USCG Exam PracticeLatitude, longitude, and geographic coordinates
A USCG Notice to Mariners lists a waypoint for a regulated regatta area using geographic coordinates that are not labeled NAD 83. The vessel's chart is referenced to NAD 83. Which statement correctly describes the required procedure before plotting that waypoint?
- A. The coordinates may be plotted directly, because all federal publications default to WGS 84, which is equivalent to NAD 83 for practical purposes.
- ✓ The appropriate datum corrections published on the NAD 83 chart must be applied to the coordinates before plotting.Correct
- C. The coordinates must be converted to magnetic bearing and distance before plotting on any NAD 83 chart.
- D. The coordinates may not be plotted on the NAD 83 chart under any circumstances, as unlabeled coordinates are invalid for navigation.
Why B is correct
33 CFR §100.01(b) explicitly states that geographic coordinates without the NAD 83 reference may be plotted on NAD 83 charts only after application of the appropriate corrections published on that particular chart. The regulation does not prohibit plotting, nor does it authorize direct plotting without correction.
Cited:33 CFR §100.01