What are the two types of chart projections used by the US Navy?

The two types of chart projections used by the US Navy are Mercator and Gnomonic.

The Mercator projection is widely utilized for its ability to display lines of constant course, or rhumb lines, as straight segments, making it particularly useful for navigation over long distances. This projection maintains angles and shapes, which is essential for navigating with precision on a flat representation of the Earth.

On the other hand, the Gnomonic projection is beneficial for plotting great circles, the shortest path between two points on a sphere, which is crucial for long-distance navigation. In this projection, all great circle routes are indicated as straight lines, allowing for more efficient planning and navigation on open waters.

Together, these two projections encompass key navigational needs, with the Mercator favoring coastal and local navigation and the Gnomonic facilitating long-range strategic movement. The other answer choices do not represent the primary projections used by the US Navy in nautical charts.