S-102 Bathymetric Surface

S-102 is the IHO S-100-based product specification for a high-resolution gridded bathymetric surface, delivering depth as a regular grid with per-node uncertainty rather than the discrete soundings and contours of an ENC. In ECDIS it supports dynamic under-keel clearance assessment when combined with tide and water-level data. IHO published S-102 edition 1.0.0 in 2012 and edition 2.x in the early 2020s. It is distinct from the navigation chart S-101, which carries the validated charted depths for safety of navigation.