Buoy, position and fault: three distinct records

A buoy, its published position and its symbol on a display belong to three different layers. The object exists at sea; a record describes an aid with an identity and date; equipment presents received or stored information.

These layers often concern the same aid, but they are not three independent confirmations. Separating them improves chart interpretation and the quality of a report.

A floating buoy can move within the movement allowed by its mooring. A difference from a published record can also involve positional error, mistaken identity, outdated information or displacement of the aid.

The discrepancy is evidence to interpret, not an already known cause. Without geometry, uncertainty and appropriate confirmation, apparent separation between two symbols cannot measure the extent of possible displacement.

AIS AtoN is AIS information concerning an aid to navigation. In physical implementation the transmitting station is installed on the physically existing aid.

In synthetic implementation the physical aid also exists, but equipment elsewhere transmits the information. In virtual implementation the marked position has no corresponding physical aid.

The main distinction is the relationship between the represented object and message origin.

“Synthetic” does not mean an imaginary buoy. “Virtual” does not mean a physical buoy the observer failed to see.

A display may present these messages using its own conventions and attributes; equipment does not all show identical information. A symbol alone establishes neither recent reception, inspection of the aid nor light operation.

The actual system’s data origin and displayed attributes need to be understood.

A clear report identifies location, time, conditions and the observed issue. Trinity House provides a dedicated page for reporting hazards and aid observations within its remit, requesting location and issue details.

This is a British institutional reporting example; elsewhere the competent authority should be consulted. This content submits no reports, and community information remains distinct from an official notice.

The figure maps relationships between records rather than providing a chart with usable coordinates. To understand a discrepancy, first ask what each layer actually states.

Incomplete recognition helps describe attributes; charted marks explains published notation. Together they allow discussion of the same aid without confusing observation, documentation and interpretation.