Chart Navigation & Plotting · Great Circle — Mercator Appearance

On a Mercator chart, a great-circle track between two points in the same hemisphere appears as a line that:

Explanation

Because the Mercator projection expands higher latitudes, the great circle (which reaches higher latitude than the rhumb line) plots as a curve bowing toward the nearer pole. The rhumb line plots as a straight line.

Authority: Bowditch (Pub. No. 9)

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