were reduced with 1 min tide records from the Pohang tide station.</p>