About Halfway

Halfway is a daily geography game. Every day you get three routes between world cities and one job: find the halfway point of the shortest flight between them.

It looks easy until you remember the Earth is round. The shortest path between two places follows a great circle, and on the flat maps we all learned from, that path curves toward the pole. Most first guesses land hundreds or thousands of kilometres from the real midpoint.

How the numbers are calculated

Distances and midpoints are computed on a sphere with a radius of 6,371 km. That is accurate to within about 0.5% of real-world geodesic distances. Flight times are estimates at an average speed of 850 km/h plus 30 minutes for take-off, landing and taxi. The game map uses the Mercator projection on purpose, because that is the view that makes the puzzle hard.

Map data comes from Natural Earth, a public-domain dataset, packaged by the world-atlas project. City and capital names and coordinates come from GeoNames, licensed under CC BY 4.0.

Contact

Suggestions, bug reports and route ideas are welcome at contact@thehalfwaygame.com.