Calculate distance between two GPS coordinates

This code sample will allow you to calculate the distance between two points (GPS coordinates).

function calcLatLonDistance(lat1, lon1, lat2, lon2) {
    if (!lat1 || !lat2 || !lon1 || !lon2) {
        return;
    }
    if (typeof (Number.prototype.toRadians) === "undefined") {
        Number.prototype.toRadians = function () {
            return this * Math.PI / 180;
        };
    }
    var R = 6371; // km
    var φ1 = lat1.toRadians();
    var φ2 = lat2.toRadians();
    var Δφ = (lat2 - lat1).toRadians();
    var Δλ = (lon2 - lon1).toRadians();
    var a = Math.sin(Δφ / 2) * Math.sin(Δφ / 2) +
        Math.cos(φ1) * Math.cos(φ2) *
        Math.sin(Δλ / 2) * Math.sin(Δλ / 2);
    var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
    var d = R * c;
    return parseInt(d * 0.621371);
}

Directions:
- call calcLatLonDistance(lat1, lon1, lat2, lon2);

Note:
This snippet focuses on iOS development. Make sure to verify/adapt any vendor prefixes. Back to main listing.

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