Which bathymetric feature is shown only on Provisional-Edition maps?

Which bathymetric feature is shown only on Provisional-Edition maps?

• A. Sunken rock
• B. Channel
• C. Foreshore flat
• D. Exposed wreck

Answer: (A)

The key idea is how provisional hydrographic charts handle uncertainties and newly observed hazards. Provisional-Edition maps are used when survey data are partial or awaiting confirmation, so they highlight features that might pose a risk but aren’t yet fully verified. A sunken rock fits this: it’s a submerged hazard that can be difficult to confirm or reclassify with confidence until new soundings or surveys are done. Showing it on provisional charts warns mariners to exercise extra caution and verify depths before relying on the chart for navigation. Other features like a channel, foreshore flat, or an exposed wreck are more established aspects of the seabed or shoreline that get represented on standard charts once they’re well documented, so they aren’t restricted to provisional editions.

The key idea is how provisional hydrographic charts handle uncertainties and newly observed hazards. Provisional-Edition maps are used when survey data are partial or awaiting confirmation, so they highlight features that might pose a risk but aren’t yet fully verified. A sunken rock fits this: it’s a submerged hazard that can be difficult to confirm or reclassify with confidence until new soundings or surveys are done. Showing it on provisional charts warns mariners to exercise extra caution and verify depths before relying on the chart for navigation. Other features like a channel, foreshore flat, or an exposed wreck are more established aspects of the seabed or shoreline that get represented on standard charts once they’re well documented, so they aren’t restricted to provisional editions.