This library is deprecated in favor of pault.ag/go/geo, which contains a strict superset of the functionality here.
This module uses the commonly used haversine formula for calculating small distances between two points.
package main
import (
"fmt"
"pault.ag/go/haversine"
)
func main() {
whiteHouse := haversine.Point{Lat: 38.89768, Lon: -77.03653}
eighteenAndF := haversine.Point{Lat: 38.89736, Lon: -77.04173}
fmt.Printf("%f\n", float64(whiteHouse.MetresTo(eighteenAndF)))
/* 451.41 Metres (float64) */
}