//地球坐标系WGS84转火星坐标系GCJ02
var pi = 3.14159265358979324;
var a = 6378245.0;
var ee = 0.00669342162296594323;
/*判断是否在国内，不在国内则不做偏移*/
function outOfChina(lon, lat)
{
    if ((lon < 72.004 || lon > 137.8347)&&(lat < 0.8293 || lat > 55.8271)){
        return true;
    }else {
        return false;
    }
}
function transformLat(x,y)
{
    var ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
    ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
    ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
    ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
    return ret;
}

function transformLon(x,y)
{
    var ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
    ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
    ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
    ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
    return ret;
}

export function transformWGSGCJ2(wgLat,wgLon)
{
    var mars_point={lon:0,lat:0};
    if (outOfChina(wgLat, wgLon))
    {
        mars_point.lat = wgLat;
        mars_point.lon = wgLon;
        return;
    }
    var dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
    var dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
    var radLat = wgLat / 180.0 * pi;
    var magic = Math.sin(radLat);
    magic = 1 - ee * magic * magic;
    var sqrtMagic = Math.sqrt(magic);
    dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
    dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
    mars_point.lat = wgLat + dLat;
    mars_point.lon = wgLon + dLon;
    return mars_point
}
