General Mathematics · Earth geometry · manipulative

Great circles on the Earth

Slice a globe with a flat plane. If the plane passes through the centre you get a great circle; if it misses the centre you get a smaller one.

plane through centre plane off centre shortest route

Drag to orbit · north stays on the axis and moves with the globe · scroll to zoom

Cutting planes

0°
45°N
Show the planes
the flat cut, not just the circle
Parallel of latitude
the off-centre cut
Meridians
great circles through both poles
Shortest route
great-circle arc between two cities

Two cities

45°N
60°W
45°N
60°E

Radii