Why Flight Paths Curve: Great-Circle Routes Explained
The shortest path between two points on a sphere is not usually a straight line on a flat world map. That apparent curve is a projection effect, and it is the reason many long-distance route animations arc toward higher latitudes.
The geometric idea
A great circle is created by slicing a sphere with a plane that passes through its center. The equator is one example; any pair of non-antipodal points also defines a great-circle path.
On a globe, the great-circle arc is the shortest surface path. When projected onto a rectangular map, the same arc can appear to bow north or south because the projection stretches and rearranges the spherical surface.
How TripAnim uses airport data
TripAnim starts with the published latitude and longitude of the selected airports, interpolates points along the great-circle arc, and draws those points on the 3D globe. Route pages report an approximate great-circle distance using the same geographic concept.
The model is intentionally geographic. It does not include winds, restricted airspace, air-traffic instructions, weather deviations or the exact track of a particular flight.
What the animation can and cannot claim
It can accurately show the endpoints, relative direction and shortest spherical path between them. It can explain why a transatlantic or transpacific route appears curved.
It should not be described as a live tracker, schedule, navigation product or verified airline routing. Real operations may follow a different path and change from day to day.
A simple verification exercise
Open New York to Tokyo in overview mode, then compare the arc on the globe with how you expect it to look on a flat map.
- Endpoints match the intended IATA codes
- Arc interpreted on a globe
- Distance described as approximate
- No operational flight claim
- Source methodology disclosed to viewers when relevant
A repeatable workflow
- Choose distant airportsA long route makes the projection effect easier to see.
- Use overview cameraKeep enough globe visible to understand the arc.
- Inspect the curvatureCompare the spherical path with a flat-map expectation.
- Describe it accuratelyCall it a geographic great-circle visualization.
Does a curved line mean the aircraft flies farther?
Not necessarily. On a globe, the curved-looking line often represents the shortest surface path.
Does TripAnim show the exact track of a flight?
No. It visualizes a geographic great-circle route between airport coordinates.
Why do some routes bend north?
Flat map projections distort spherical geometry; many northern arcs are shorter on the globe than a visually straight flat-map line.
Apply this workflow to your own route
Open the editor, choose your airports and review the complete movement before creating the source video.
Create the routeMethod note: TripAnim visualizes great-circle geography between airport coordinates. It does not provide schedules, live tracking or operational flight plans. Advice was reviewed against the editor available on the date above.
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