Depth bands are ecological, not evenly spaced — they mark the reef-building limit, the mesophotic floor and the shelf break. Vertical scale is non-linear: the top 60 m is shown at full scale and everything below is compressed, or a 7 km trench would flatten the reef to a sheet. Seafloor provenance: 78% of this frame comes from GMRT's high-resolution multibeam soundings; the rest is interpolated from a coarser background grid and is measurably smoother. The closer views sit largely on that fill — Rock Islands 18% surveyed, Ulong Channel 2% — so fine structure there is the model, not a survey. Depths are relative to approximately mean sea level with no tidal reduction, so the waterline on a shallow flat is datum-dependent.

Allen Coral Atlas, 10 m satellite-derived classification. Mapped to roughly 30 m depth — below that the class is unmapped, not absent.

Current is the ~25 km geostrophic field from altimetry — the regional set. It does not resolve tidal flow through a reef channel, which is the flow a diver feels and the flow that times a spawning aggregation.