How do we recognise an official ENC?

When you are buying:

Only authorized distributors sell official ENCs as an ENC service, which includes the delivery of update information. The distributors are authorized either directly by the originating Hydrographic Office or by a cooperation of Hydrographic Offices. The list can be checked on the official site of the Hydrographic Office

When used in an ECDIS:

ECDIS distinguishes an official ENC from unofficial data.When unofficial data is used, ECDIS informs mariners that they must navigate by means of an official up to date paper chart by a warning, which appears continuously on the screen.

If unofficial data is shown on the ECDIS display, its boundary is to be identified by a special line style.This boundary is visualized as a “one-sided” RED line with the diagonal stroke on the non-HO side of the line.

Where can we get official ENCs?

The International Hydrographic Organisation (IHO) provides an interactive web catalogue ( displaying the status of worldwide ENC production. This system has pointers for guiding users to ENC suppliers and distributors. A three-colour scheme is used to distinguish between degrees of accessibility.

This catalogue indicates that a considerable number of ENCs have been or are being produced by Hydrographic Offices. It also shows that only a part of the issued data has been released and made available to the market.