Electronic Navigational Charts (ENCs) are official vector charts that conform to strict IHO Specifications that have been issued by or on behalf of a national hydrographic authority.

ENCs, by their very nature, are fully compliant with the International Hydrographic Organisation’s (IHO’s) S57 Version 3 Product Standard, and can only be issued by, or on the authority of, a government-authorised Hydrographic Office (HO). Each IHO member nation is responsible for producing ENCs of its own waters, and systematically updating them with all safety-critical information.

ENCs are the only vector charts that may be used for primary navigation in place of paper charts. When operating with ENCs, an ECDIS can be programmed to automatically trigger alarms to warn of impending dangers and provide significant benefits in terms of maritime safety, risk management, cost savings and other operational efficiencies.

ENCs consist of digitised data that records all the relevant chart features such as coastlines, buoys, lights, etc. These features and their attributes (such as position, colour, shape) are held in a database-like structure that allows them to be selectively displayed and queried, creating the potential to manipulate the chart image when displayed on screen. Because of their vector format, ENCs can also be linked to other onboard systems to provide additional automatic features such as warning alarms.