@ue-too/border / intermediatePointOnGreatCircle

Function: intermediatePointOnGreatCircle()

intermediatePointOnGreatCircle(startCoord, endCoord, fraction): GeoCoord

Defined in: greateCircle.ts:38

Calculates an intermediate point along a great circle path.

Parameters

startCoord

GeoCoord

The starting geographic coordinate

endCoord

GeoCoord

The ending geographic coordinate

fraction

number

The fraction along the path (0 = start, 1 = end, 0.5 = midpoint)

Returns

GeoCoord

The intermediate point at the specified fraction

Remarks

Given two points on Earth's surface, this finds a point at a specified fraction along the great circle (shortest) path between them.

Uses the spherical interpolation formula for accurate results on a sphere.

Example

const nyc = { latitude: 40.7128, longitude: -74.0060 };
const london = { latitude: 51.5074, longitude: -0.1278 };

// Find point 25% of the way from NYC to London
const quarter = intermediatePointOnGreatCircle(nyc, london, 0.25);

// Find point 75% of the way
const threeQuarters = intermediatePointOnGreatCircle(nyc, london, 0.75);