A rhumb line is a path with constant bearing as measured relative to which reference?

A rhumb line is a path with constant bearing as measured relative to which reference?

• A. True or magnetic north
• B. True north
• C. Magnetic north
• D. Geographic north

Answer: (A)

A rhumb line is defined by keeping a constant bearing as you move, which means the bearing is measured against a reference direction of north. In navigation and surveying you can use true north (geographic north) when plotting on charts or magnetic north when following a compass. Because the reference north can be either true or magnetic depending on how you’re measuring, the constant bearing of a rhumb line applies to both possibilities. That’s why the best choice is that the constant bearing is measured relative to true or magnetic north. Using only one reference would miss common practice: charts typically use true north, while compasses indicate magnetic north, and the line remains constant in either frame with the appropriate bearing.

A rhumb line is defined by keeping a constant bearing as you move, which means the bearing is measured against a reference direction of north. In navigation and surveying you can use true north (geographic north) when plotting on charts or magnetic north when following a compass. Because the reference north can be either true or magnetic depending on how you’re measuring, the constant bearing of a rhumb line applies to both possibilities. That’s why the best choice is that the constant bearing is measured relative to true or magnetic north. Using only one reference would miss common practice: charts typically use true north, while compasses indicate magnetic north, and the line remains constant in either frame with the appropriate bearing.