angular-haversine.js

(function () {
    'use strict';

    angular.module('benharold.haversine', []).constant('haversine', (function () {

        var toRad = function (num) {
            return num * Math.PI / 180;
        };

        return function haversine(start, end, options) {
            var km = 6371;
            var mile = 3960;
            options = options || {};

            var R = options.unit === 'km' ? km : mile;

            var dLat = toRad(end.latitude - start.latitude);
            var dLon = toRad(end.longitude - start.longitude);
            var lat1 = toRad(start.latitude);
            var lat2 = toRad(end.latitude);

            var a = Math.sin(dLat / 2) * Math.sin(dLat / 2) +
                Math.sin(dLon / 2) * Math.sin(dLon / 2) * Math.cos(lat1) * Math.cos(lat2);
            var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

            if (options.threshold) {
                return options.threshold > (R * c)
            } else {
                return R * c
            }
        };

    })());

})();