百度地图和高德地图坐标系的互相转换

GPS、谷歌、百度、高德坐标相互转换

一、在进行地图开发过程中，我们一般能接触到以下三种类型的地图坐标系：

1.WGS－84原始坐标系，一般用国际GPS纪录仪记录下来的经纬度，通过GPS定位拿到的原始经纬度，Google和高德地图定位的的经纬度（国外）都是基于WGS－84坐标系的；但是在国内是不允许直接用WGS84坐标系标注的，必须经过加密后才能使用；

2.GCJ－02坐标系，又名“火星坐标系”，是我国国测局独创的坐标体系，由WGS－84加密而成，在国内，必须至少使用GCJ－02坐标系，或者使用在GCJ－02加密后再进行加密的坐标系，如百度坐标系。高德和Google在国内都是使用GCJ－02坐标系，可以说，GCJ－02是国内最广泛使用的坐标系；

3.百度坐标系:bd-09，百度坐标系是在GCJ－02坐标系的基础上再次加密偏移后形成的坐标系，只适用于百度地图。(目前百度API提供了从其它坐标系转换为百度坐标系的API，但却没有从百度坐标系转为其他坐标系的API)

二、为什么会发生偏移？

1.由于坐标系之间不兼容，如在百度地图上定位的经纬度拿到高德地图上直接描点就肯定会发生偏移；只考虑国内的情况，高德地图和Google地图是可以不经过转换也能够准确显示的（在国内用的都是GCJ－02坐标系）；下面是收录了网上的WGS－84，GCJ－02，百度坐标系(bd-09)之间的相互转换的方法，经测试，是转换后相对准确可用的。

三、代码

Java：

package com.zehin.map.util;

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);  
    }  
}

c#：

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 bool 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[] Gps84ToGcj02(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[] Gcj02ToGps84(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 };
    }
    /// <summary>
    /// 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 
    /// 高德谷歌转为百度
    /// </summary>
    /// <param name="lat"></param>
    /// <param name="lon"></param>
    /// <returns></returns>
    public static double[] Gcj02ToBd09(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;
    }

    /// <summary>
    /// 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
    /// 百度坐标转为高德谷歌坐标
    /// </summary>
    /// <param name="lat"></param>
    /// <param name="lon"></param>
    /// <returns></returns>
    public static double[] Bd09ToGcj02(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;
    }

    /// <summary>
    /// gps84转为bd09
    /// GPS坐标转为百度坐标
    /// </summary>
    /// <param name="lat"></param>
    /// <param name="lon"></param>
    /// <returns></returns>
    public static double[] Gps84ToBd09(double lat, double lon)
    {
        double[] gcj02 = Gps84ToGcj02(lat, lon);
        double[] bd09 = Gcj02ToBd09(gcj02[0], gcj02[1]);
        return bd09;
    }
    /// <summary>
    /// 百度坐标转成GPS坐标
    /// </summary>
    /// <param name="lat"></param>
    /// <param name="lon"></param>
    /// <returns></returns>
    public static double[] Bd09ToGps84(double lat, double lon)
    {
        double[] gcj02 = Bd09ToGcj02(lat, lon);
        double[] gps84 = Gcj02ToGps84(gcj02[0], gcj02[1]);
        //保留小数点后六位  
        gps84[0] = Retain6(gps84[0]);
        gps84[1] = Retain6(gps84[1]);
        return gps84;
    }

    /// <summary>
    /// 保留小数点后六位 
    /// </summary>
    /// <param name="num"></param>
    /// <returns></returns>
    private static double Retain6(double num)
    {
        String result = String.Format("%.6f", num);
        return Double.Parse(result);
    }
}

作者：青檬可乐_ 
链接：https://www.jianshu.com/p/d3dd4149bb0b 
來源：简书