Ever wondered how to measure distance on a globe?
Great-circle distance
Ever wondered how to measure distance on a globe?
Imagine you're planning a trip from Paris to Tokyo. You want to know the shortest path across the Earth.
Think of the Earth as a giant ball. The shortest path between two cities isn't a straight line but follows a curved path on the ball's surface. This path is called a great-circle route.
Example
Paris is at 48.8566° N, 2.3522° E, and Tokyo is at 35.6895° N, 139.6917° E. The great-circle distance would be the straight line connecting these two points on the Earth's surface.
Remember this
The great-circle distance formula helps find the shortest path between two points on a sphere.
Text adapted from Wikipedia, licensed under CC BY-SA 4.0.
Related concepts
Euclidean distance
Euclidean distance formula: √((x2 - x1)² + (y2 - y1)²)
Euclidean geometry
Euclidean distance measures absolute position in space
Mahalanobis distance
Mahalanobis distance formula: D^2 = (x - μ)'Σ^(-1)(x - μ)
Riemannian manifold
Riemannian manifolds generalize Euclidean space concepts like distance and curvature
Minkowski spacetime
Minkowski distance formula: D = (Σ |x_i - y_i|^p)^(1/p)
Distance transform
Manhattan distance formula: |x1 - x2| + |y1 - y2|
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