gistfile1.txt

distance: function(lat1, lon1, lat2, lon2) {
    var p = 0.017453292519943295;
    var c = Math.cos;
    var a = 0.5 - c((lat2 - lat1) * p)/2 +
            c(lat1 * p) * c(lat2 * p) *
            (1 - c((lon2 - lon1) * p))/2;

    return (12742 * Math.asin(Math.sqrt(a))) * 1000;
},

angle: function(lat1, lon1, lat2, lon2) {
    var dLon = (lon2 - lon1);

    var y = Math.sin(dLon) * Math.cos(lat2);
    var x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1)
            * Math.cos(lat2) * Math.cos(dLon);

    var brng = Math.atan2(y, x);

    brng = this.rad2deg(brng);
    brng = (brng + 360) % 360;

    return brng;
},