Which projection is one of the most famous and widely used for sea navigation, with distortion beyond 70° latitude?

• A. Gall Projection
• B. Miller Projection
• C. Mercator Projection
• D. Cassini Projection

Answer: (C)

The key idea is how a map projection handles direction and plotting courses. The Mercator projection is designed so that lines of constant compass bearing (rhumb lines) appear as straight lines on the map. That means a navigator can plot and follow a steady heading easily, which is exactly why this projection became the standard for sea navigation.

This usefulness comes with a trade-off: distortion of size grows as you move away from the equator. Near the poles, the distortion becomes extreme, so land areas are shown much larger than they are in reality—hence the note about distortion beyond 70° latitude. Other projections may reduce size distortion or preserve area, but they don’t provide the straightforward straight-line bearing property that Mercator offers for navigation.