关于GPS与GIS的一些思考

有些偏到河里可能与  丢失精度有关

这个是很早就认定的事情，百度也会出来一堆结果的。
1.代码纠偏 2.查询纠偏数据库。
第１种方便些。

可能中国的地图是不会准了。。。

http://blog.csdn.net/gatr/article/details/9569189

巧妙解决百度地图加偏纠偏问题

/**
 * 各地图API坐标系统比较与转换;
 * WGS84坐标系：即地球坐标系，国际上通用的坐标系。设备一般包含GPS芯片或者北斗芯片获取的经纬度为WGS84地理坐标系,
 * 谷歌地图采用的是WGS84地理坐标系（中国范围除外）;
 * GCJ02坐标系：即火星坐标系，是由中国国家测绘局制订的地理信息系统的坐标系统。由WGS84坐标系经加密后的坐标系。
 * 谷歌中国地图和搜搜中国地图采用的是GCJ02地理坐标系; BD09坐标系：即百度坐标系，GCJ02坐标系经加密后的坐标系;
 * 搜狗坐标系、图吧坐标系等，估计也是在GCJ02基础上加密而成的。 chenhua
 */
public class PositionUtil {

    public static final String BAIDU_LBS_TYPE = "bd09ll";

    public static double pi = 3.1415926535897932384626;
    public static double a = 6378245.0;
    public static double ee = 0.00669342162296594323;

    /**
     * 84 to 火星坐标系 (GCJ-02) World Geodetic System ==> Mars Geodetic System
     *
     * @param lat
     * @param lon
     * @return
     */
    public static Gps gps84_To_Gcj02(double lat, double lon) {
        if (outOfChina(lat, lon)) {
            return null;
        }
        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 Gps(mgLat, mgLon);
    }

    /**
     * * 火星坐标系 (GCJ-02) to 84 * * @param lon * @param lat * @return
     */
    public static Gps gcj_To_Gps84(double lat, double lon) {
        Gps gps = transform(lat, lon);
        double lontitude = lon * 2 - gps.getWgLon();
        double latitude = lat * 2 - gps.getWgLat();
        return new Gps(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 gg_lat
     * @param gg_lon
     */
    public static Gps gcj02_To_Bd09(double gg_lat, double gg_lon) {
        double x = gg_lon, y = gg_lat;
        double z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * pi);
        double theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * pi);
        double bd_lon = z * Math.cos(theta) + 0.0065;
        double bd_lat = z * Math.sin(theta) + 0.006;
        return new Gps(bd_lat, bd_lon);
    }

    /**
     * * 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 Gps bd09_To_Gcj02(double bd_lat, double bd_lon) {
        double x = bd_lon - 0.0065, y = bd_lat - 0.006;
        double z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * pi);
        double theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * pi);
        double gg_lon = z * Math.cos(theta);
        double gg_lat = z * Math.sin(theta);
        return new Gps(gg_lat, gg_lon);
    }

    /**
     * (BD-09)-->84
     *
     * @param bd_lat
     * @param bd_lon
     * @return
     */
    public static Gps bd09_To_Gps84(double bd_lat, double bd_lon) {

        Gps gcj02 = PositionUtil.bd09_To_Gcj02(bd_lat, bd_lon);
        Gps map84 = PositionUtil.gcj_To_Gps84(gcj02.getWgLat(),
                gcj02.getWgLon());
        return map84;

    }

    /**
     * 84-->(BD-09)
     *
     * @param lat
     * @param lon
     * @return
     */
    public static Gps gps84_To_Bd09(double lat, double lon) {

        Gps gcj02 = PositionUtil.gps84_To_Gcj02(lat, lon);
        Gps bd09 = PositionUtil.gcj02_To_Bd09(gcj02.getWgLat(),
                gcj02.getWgLon());
        return bd09;

    }

    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 Gps transform(double lat, double lon) {
        if (outOfChina(lat, lon)) {
            return new Gps(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 Gps(mgLat, mgLon);
    }

    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;
    }

    /**
     * 计算两点之间的距离 单位千米
     *
     * @param lon1 longitude1
     * @param lat2 latitude1
     * @param lon2 longitude2
     * @param lat2 latitude2
     * @return 距离
     */
    public static float calculateLineDistance(double lon1, double lat1, double lon2, double lat2) {
        double d2 = lon1;
        double d3 = lat1;
        double d4 = lon2;
        double d5 = lat2;

        d2 *= 0.01745329251994329D;
        d3 *= 0.01745329251994329D;
        d4 *= 0.01745329251994329D;
        d5 *= 0.01745329251994329D;
        double d6 = Math.sin(d2);
        double d7 = Math.sin(d3);
        double d8 = Math.cos(d2);
        double d9 = Math.cos(d3);
        double d10 = Math.sin(d4);
        double d11 = Math.sin(d5);
        double d12 = Math.cos(d4);
        double d13 = Math.cos(d5);
        double[] arrayOfDouble1 = new double[3];
        double[] arrayOfDouble2 = new double[3];
        arrayOfDouble1[0] = (d9 * d8);
        arrayOfDouble1[1] = (d9 * d6);
        arrayOfDouble1[2] = d7;
        arrayOfDouble2[0] = (d13 * d12);
        arrayOfDouble2[1] = (d13 * d10);
        arrayOfDouble2[2] = d11;
        double d14 = Math.sqrt((arrayOfDouble1[0] - arrayOfDouble2[0]) * (arrayOfDouble1[0] - arrayOfDouble2[0]) + (arrayOfDouble1[1] - arrayOfDouble2[1]) * (arrayOfDouble1[1] - arrayOfDouble2[1]) + (arrayOfDouble1[2] - arrayOfDouble2[2]) * (arrayOfDouble1[2] - arrayOfDouble2[2]));

        return (float) (Math.asin(d14 / 2.0D) * 1.27420015798544E7D);
    }

    public static void main(String[] args) {

        // 北斗芯片获取的经纬度为WGS84地理坐标 31.426896,119.496145

        //113.37122,23.102846
        Gps bdGps = PositionUtil.gcj_To_Gps84(31.426896,119.496145);
        System.out.println(bdGps.getWgLat() + ", " + bdGps.getWgLon());



    }

    public static class Gps {

        private double wgLat;
        private double wgLon;

        public Gps(double wgLat, double wgLon) {
            setWgLat(wgLat);
            setWgLon(wgLon);
        }

        public double getWgLat() {
            return wgLat;
        }

        public void setWgLat(double wgLat) {
            this.wgLat = wgLat;
        }

        public double getWgLon() {
            return wgLon;
        }

        public void setWgLon(double wgLon) {
            this.wgLon = wgLon;
        }

        @Override
        public String toString() {
            return wgLat + "," + wgLon;
        }
    }
}