Thomas Gunn Navigation Services Ltd is dedicated to providing a complete catalogue of available ENC's which are sourced from various Hydrographic offices around the world. We are committed to providing a single source for all commercially available ENC data and the updating and support services required to provide a professional service to the end user.

ENCs use 'intelligent' vector data. This data is held in layers and records every feature on a chart such as coastlines, buoys, lights, etc. These features and their attributes (position, colour, shape, etc.) are held in a database that allows them to be selectively displayed and queried. Therefore, ENCs can appear quite different to traditional paper charts.

ENC data must be issued by, or on the authority of, a government-authorised Hydrographic Office. Each country is responsible for producing its own ENCs, which must be updated systematically with all safety critical information and be fully compliant with the International Hydrographic Organisation's (IHO's) S57 Version 3 product standard. Any vessel wishing to use ECDIS as the primary form of navigation i.e. a reduction or eradication of paper charts must use official ENC data as distributed by Primar Stavanger, International Centre for ENC's (Ic-Enc), Japan Hydrogrphic Association (JHA) and other National suppliers from around the world. There are a number of commercial data providers including C-Map and Transas who distribute unofficial vector chart data.

While some nations have produced substantial amounts of ENCs, unfortunately many others still have little or no coverage at all. ENC coverage of high priority areas such as the world's main shipping routes will gradually become available over the next few years, but other areas could take far longer.

The following image provides a current overview of ENC availability.