Which projection is used for navigation by transpolar or trans-oceanic routes?

• A. Orthographic Projection
• B. Gnomonic Projection
• C. Stereographic Projection
• D. Lambert Conformal Projection

Answer: (B)

Great-circle paths are the shortest routes between two points on a sphere, so navigators want a map where those paths appear as straight lines. The gnomonic projection does exactly that: every great circle on the globe maps to a straight line on the plane. That makes plotting long transpolar or trans-oceanic routes straightforward—draw a straight line on the map, and you’re tracing the shortest path on Earth. The projection is centered on the sphere’s center, which means it highlights these great-circle routes as continuous straight lines, ideal for planning.

Other projections don’t offer that same convenience. Orthographic shows the globe as a perspective image from space and distorts navigation paths, not giving clean straight-line routes. Stereographic preserves angles locally but doesn’t convert great circles into straight lines in general, so plotting a true shortest path isn’t as intuitive. Lambert conformal preserves shapes along standard parallels but also doesn’t map all great circles to straight lines, limiting its usefulness for straightforward navigation planning.