S-101 ENC Product Specification

S-101 is the IHO product specification for the next-generation Electronic Navigational Chart, the planned successor to the S-57-based ENC. Built on the S-100 Universal Hydrographic Data Model, it carries richer feature and portrayal catalogs, supports dynamic data overlays, and improves update handling versus S-57. IHO adopted S-101 edition 1.0.0 in 2018, with a dual-fuel transition period in which S-57 ENCs and S-101 charts coexist in ECDIS through the 2020s. It is the chart layer of the wider S-1xx product family.