37 lines
952 B
JavaScript
37 lines
952 B
JavaScript
((x, y) => {
|
|
'use strict';
|
|
|
|
// haversine :: (Num, Num) -> (Num, Num) -> Num
|
|
let haversine = ([lat1, lon1], [lat2, lon2]) => {
|
|
// Math lib function names
|
|
let [pi, asin, sin, cos, sqrt, pow, round] =
|
|
['PI', 'asin', 'sin', 'cos', 'sqrt', 'pow', 'round']
|
|
.map(k => Math[k]),
|
|
|
|
// degrees as radians
|
|
[rlat1, rlat2, rlon1, rlon2] = [lat1, lat2, lon1, lon2]
|
|
.map(x => x / 180 * pi),
|
|
|
|
dLat = rlat2 - rlat1,
|
|
dLon = rlon2 - rlon1,
|
|
radius = 6372.8; // km
|
|
|
|
// km
|
|
return round(
|
|
radius * 2 * asin(
|
|
sqrt(
|
|
pow(sin(dLat / 2), 2) +
|
|
pow(sin(dLon / 2), 2) *
|
|
cos(rlat1) * cos(rlat2)
|
|
)
|
|
) * 100
|
|
) / 100;
|
|
};
|
|
|
|
// TEST
|
|
return haversine(x, y);
|
|
|
|
// --> 2887.26
|
|
|
|
})([36.12, -86.67], [33.94, -118.40]);
|