GPS 偏移校正(WGS-84) 到(GCJ-02) java版本实现

public class EvilTransform {
	
	final static double pi = 3.14159265358979324;

    //
    //
    // a = 6378245.0, 1/f = 298.3
    // b = a * (1 - f)
    // ee = (a^2 - b^2) / a^2;
	final static double a = 6378245.0;
	final static double ee = 0.00669342162296594323;
	
	

    //
    // World Geodetic System ==> Mars Geodetic System
    public static double[] transform(double wgLat, double wgLon)
    {
    	double mgLat=0;
		double mgLon=0;
        if (outOfChina(wgLat, wgLon))
        {
            mgLat = wgLat;
            mgLon = wgLon;
            
        }else{
	        double dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
	        double dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
	        double radLat = wgLat / 180.0 * pi;
	        double magic = Math.sin(radLat);
	        magic = 1 - ee * magic * magic;
	        double sqrtMagic = Math.sqrt(magic);
	        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
	        dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
	        mgLat = wgLat + dLat;
	        mgLon = wgLon + dLon;
        }
        double[] point={mgLat,mgLon};
        return point;
    }

    private static boolean outOfChina(double lat, double lon)
    {
        if (lon < 72.004 || lon > 137.8347)
            return true;
        if (lat < 0.8293 || lat > 55.8271)
            return true;
        return false;
    }

    private static double transformLat(double x, double y)
    {
        double 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;
    }

    private static double transformLon(double x, double y)
    {
        double 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;
    }
}