
Although the RENC distribution mechanism is recommended by the IHO, some Hydrographic Organizations distribute their ENCs through other channels.
Countries as Canada, South Korea, Japan or Australia distribute their ENC directly or through chart chandlers.
Under the "Freedom of Information" philosophy the USA offers their ENCs for free on the NOAA Website.
The figure presents the data provision from a Hydrographic Office to a presentation on an ECDIS screen.
ENC have to be processed at SENC to be presented correctly. Two different methods are available:
The latter is mostly offered by ECDIS manufactures acting as Vallue Added Reseller (VAR). The pre-processing to the required SENC format saves a lot of time and is more user friendly.
ECDIS is able to process a variety of official and private data. Accordingly, back-up requirements are different.
The Nautical Institute has provided an excellent overview about that. They kindly permitted the reproduction of the diagram.
Dynamic Licensing is a service started officially spring 2009 and is provided exclusively by Jeppesen Marine. Certain ECDIS producers announced to implement this added value as a part of their products.
ECDIS user acquires precisely those ENC licenses they need exactly when they need them.
The licenses disappear after a specified period of time. Thus the service allows a better control of the costs and users are not forced to carry more ENC licenses than necessary.