International Hydrographic Organization (IHO)

The IHO is the intergovernmental body, founded 1921 and based in Monaco, that coordinates national hydrographic offices and sets the standards for charts and nautical publications: S-32 (dictionary), S-57 and S-101 (ENC data), S-52 (ECDIS display), and S-44 (survey accuracy). It does not produce charts itself; member states’ hydrographic offices do, to IHO specification, so an ENC from any member loads and displays consistently in any compliant ECDIS.