S-57 DATASETS ON UNSPECIFIED DATUM

Positions obtained from Global Navigation Satellite Systems, such as
GPS, are normally referred to WGS84 Datum. The differences between
satellite-derived positions and positions on this cell cannot be
accurately determined; the estimated value of the difference for this
region of the chart is shown in the INFORM attribute. Mariners are
warned that these differences MAY BE SIGNIFICANT TO
NAVIGATION and are therefore advised to confirm GPS positions
shown in the chart display using alternative navigational techniques
particularly when closing the shore or navigating in the vicinity of
dangers.