gps各种地图坐标系转换

原文地址：https://my.oschina.net/fankun2013/blog/338100

地图供应商比较多，产生了许多地图坐标。地图坐标正确转换是个问题。在之前开发地图应用的时候发现从WGS84坐标系（GPS）转换成某个地图坐标系都比较困难。然后只能使用地图供应商提供的webservice接口转换。百度也提供了免费的webservice接口（限制并发量）。对于少数点的转换性能还可以，但是对于非常多点的转换压力比较大（使用多线程并行计算）.个人感觉比较繁琐，而且很难保证转换的稳定性。

时间飞逝，百度地图更新了新版本，给我们带来了福音，map API中自带了相关坐标的转换，这就省事多了。但是其它的地图貌似没有提供转换API.怎么办呢？真是高手在民间呀，哪个牛人透露转换的算法呢？估计是和百度相关的牛人吧。下面是对算法的收集和整理。提供java版本。js版本参考：http://www.oschina.net/code/snippet_260395_39205

这下使用地图转换就比较准确了。

public class CoordinateConvertUtil {
    private static  double PI         = Math.PI;
    private static  double AXIS             = 6378245.0;  //
        private static  double OFFSET             = 0.00669342162296594323;  //(a^2 - b^2) / a^2
        private static  double X_PI        = PI * 3000.0 / 180.0;

    public static void main(String[] args) {
        // 116.39806876799298,39.90830142538959
        // 116.397826,39.90894374525333
        // 116.3978262189183,39.90894374525333
        String lon = "116.391910";
        String lat = "39.906050";
        lon = "";
        lat = "";
        double [] arr2 = bd092GCJ(39.9151, 116.4039595 );
        System.out.println(arr2[0]+ "," + arr2[1]);
        double [] arr = bd092WGS(39.9151, 116.4039595 );
        System.out.println(arr[0]+ "," + arr[1]);
    }

    //GCJ-02=>BD09 火星坐标系=>百度坐标系
    public static double[] gcj2BD09(double glat, double glon){
        double x = glon;
        double y = glat;
        double[] latlon = new double[2];
        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);
        latlon[0] = z * Math.sin(theta) + 0.006;
        latlon[1] = z * Math.cos(theta) + 0.0065;
        return latlon;
    }

    //BD09=>GCJ-02 百度坐标系=>火星坐标系
    public static double[] bd092GCJ(double glat, double glon){
        double x = glon - 0.0065;
        double y = glat - 0.006;
        double[] latlon = new double[2];
        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);
        latlon[0] = z * Math.sin(theta);
        latlon[1] = z * Math.cos(theta);
        return latlon;
    }
    //BD09=>WGS84 百度坐标系=>地球坐标系
    public static double[] bd092WGS(double glat, double glon){
            double[] latlon = bd092GCJ(glat,glon);
            return gcj2WGS(latlon[0],latlon[1]);
        }
        // WGS84=》BD09   地球坐标系=>百度坐标系
        public static double[] wgs2BD09(double wgLat, double wgLon) {
            double[] latlon = wgs2GCJ(wgLat,wgLon);
            return gcj2BD09(latlon[0],latlon[1]);
        }  

    // WGS84=》GCJ02   地球坐标系=>火星坐标系
        public static double[] wgs2GCJ(double wgLat, double wgLon) {
            double[] latlon  = new double[2];
            if (outOfChina(wgLat, wgLon)){
                latlon[0] = wgLat;
                latlon[1] = wgLon;
               return latlon;
             }
            double[] deltaD =  delta(wgLat,wgLon);
            latlon[0] = wgLat + deltaD[0];
            latlon[1] = wgLon + deltaD[1];
            return latlon;
        }
        //GCJ02=>WGS84   火星坐标系=>地球坐标系(粗略)
        public static double[] gcj2WGS(double glat,double glon){
            double[] latlon  = new double[2];
            if (outOfChina(glat, glon)){
                latlon[0] = glat;
                latlon[1] = glon;
               return latlon;
             }
            double[] deltaD =  delta(glat,glon);
            latlon[0] = glat - deltaD[0];
            latlon[1] = glon - deltaD[1];
            return latlon;
        }
       //GCJ02=>WGS84   火星坐标系=>地球坐标系（精确）
        public static double[] gcj2WGSExactly(double gcjLat,double gcjLon){
             double initDelta = 0.01;
             double threshold = 0.000000001;
             double dLat = initDelta, dLon = initDelta;
             double mLat = gcjLat - dLat, mLon = gcjLon - dLon;
             double pLat = gcjLat + dLat, pLon = gcjLon + dLon;
             double wgsLat, wgsLon, i = 0;
             while (true) {
                 wgsLat = (mLat + pLat) / 2;
                 wgsLon = (mLon + pLon) / 2;
                 double[] tmp = wgs2GCJ(wgsLat, wgsLon);
                 dLat = tmp[0] - gcjLat;
                 dLon = tmp[1] - gcjLon;
                 if ((Math.abs(dLat) < threshold) && (Math.abs(dLon) < threshold))
                     break;

                 if (dLat > 0) pLat = wgsLat; else mLat = wgsLat;
                 if (dLon > 0) pLon = wgsLon; else mLon = wgsLon;

                 if (++i > 10000) break;
             }
             double[] latlon = new double[2];
             latlon[0] = wgsLat;
             latlon[1] = wgsLon;
             return latlon;
        }

        //两点距离
        public static double distance(double latA, double logA, double latB,double  logB){
            int earthR = 6371000;
            double x = Math.cos(latA*Math.PI/180) * Math.cos(latB*Math.PI/180) * Math.cos((logA-logB)*Math.PI/180);
            double y = Math.sin(latA*Math.PI/180) * Math.sin(latB*Math.PI/180);
            double s = x + y;
            if (s > 1)
                s = 1;
            if (s < -1)
                s = -1;
            double alpha = Math.acos(s);
            double distance = alpha * earthR;
            return distance;
        }

        public static double[] delta(double wgLat, double wgLon){
             double[] latlng  = new double[2];
             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 - OFFSET * magic * magic;
             double sqrtMagic = Math.sqrt(magic);
             dLat = (dLat * 180.0) / ((AXIS * (1 - OFFSET)) / (magic * sqrtMagic) * PI);
             dLon = (dLon * 180.0) / (AXIS / sqrtMagic * Math.cos(radLat) * PI);
             latlng[0] =dLat;
             latlng[1] =dLon;
                return latlng;
        }

        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;
        }  

        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;
        }
}