ECDIS Block Diagram,


ENC is a acronym for electronic Navigational chart which is a file containing the official chart data that an ECDIS uses.

The IMO defines the ENC as fallows:-

ENC means the database, standardised as to content, structure and format, issued for use with ECDIS on the authority of government-authorised Hydrographic Offices. The ENC contains all the chart information useful for safe navigation, and may contain supplementary information in addition to that contained in the paper, which may be considered necessary for safe navigation.


A. SENC is an acronym for System Electronic Navigational Chart. An ECDIS converts ENC data into its own internal SENC format for optimal chart image creation. SENC data can differ between manufacturers.  

“The System Electronic Navigational Chart (SENC) means a database resulting from the transformation of the ENC by ECDIS for appropriate use, updates to the ENC by appropriate means and other data added by the mariner. It is this database that is actually accessed by ECDIS for the display generation and other navigational functions and is the equivalent to an up-to-date paper chart.” 


A RCDS is an acronym for Raster Chart Display System. A vessel is permitted to sail in RCDS mode if approved by their flag state for geographical areas where there are no ENCs available. For Flag state conformance, vessels must also carry up to date paper charts for these areas. Using RCDS mode in ENC available geographic areas is forbidden. If sailing in RCDS mode then paper charts become the primary form of navigation and the electronic chart is simply an aid to navigation.

How is the chart update process managed?

Chart updates for ECDIS can be done directly to vessels by DVD, e-mail or online. We understand the complexity of managing the changes to chart folios resulting from changing vessels’ trading patterns or available ENC coverage. We can ensure that your vessel can have the latest charts via a variety of update methods.

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