Carriage of electronic charting systems by coastal pilots—advisory notice

The purpose of this advisory note is to inform pilots and pilotage providers of AMSA’s requirements when a coastal pilots decide to utilise their own system of electronic charting to assist with pilotage in the Great Barrier Reef or Torres Strait.

ECDIS: Electronic Chart Display and Information System
ECS: Electronic Charting Systems
ENC: Electronic Navigational Charts
RNC: Raster Navigational Chart
AHS: Australian Hydrographic Service
IC-ENC: International Centre for ENC
SENC: System ENC
S57: IHO data format and specification which governs the content, creation and display of ENC.
S63: IHO ENC data protection scheme.

ECDIS: Electronic Chart Display and information systems

An ECDIS meets the IMO/SOLAS and NSCV requirements if used with up to date offi cial electronic charts. Because of other requirements for example backup arrangements, these are ship borne systems only. 

An ECDIS comprises type approved hardware and software, using only authorised (offi cial) chart data. This chart data is ENC or, where an ENC does not exist, RNC. 

Most ECDIS convert each ENC cell from S57 format into an internal machine language format called System ENC or SENC. 

Each ECDIS software manufacturer has its own SENC format. Consequently the SENC format may differ between ECDIS manufacturers.

ECS: Electronic Charting Systems 

This is a generic term for chart display systems other than ECDIS that are capable of displaying a vessels position on a chart image on a screen. This equipment may range from a simple hand held GPS to a chart plotter or to a sophisticated stand-alone computer system. Some may be able to perform many of the functions of an ECDIS. 

There are no agreed standards for ECS or the versions of the charts they use. Because of this, ECS are not recognised as an alternative to paper charts for SOLAS class vessels for navigational purposes. 


Types of Official Electronic Charts Official electronic charts are those issued officially by, or on the authority of, a Government, authorised Hydrographic Office or other government institution. In Australia the relevant Hydrographic authority is the Australian Hydrographic Service (AHS). 

The charts used in ECS come in a variety of forms. Some rely on unofficial, commercially produced charts ranging from very simple line drawings to images that closely resemble paper charts. Some may use official electronic navigational charts.

RNC: Raster Navigational Chart 

A RNC is a digital copy of an official paper chart which is geo-referenced to WGS-84. These charts are not intelligent in that the chart features can not be changed or interrogated.

ENC: Electronic Navigational Charts 

An ENC is an offi cial vector electronic chart produced in International Hydrographic Organisation (IHO) “S57” Edition 3.1 format and protected using the IHO “S63” data protection scheme. 

Note: AMSA is aware that there is some confusion in the marine community in relation to “S57” and ENC’s. 

Please note that “S57” is an IHO transfer format, and is able to be produced by a number of sources, however it is not an offi cial ENC. Only an official ENC that carries the warranty of a National Hydrographic Office, complies with SOLAS requirements. 

The Australian Hydrographic Service (AHS) does not publish “S57” formatted data. 

Availability of ENC & RNC

Product Availability Distributor
Australian ENC (Vector Charts) General public The International Centre for ENC (IC-ENC) and Primary global distribution networks
Seafarer RNC (Raster Charts) General public AHS Chart Agents (Distributors)
Seafarer ENC (Vector Charts) Only available to Australian and NZ Defence Forces, Australian Port Authorities, Maritime Safety Authorities and Marine Pilots AHS

Note: Australian pilot companies are permitted to purchase (direct from the AHS only) Australian ENC’s of their area of operation at equivalent rates to the ICENC but with no minimum spend policy.

Seafarer ENC (Vector charts) supplied directly by the AHS are supported by a fortnightly CD based update service. The service includes updated replacements for all Australian cells affected by the latest published Permanent, Temporary and Preliminary Notices to Mariners.

For further information contact the AHS Licensing Manager. 

Phone: 02 4223 6500 

Fax: 02 4223 6599 


All licensed areas covered by coastal pilots have full ENC coverage. 

Guidelines for coastal pilots regarding the carriage of electronic charting systems 

AMSA does not require pilots to carry any electronic charting system while piloting. However if pilots do decide to carry any system of electronic charting, AMSA requires that the charts used must be an ENC that is up to date and issued offi cially by, or on the authority of, a Government, authorised Hydrographic Office or other government institution, or accessed through the IC-ENC. 

Pilots must not use any ECS that does not comply with this guideline.

Last updated: 21 September 2020