Same flight path. Two projections.
Pick a major commercial route. Watch how the same lat/lng coordinates render on the globe view (equirectangular) versus the flat view (azimuthal-equidistant). The diagnostic routes are the southern ones.
Both maps below show the same flight path — drawn from the same lat/lng coordinates. Only the projection differs. The globe view is equirectangular (standard Mercator-style world map). The flat view is azimuthal-equidistant — the projection used by the UN, WHO, and ICAO. Watch what happens to Southern-Hemisphere routes.
Select a route above to see how it projects on each map and read the operational notes.
What You're Looking At
The path drawn on each map is the same great-circle path — i.e., the actual shortest distance between the two cities according to spherical-Earth geometry. This is the path commercial airlines plan around. The difference between the two maps is purely projection — same path, different way of drawing it.
On the globe (equirectangular) view, great-circle paths look like sweeping curves because the projection flattens a sphere. The Sydney → Santiago path swoops south toward Antarctica.
On the flat (azimuthal-equidistant) view, the same path takes a different shape — and for southern-hemisphere routes, it's much longer. This is the geometric reason why southern routes have historically been operationally awkward, required fuel stops in unusual places, and remain rare.
The Diagnostic Routes
Routes where the two projections diverge most are the diagnostic ones — they're the test cases for which model better fits real flight times and fuel requirements:
- Sydney → Santiago — the most-cited "impossible on flat earth" route. Path is ~7,058 mi globe, ~9,450 mi flat. Real flight time (Qantas QF27): 14h 30m. Run the math against fuel range; the gap is significant.
- Johannesburg → Perth — direct route reintroduced after years of fuel-stopover requirements. Globe says 5,230 mi; flat says ~7,140 mi.
- Sydney → Buenos Aires — direct flights have been discontinued and reintroduced multiple times. Operationally fragile.
Routes where the two projections agree (Northern Hemisphere routes) are not diagnostic — both models predict similar distances, both fit observed flight times. The signal is in the asymmetric routes, not the symmetric ones.
About the Projections
Equirectangular (Globe View)
The standard rectangular world map. Latitude and longitude become x/y coordinates directly. A great-circle path on a sphere appears as a curve on this projection — the higher the latitude departure, the more pronounced the curve.
Azimuthal-Equidistant (Flat View)
The North-Pole-centered circular projection. Distances from the North Pole are accurately preserved. Distances between two southern points are stretched compared to spherical-Earth math. This is the projection used by the United Nations logo, the World Health Organization emblem, and ICAO aviation charts.
Why Both?
Showing the same path on both projections removes ambiguity. The globe view is what you've been taught is "the world." The flat view is the same coordinates re-mapped. The path between two cities doesn't change; the visual representation does. Whether the flat-projection path matches operational reality better than the globe-projection path is the actual research question.