Which projection preserves angles, making it ideal for navigational purposes?

The Mercator projection is specifically designed to preserve angles, which is a critical feature for navigation. This characteristic allows navigators to plot a straight-line course on a map while maintaining consistent compass bearings. Such a property is valuable for marine navigation, where maintaining a constant heading is often necessary.

The Mercator projection does so by representing meridians as equally spaced vertical lines, while parallels are represented as horizontal lines that are spaced increasingly farther apart as they move away from the equator. This transformation distorts area, making landmasses appear larger than they are, particularly near the poles, but it ensures that angles remain true.

In contrast, other projections may prioritize accurate size representation (like equal-area projections) or maintain distance from a central point (as in equidistant projections), but they do not maintain the angle fidelity that is crucial for navigation. The azimuthal projection, while preserving directions from a central point to any other point on the map, does not preserve angles overall since it represents the earth's surface in a way that can distort angular relationships as one moves away from the center. Thus, the Mercator projection stands out as the ideal choice for navigational purposes due to its ability to maintain angle accuracy.