怎样算经纬度

//根据经纬度坐标算两点间距离，通用算法，忽略80或54坐标系问题，有误差

// 两点间的距离，单位为米

//javascript编写，可以按需要用其他编程语言转换。
function calcDistance(mX,mY,mX2,mY2) {
var mDistance = 0;
var Lon1 = mX2 * Math.PI / 180;
var Lon2 = mX * Math.PI / 180;
var Lat1 = mY2 * Math.PI / 180;
var Lat2 = mY * Math.PI / 180;
var LonDist = Lon1-Lon2;
var LatDist = Lat1-Lat2;
var xD = Math.abs(mX - mX2);
var yD = Math.abs(mY - mY2);
mDistance = Math.sqrt(Math.pow(xD,2) + Math.pow(yD,2));

var theDist = convertUnits(mDistance);
var u = Math.pow(10,numDecimals);
currentMeasure = parseInt(theDist*u+(5/10))/u;
return currentMeasure;
}

// convert the amounts to new units
function convertUnits(theDist1) {
var theDist = parseFloat(theDist1);
var mDistance = theDist;
mDistance = theDist * (6213711922/10000000000000);
var u = Math.pow(10,numDecimals);
mDistance = parse