js 由A、B两点的经纬度计算AB夹角

js 由A、B两点的经纬度计算AB夹角

function getAngle(aLon,aLat, bLon,bLat) {
    var kRadius = 6378137;//地球半径
    var bx = (aLon * Math.PI / 180 - bLon * Math.PI / 180) * (kRadius*Math.cos(bLat*Math.PI/180));
    var by = (aLat * Math.PI / 180 - bLat * Math.PI / 180) * kRadius
    var angle = 0;
    angle = Math.atan2(bx, by) * 180.0 / Math.PI;
    return angle;
}