GPS坐标转化工具类

坐标说明

目前比较流行的gps坐标为原始坐标，火星坐标，百度坐标等。

• 原始坐标：未经过任何处理的坐标。
• 火星坐标：中国国家XXX机构说是为了防止安全(其实也不安全)，也叫中国坐标。
• 百度坐标：百度地图在火星坐标基础上进行了偏移。类似的有高德地图坐标等。

• 谷歌坐标：在国外就是原始坐标，但是针对国内用户，谷歌坐标需要遵守中国的规定，所以谷歌坐标在国内并不是原始坐标，而是经过了一定的偏移。

  下面为原始坐标、火星坐标、百度坐标的相互转化算法工具类。

/**
 * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的互转 Created by Kang on 18/07/03.
 */
public class GPSUtil {
    public static double pi = 3.1415926535897932384626;
    public static double x_pi = 3.14159265358979324 * 3000.0 / 180.0;
    public static double a = 6378245.0;
    public static double ee = 0.00669342162296594323;

    public 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;
    }

    public 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;
    }

    public static double[] transform(double lat, double lon) {
        if (outOfChina(lat, lon)) {
            return new double[] { lat, lon };
        }
        double dLat = transformLat(lon - 105.0, lat - 35.0);
        double dLon = transformLon(lon - 105.0, lat - 35.0);
        double radLat = lat / 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);
        double mgLat = lat + dLat;
        double mgLon = lon + dLon;
        return new double[] { mgLat, mgLon };
    }

    public 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;
    }

    /**
     * 84 to 火星坐标系 (GCJ-02) World Geodetic System ==> Mars Geodetic System
     * 
     * @param lat
     * @param lon
     * @return
     */
    public static double[] gps84_To_Gcj02(double lat, double lon) {
        if (outOfChina(lat, lon)) {
            return new double[] { lat, lon };
        }
        double dLat = transformLat(lon - 105.0, lat - 35.0);
        double dLon = transformLon(lon - 105.0, lat - 35.0);
        double radLat = lat / 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);
        double mgLat = lat + dLat;
        double mgLon = lon + dLon;
        return new double[] { mgLat, mgLon };
    }

    /**
     * * 火星坐标系 (GCJ-02) to 84 * * @param lon * @param lat * @return
     */
    public static double[] gcj02_To_Gps84(double lat, double lon) {
        double[] gps = transform(lat, lon);
        double lontitude = lon * 2 - gps[1];
        double latitude = lat * 2 - gps[0];
        return new double[] { latitude, lontitude };
    }

    /**
     * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 将 GCJ-02 坐标转换成 BD-09 坐标
     * 
     * @param lat
     * @param lon
     */
    public static double[] gcj02_To_Bd09(double lat, double lon) {
        double x = lon, y = lat;
        double z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * x_pi);
        double theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * x_pi);
        double tempLon = z * Math.cos(theta) + 0.0065;
        double tempLat = z * Math.sin(theta) + 0.006;
        double[] gps = { tempLat, tempLon };
        return gps;
    }

    /**
     * * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 * * 将 BD-09 坐标转换成GCJ-02 坐标 *
     * * @param bd_lat * @param bd_lon * @return
     */
    public static double[] bd09_To_Gcj02(double lat, double lon) {
        double x = lon - 0.0065, y = lat - 0.006;
        double z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * x_pi);
        double theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * x_pi);
        double tempLon = z * Math.cos(theta);
        double tempLat = z * Math.sin(theta);
        double[] gps = { tempLat, tempLon };
        return gps;
    }

    /**
     * 将gps84转为bd09
     * 
     * @param lat
     * @param lon
     * @return
     */
    public static double[] gps84_To_bd09(double lat, double lon) {
        double[] gcj02 = gps84_To_Gcj02(lat, lon);
        double[] bd09 = gcj02_To_Bd09(gcj02[0], gcj02[1]);
        return bd09;
    }

    public static double[] bd09_To_gps84(double lat, double lon) {
        double[] gcj02 = bd09_To_Gcj02(lat, lon);
        double[] gps84 = gcj02_To_Gps84(gcj02[0], gcj02[1]);
        // 保留小数点后六位
        gps84[0] = retain6(gps84[0]);
        gps84[1] = retain6(gps84[1]);
        return gps84;
    }

    /**
     * 保留小数点后六位
     * 
     * @param num
     * @return
     */
    private static double retain6(double num) {
        String result = String.format("%.6f", num);
        return Double.valueOf(result);
    }