地图坐标转换

问题来源

目前 IoT 领域各种智能设备都可以采集 GPS 数据，但是设备采集到的GPS都是 WGS-84 坐标系数据，在国内不能直接用于在地图上显示，需要进行一定转换。各地图工具都有坐标转换 API 可用，但是成千上万的 GPS 数据通过 API 转换是一件很消耗资源的事，所以需要提供一种离线转换的方式。

本人在项目中曾也用过 API 转换的方式，但是当设备数量一增加，在坐标转换这一个小功能上带来了巨大的资源开销，是一件很不划算事，因此想到利用算法替换 API 方式进行坐标转换。在查阅了一些资料和自己的整理后，进行了一下总结。

大地坐标系（WGS-84）

大地坐标系是大地测量中以参考椭球面为基准面建立起来的坐标系。地面点的位置用大地经度、大地纬度和大地高度表示。大地坐标系的确立包括选择一个椭球、对椭球进行定位和确定大地起算数据。

火星坐标系（GCJ-02）

是一种国家保密插件，也叫做加密插件或者加偏或者SM模组，其实就是对真实坐标系统进行人为的加偏处理，按照特殊的算法，将真实的坐标加密成虚假的坐标，而这个加偏并不是线性的加偏，所以各地的偏移情况都会有所不同。而加密后的坐标也常被人称为火星坐标系统。
所有的电子地图、导航设备，都需要加入国家保密插件。第一步，地图公司测绘地图，测绘完成后，送到国家测绘局，将真实坐标的电子地图，加密成“火星坐标”，这样的地图才是可以出版和发布的，然后才可以让GPS公司处理。第二步，所有的GPS公司，只要需要汽车导航的，需要用到导航电子地图的，都需要在软件中加入国家保密算法，将COM口读出来的真实的坐标信号，加密转换成国家要求的保密的坐标。这样，GPS导航仪和导航电子地图就可以完全匹配，GPS也就可以正常工作了。

百度坐标系（BD-09）

百度坐标对火星坐标系进行了一次加密，形成了百度坐标系。

具体实现

附上坐标转化详细 Java 版代码，Java 版本最低要求 Java 8
代码中也提供了两种判断 WGS-84 坐标点是否在国内的方法，一种是很粗略的判断，另一种较为精确，但沿海、国界周边地区可能会有误差，更高精度需要自行调整坐标点。

/**
 * 地图坐标转换
 *
 * @author Leaves
 * @version 1.0.0
 * @date 2017/9/24
 */
public class GpsCoordinateUtil {

    //private static final double PI = 3.1415926535897932384626433832795;
    private static final double PI = 3.14159265358979324;
    private static final double A = 6378245.0;
    private static final double EE = 0.00669342162296594323;

    /**
     * 地球坐标系 WGS-84 to 火星坐标系 GCJ-02
     *
     * @param latitude  纬度
     * @param longitude 经度
     * @return [纬度, 经度]
     */
    public static double[] calWGS84toGCJ02(double latitude, double longitude) {
        Point dev = calDev(latitude, longitude);
        double retLat = latitude + dev.getLatitude();
        double retLon = longitude + dev.getLongitude();
        return new double[]{retLat, retLon};
    }

    /**
     * 地球坐标系 WGS-84 to 百度坐标系 BD-09
     *
     * @param latitude  纬度
     * @param longitude 经度
     * @return [纬度, 经度]
     */
    public static double[] calWGS84toBD09(double latitude, double longitude) {
        Point dev = calDev(latitude, longitude);
        double retLat = latitude + dev.getLatitude();
        double retLon = longitude + dev.getLongitude();
        return calGCJ02toBD09(retLat, retLon);
    }

    /**
     * 火星坐标系 GCJ-02 to 地球坐标系 WGS-84
     *
     * @param latitude  纬度
     * @param longitude 经度
     * @return [纬度, 经度]
     */
    public static double[] calGCJ02toWGS84(double latitude, double longitude) {
        Point dev = calDev(latitude, longitude);
        double retLat = latitude - dev.getLatitude();
        double retLon = longitude - dev.getLongitude();
        dev = calDev(retLat, retLon);
        retLat = latitude - dev.getLatitude();
        retLon = longitude - dev.getLongitude();
        return new double[]{retLat, retLon};
    }

    /**
     * 百度坐标系 BD-09 to 地球坐标系 WGS-84
     *
     * @param latitude  纬度
     * @param longitude 经度
     * @return [纬度, 经度]
     */
    public static double[] calBD09toWGS84(double latitude, double longitude) {
        double[] gcj = calBD09toGCJ02(latitude, longitude);
        return calGCJ02toWGS84(gcj[0], gcj[1]);
    }

    private static Point calDev(double latitude, double longitude) {
        if (isOutOfChina(latitude, longitude, false)) {
            return new Point(0, 0);
        }
        double dLat = calLat(longitude - 105.0, latitude - 35.0);
        double dLon = calLon(longitude - 105.0, latitude - 35.0);
        double radLat = latitude / 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);
        return new Point(dLat, dLon);
    }

    private static double calLat(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 calLon(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;
    }

    /**
     * 火星坐标系 GCJ-02 to 百度坐标系 BD-09
     *
     * @param latitude  纬度
     * @param longitude 经度
     * @return [纬度, 经度]
     */
    public static double[] calGCJ02toBD09(double latitude, double longitude) {
        double x = longitude, y = latitude;
        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 retLat = z * Math.sin(theta) + 0.006;
        double retLon = z * Math.cos(theta) + 0.0065;
        return new double[]{retLat, retLon};
    }

    /**
     * 百度坐标系 BD-09 to 火星坐标系 GCJ-02
     *
     * @param latitude  纬度
     * @param longitude 经度
     * @return [纬度, 经度]
     */
    public static double[] calBD09toGCJ02(double latitude, double longitude) {
        double x = longitude - 0.0065, y = latitude - 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 retLat = z * Math.sin(theta);
        double retLon = z * Math.cos(theta);
        return new double[]{retLat, retLon};
    }

    /**
     * 判断坐标是否在国内
     *
     * @param latitude
     * @param longitude
     * @param precision 是否精确判断范围
     * @return true 在国外，false 在国内
     */
    private static boolean isOutOfChina(double latitude, double longitude, boolean precision) {
        if (precision) {
            return CHINA_POLYGON.stream().noneMatch(point -> pointInPolygon(point, latitude, longitude));
        } else {
            if (longitude < 72.004 || longitude > 137.8347) {
                return true;
            }
            if (latitude < 0.8293 || latitude > 55.8271) {
                return true;
            }
            return false;
        }
    }

    /**
     * 检查坐标点是否在多边形区域内
     *
     * @param polygon   多边形
     * @param latitude  纬度
     * @param longitude 经度
     * @return true 在多边形区域内，false 在多边形区域外
     */
    private static boolean pointInPolygon(Point[] polygon, double latitude, double longitude) {
        int i, j = polygon.length - 1;
        boolean oddNodes = false;
        for (i = 0; i < polygon.length; i++) {
            if ((polygon[i].getLatitude() < latitude && polygon[j].getLatitude() >= latitude
                    || polygon[j].getLatitude() < latitude && polygon[i].getLatitude() >= latitude)
                    && (polygon[i].getLongitude() <= longitude || polygon[j].getLongitude() <= longitude)) {
                if (polygon[i].getLongitude()
                        + (latitude - polygon[i].getLatitude()) / (polygon[j].getLatitude() - polygon[i].getLatitude())
                        * (polygon[j].getLongitude() - polygon[i].getLongitude())
                        < longitude) {
                    oddNodes = !oddNodes;
                }
            }
            j = i;
        }
        return oddNodes;
    }

    static class Point {
        private double longitude;
        private double latitude;

        Point(double latitude, double longitude) {
            this.longitude = longitude;
            this.latitude = latitude;
        }

        public double getLongitude() {
            return longitude;
        }

        public void setLongitude(double longitude) {
            this.longitude = longitude;
        }

        public double getLatitude() {
            return latitude;
        }

        public void setLatitude(double latitude) {
            this.latitude = latitude;
        }

        @Override
        public String toString() {
            return longitude + "," + latitude;
        }
    }

    //region 中国行政边界的WGS84坐标数据
    //Mainland
    private static final Point[] MAINLAND = new Point[]{
            new Point(27.32083, 88.91693),
            new Point(27.54243, 88.76464),
            new Point(28.00805, 88.83575),
            new Point(28.1168, 88.62435),
            new Point(27.86605, 88.14279),
            new Point(27.82305, 87.19275),
            new Point(28.11166, 86.69527),
            new Point(27.90888, 86.45137),
            new Point(28.15805, 86.19769),
            new Point(27.88625, 86.0054),
            new Point(28.27916, 85.72137),
            new Point(28.30666, 85.11095),
            new Point(28.59104, 85.19518),
            new Point(28.54444, 84.84665),
            new Point(28.73402, 84.48623),
            new Point(29.26097, 84.11651),
            new Point(29.18902, 83.5479),
            new Point(29.63166, 83.19109),
            new Point(30.06923, 82.17525),
            new Point(30.33444, 82.11123),
            new Point(30.385, 81.42623),
            new Point(30.01194, 81.23221),
            new Point(30.20435, 81.02536),
            new Point(30.57552, 80.207),
            new Point(30.73374, 80.25423),
            new Point(30.96583, 79.86304),
            new Point(30.95708, 79.55429),
            new Point(31.43729, 79.08082),
            new Point(31.30895, 78.76825),
            new Point(31.96847, 78.77075),
            new Point(32.24304, 78.47594),
            new Point(32.5561, 78.40595),
            new Point(32.63902, 78.74623),
            new Point(32.35083, 78.9711),
            new Point(32.75666, 79.52874),
            new Point(33.09944, 79.37511),
            new Point(33.42863, 78.93623),
            new Point(33.52041, 78.81387),
            new Point(34.06833, 78.73581),
            new Point(34.35001, 78.98535),
            new Point(34.6118, 78.33707),
            new Point(35.28069, 78.02305),
            new Point(35.49902, 78.0718),
            new Point(35.50133, 77.82393),
            new Point(35.6125, 76.89526),
            new Point(35.90665, 76.55304),
            new Point(35.81458, 76.18061),
            new Point(36.07082, 75.92887),
            new Point(36.23751, 76.04166),
            new Point(36.66343, 75.85984),
            new Point(36.73169, 75.45179),
            new Point(36.91156, 75.39902),
            new Point(36.99719, 75.14787),
            new Point(37.02782, 74.56543),
            new Point(37.17, 74.39089),
            new Point(37.23733, 74.91574),
            new Point(37.40659, 75.18748),
            new Point(37.65243, 74.9036),
            new Point(38.47256, 74.85442),
            new Point(38.67438, 74.35471),
            new Point(38.61271, 73.81401),
            new Point(38.88653, 73.70818),
            new Point(38.97256, 73.85235),
            new Point(39.23569, 73.62005),
            new Point(39.45483, 73.65569),
            new Point(39.59965, 73.95471),
            new Point(39.76896, 73.8429),
            new Point(40.04202, 73.99096),
            new Point(40.32792, 74.88089),
            new Point(40.51723, 74.8588),
            new Point(40.45042, 75.23394),
            new Point(40.64452, 75.58284),
            new Point(40.298, 75.70374),
            new Point(40.35324, 76.3344),
            new Point(41.01258, 76.87067),
            new Point(41.04079, 78.08083),
            new Point(41.39286, 78.39554),
            new Point(42.03954, 80.24513),
            new Point(42.19622, 80.23402),
            new Point(42.63245, 80.15804),
            new Point(42.81565, 80.25796),
            new Point(42.88545, 80.57226),
            new Point(43.02906, 80.38405),
            new Point(43.1683, 80.81526),
            new Point(44.11378, 80.36887),
            new Point(44.6358, 80.38499),
            new Point(44.73408, 80.51589),
            new Point(44.90282, 79.87106),
            new Point(45.3497, 81.67928),
            new Point(45.15748, 81.94803),
            new Point(45.13303, 82.56638),
            new Point(45.43581, 82.64624),
            new Point(45.5831, 82.32179),
            new Point(47.20061, 83.03443),
            new Point(46.97332, 83.93026),
            new Point(46.99361, 84.67804),
            new Point(46.8277, 84.80318),
            new Point(47.0591, 85.52257),
            new Point(47.26221, 85.70139),
            new Point(47.93721, 85.53707),
            new Point(48.39333, 85.76596),
            new Point(48.54277, 86.59791),
            new Point(49.1102, 86.87602),
            new Point(49.09262, 87.34821),
            new Point(49.17295, 87.8407),
            new Point(48.98304, 87.89291),
            new Point(48.88103, 87.7611),
            new Point(48.73499, 88.05942),
            new Point(48.56541, 87.99194),
            new Point(48.40582, 88.51679),
            new Point(48.21193, 88.61179),
            new Point(47.99374, 89.08514),
            new Point(47.88791, 90.07096),
            new Point(46.95221, 90.9136),
            new Point(46.57735, 91.07027),
            new Point(46.29694, 90.92151),
            new Point(46.01735, 91.02651),
            new Point(45.57972, 90.68193),
            new Point(45.25305, 90.89694),
            new Point(45.07729, 91.56088),
            new Point(44.95721, 93.5547),
            new Point(44.35499, 94.71735),
            new Point(44.29416, 95.41061),
            new Point(44.01937, 95.34109),
            new Point(43.99311, 95.53339),
            new Point(43.28388, 95.87901),
            new Point(42.73499, 96.38206),
            new Point(42.79583, 97.1654),
            new Point(42.57194, 99.51012),
            new Point(42.67707, 100.8425),
            new Point(42.50972, 101.8147),
            new Point(42.23333, 102.0772),
            new Point(41.88721, 103.4164),
            new Point(41.87721, 104.5267),
            new Point(41.67068, 104.5237),
            new Point(41.58666, 105.0065),
            new Point(42.46624, 107.4758),
            new Point(42.42999, 109.3107),
            new Point(42.64576, 110.1064),
            new Point(43.31694, 110.9897),
            new Point(43.69221, 111.9583),
            new Point(44.37527, 111.4214),
            new Point(45.04944, 111.873),
            new Point(45.08055, 112.4272),
            new Point(44.8461, 112.853),
            new Point(44.74527, 113.638),
            new Point(45.38943, 114.5453),
            new Point(45.4586, 115.7019),
            new Point(45.72193, 116.2104),
            new Point(46.29583, 116.5855),
            new Point(46.41888, 117.3755),
            new Point(46.57069, 117.425),
            new Point(46.53645, 117.8455),
            new Point(46.73638, 118.3147),
            new Point(46.59895, 119.7068),
            new Point(46.71513, 119.9315),
            new Point(46.90221, 119.9225),
            new Point(47.66499, 119.125),
            new Point(47.99475, 118.5393),
            new Point(48.01125, 117.8046),
            new Point(47.65741, 117.3827),
            new Point(47.88805, 116.8747),
            new Point(47.87819, 116.2624),
            new Point(47.69186, 115.9231),
            new Point(47.91749, 115.5944),
            new Point(48.14353, 115.5491),
            new Point(48.25249, 115.8358),
            new Point(48.52055, 115.8111),
            new Point(49.83047, 116.7114),
            new Point(49.52058, 117.8747),
            new Point(49.92263, 118.5746),
            new Point(50.09631, 119.321),
            new Point(50.33028, 119.36),
            new Point(50.39027, 119.1386),
            new Point(51.62083, 120.0641),
            new Point(52.115, 120.7767),
            new Point(52.34423, 120.6259),
            new Point(52.54267, 120.7122),
            new Point(52.58805, 120.0819),
            new Point(52.76819, 120.0314),
            new Point(53.26374, 120.8307),
            new Point(53.54361, 123.6147),
            new Point(53.18832, 124.4933),
            new Point(53.05027, 125.62),
            new Point(52.8752, 125.6573),
            new Point(52.75722, 126.0968),
            new Point(52.5761, 125.9943),
            new Point(52.12694, 126.555),
            new Point(51.99437, 126.4412),
            new Point(51.38138, 126.9139),
            new Point(51.26555, 126.8176),
            new Point(51.31923, 126.9689),
            new Point(51.05825, 126.9331),
            new Point(50.74138, 127.2919),
            new Point(50.31472, 127.334),
            new Point(50.20856, 127.5861),
            new Point(49.80588, 127.515),
            new Point(49.58665, 127.838),
            new Point(49.58443, 128.7119),
            new Point(49.34676, 129.1118),
            new Point(49.4158, 129.4902),
            new Point(48.86464, 130.2246),
            new Point(48.86041, 130.674),
            new Point(48.60576, 130.5236),
            new Point(48.3268, 130.824),
            new Point(48.10839, 130.6598),
            new Point(47.68721, 130.9922),
            new Point(47.71027, 132.5211),
            new Point(48.09888, 133.0827),
            new Point(48.06888, 133.4843),
            new Point(48.39112, 134.4153),
            new Point(48.26713, 134.7408),
            new Point(47.99207, 134.5576),
            new Point(47.70027, 134.7608),
            new Point(47.32333, 134.1825),
            new Point(46.64017, 133.9977),
            new Point(46.47888, 133.8472),
            new Point(46.25363, 133.9016),
            new Point(45.82347, 133.4761),
            new Point(45.62458, 133.4702),
            new Point(45.45083, 133.1491),
            new Point(45.05694, 133.0253),
            new Point(45.34582, 131.8684),
            new Point(44.97388, 131.4691),
            new Point(44.83649, 130.953),
            new Point(44.05193, 131.298),
            new Point(43.53624, 131.1912),
            new Point(43.38958, 131.3104),
            new Point(42.91645, 131.1285),
            new Point(42.74485, 130.4327),
            new Point(42.42186, 130.6044),
            new Point(42.71416, 130.2468),
            new Point(42.88794, 130.2514),
            new Point(43.00457, 129.9046),
            new Point(42.43582, 129.6955),
            new Point(42.44624, 129.3493),
            new Point(42.02736, 128.9269),
            new Point(42.00124, 128.0566),
            new Point(41.58284, 128.3002),
            new Point(41.38124, 128.1529),
            new Point(41.47249, 127.2708),
            new Point(41.79222, 126.9047),
            new Point(41.61176, 126.5661),
            new Point(40.89694, 126.0118),
            new Point(40.47037, 124.8851),
            new Point(40.09362, 124.3736),
            new Point(39.82777, 124.128),
            new Point(39.8143, 123.2422),
            new Point(39.67388, 123.2167),
            new Point(38.99638, 121.648),
            new Point(38.8611, 121.6982),
            new Point(38.71909, 121.1873),
            new Point(38.91221, 121.0887),
            new Point(39.09013, 121.6794),
            new Point(39.2186, 121.5994),
            new Point(39.35166, 121.7511),
            new Point(39.52847, 121.2283),
            new Point(39.62322, 121.533),
            new Point(39.81138, 121.4683),
            new Point(40.00305, 121.881),
            new Point(40.50562, 122.2987),
            new Point(40.73874, 122.0521),
            new Point(40.92194, 121.1775),
            new Point(40.1961, 120.4468),
            new Point(39.87242, 119.5264),
            new Point(39.15693, 118.9715),
            new Point(39.04083, 118.3273),
            new Point(39.19846, 117.889),
            new Point(38.67555, 117.5364),
            new Point(38.38666, 117.6722),
            new Point(38.16721, 118.0281),
            new Point(38.1529, 118.8378),
            new Point(37.87832, 119.0355),
            new Point(37.30054, 118.9566),
            new Point(37.14361, 119.2328),
            new Point(37.15138, 119.7672),
            new Point(37.35228, 119.8529),
            new Point(37.83499, 120.7371),
            new Point(37.42458, 121.58),
            new Point(37.55256, 122.1282),
            new Point(37.41833, 122.1814),
            new Point(37.39624, 122.5586),
            new Point(37.20999, 122.5972),
            new Point(37.02583, 122.4005),
            new Point(37.01978, 122.5392),
            new Point(36.89361, 122.5047),
            new Point(36.84298, 122.1923),
            new Point(37.00027, 121.9566),
            new Point(36.75889, 121.5944),
            new Point(36.61666, 120.7764),
            new Point(36.52638, 120.96),
            new Point(36.37582, 120.8753),
            new Point(36.42277, 120.7062),
            new Point(36.14075, 120.6956),
            new Point(36.0419, 120.3436),
            new Point(36.26345, 120.3078),
            new Point(36.19998, 120.0889),
            new Point(35.95943, 120.2378),
            new Point(35.57893, 119.6475),
            new Point(34.88499, 119.1761),
            new Point(34.31145, 120.2487),
            new Point(32.97499, 120.8858),
            new Point(32.63889, 120.8375),
            new Point(32.42958, 121.3348),
            new Point(32.11333, 121.4412),
            new Point(32.02166, 121.7066),
            new Point(31.67833, 121.8275),
            new Point(31.86639, 120.9444),
            new Point(32.09361, 120.6019),
            new Point(31.94555, 120.099),
            new Point(32.30638, 119.8267),
            new Point(32.26277, 119.6317),
            new Point(31.90388, 120.1364),
            new Point(31.98833, 120.7026),
            new Point(31.81944, 120.7196),
            new Point(31.30889, 121.6681),
            new Point(30.97986, 121.8828),
            new Point(30.85305, 121.8469),
            new Point(30.56889, 120.9915),
            new Point(30.33555, 120.8144),
            new Point(30.39298, 120.4586),
            new Point(30.19694, 120.15),
            new Point(30.31027, 120.5082),
            new Point(30.06465, 120.7916),
            new Point(30.30458, 121.2808),
            new Point(29.96305, 121.6778),
            new Point(29.88211, 122.1196),
            new Point(29.51167, 121.4483),
            new Point(29.58916, 121.9744),
            new Point(29.19527, 121.9336),
            new Point(29.18388, 121.8119),
            new Point(29.37236, 121.7969),
            new Point(29.19729, 121.7444),
            new Point(29.29111, 121.5611),
            new Point(29.1634, 121.4135),
            new Point(29.02194, 121.6914),
            new Point(28.9359, 121.4908),
            new Point(28.72798, 121.6113),
            new Point(28.84215, 121.1464),
            new Point(28.66993, 121.4844),
            new Point(28.34722, 121.6417),
            new Point(28.13889, 121.3419),
            new Point(28.38277, 121.1651),
            new Point(27.98222, 120.9353),
            new Point(28.07944, 120.5908),
            new Point(27.87229, 120.84),
            new Point(27.59319, 120.5812),
            new Point(27.45083, 120.6655),
            new Point(27.20777, 120.5075),
            new Point(27.28278, 120.1896),
            new Point(27.14764, 120.4211),
            new Point(26.89805, 120.0332),
            new Point(26.64465, 120.128),
            new Point(26.51778, 119.8603),
            new Point(26.78823, 120.0733),
            new Point(26.64888, 119.8668),
            new Point(26.79611, 119.7879),
            new Point(26.75625, 119.5503),
            new Point(26.44222, 119.8204),
            new Point(26.47388, 119.5775),
            new Point(26.33861, 119.658),
            new Point(26.36777, 119.9489),
            new Point(25.99694, 119.4253),
            new Point(26.14041, 119.0975),
            new Point(25.93788, 119.354),
            new Point(25.99069, 119.7058),
            new Point(25.67996, 119.5807),
            new Point(25.68222, 119.4522),
            new Point(25.35333, 119.6454),
            new Point(25.60649, 119.3149),
            new Point(25.42097, 119.1053),
            new Point(25.25319, 119.3526),
            new Point(25.17208, 119.2726),
            new Point(25.2426, 118.8749),
            new Point(24.97194, 118.9866),
            new Point(24.88291, 118.5729),
            new Point(24.75673, 118.7631),
            new Point(24.52861, 118.5953),
            new Point(24.53638, 118.2397),
            new Point(24.68194, 118.1688),
            new Point(24.44024, 118.0199),
            new Point(24.46019, 117.7947),
            new Point(24.25875, 118.1237),
            new Point(23.62437, 117.1957),
            new Point(23.65919, 116.9179),
            new Point(23.355, 116.7603),
            new Point(23.42024, 116.5322),
            new Point(23.23666, 116.7871),
            new Point(23.21083, 116.5139),
            new Point(22.93902, 116.4817),
            new Point(22.73916, 115.7978),
            new Point(22.88416, 115.6403),
            new Point(22.65889, 115.5367),
            new Point(22.80833, 115.1614),
            new Point(22.70277, 114.8889),
            new Point(22.53305, 114.8722),
            new Point(22.64027, 114.718),
            new Point(22.81402, 114.7782),
            new Point(22.69972, 114.5208),
            new Point(22.50423, 114.6136),
            new Point(22.55004, 114.2223),
            new Point(22.42993, 114.3885),
            new Point(22.26056, 114.2961),
            new Point(22.36736, 113.9056),
            new Point(22.50874, 114.0337),
            new Point(22.47444, 113.8608),
            new Point(22.83458, 113.606),
            new Point(23.05027, 113.5253),
            new Point(23.11724, 113.8219),
            new Point(23.05083, 113.4793),
            new Point(22.87986, 113.3629),
            new Point(22.54944, 113.5648),
            new Point(22.18701, 113.5527),
            new Point(22.56701, 113.1687),
            new Point(22.17965, 113.3868),
            new Point(22.04069, 113.2226),
            new Point(22.20485, 113.0848),
            new Point(21.8693, 112.94),
            new Point(21.96472, 112.824),
            new Point(21.70139, 112.2819),
            new Point(21.91611, 111.8921),
            new Point(21.75139, 111.9669),
            new Point(21.77819, 111.6762),
            new Point(21.61264, 111.7832),
            new Point(21.5268, 111.644),
            new Point(21.52528, 111.0285),
            new Point(21.21138, 110.5328),
            new Point(21.37322, 110.3944),
            new Point(20.84381, 110.1594),
            new Point(20.84083, 110.3755),
            new Point(20.64, 110.3239),
            new Point(20.48618, 110.5274),
            new Point(20.24611, 110.2789),
            new Point(20.2336, 109.9244),
            new Point(20.4318, 110.0069),
            new Point(20.92416, 109.6629),
            new Point(21.44694, 109.9411),
            new Point(21.50569, 109.6605),
            new Point(21.72333, 109.5733),
            new Point(21.49499, 109.5344),
            new Point(21.39666, 109.1428),
            new Point(21.58305, 109.1375),
            new Point(21.61611, 108.911),
            new Point(21.79889, 108.8702),
            new Point(21.59888, 108.7403),
            new Point(21.93562, 108.4692),
            new Point(21.59014, 108.5125),
            new Point(21.68999, 108.3336),
            new Point(21.51444, 108.2447),
            new Point(21.54241, 107.99),
            new Point(21.66694, 107.7831),
            new Point(21.60526, 107.3627),
            new Point(22.03083, 106.6933),
            new Point(22.45682, 106.5517),
            new Point(22.76389, 106.7875),
            new Point(22.86694, 106.7029),
            new Point(22.91253, 105.8771),
            new Point(23.32416, 105.3587),
            new Point(23.18027, 104.9075),
            new Point(22.81805, 104.7319),
            new Point(22.6875, 104.3747),
            new Point(22.79812, 104.1113),
            new Point(22.50387, 103.9687),
            new Point(22.78287, 103.6538),
            new Point(22.58436, 103.5224),
            new Point(22.79451, 103.3337),
            new Point(22.43652, 103.0304),
            new Point(22.77187, 102.4744),
            new Point(22.39629, 102.1407),
            new Point(22.49777, 101.7415),
            new Point(22.20916, 101.5744),
            new Point(21.83444, 101.7653),
            new Point(21.14451, 101.786),
            new Point(21.17687, 101.2919),
            new Point(21.57264, 101.1482),
            new Point(21.76903, 101.099),
            new Point(21.47694, 100.6397),
            new Point(21.43546, 100.2057),
            new Point(21.72555, 99.97763),
            new Point(22.05018, 99.95741),
            new Point(22.15592, 99.16785),
            new Point(22.93659, 99.56484),
            new Point(23.08204, 99.5113),
            new Point(23.18916, 98.92747),
            new Point(23.97076, 98.67991),
            new Point(24.16007, 98.89073),
            new Point(23.92999, 97.54762),
            new Point(24.26055, 97.7593),
            new Point(24.47666, 97.54305),
            new Point(24.73992, 97.55255),
            new Point(25.61527, 98.19109),
            new Point(25.56944, 98.36137),
            new Point(25.85597, 98.7104),
            new Point(26.12527, 98.56944),
            new Point(26.18472, 98.73109),
            new Point(26.79166, 98.77777),
            new Point(27.52972, 98.69699),
            new Point(27.6725, 98.45888),
            new Point(27.54014, 98.31992),
            new Point(28.14889, 98.14499),
            new Point(28.54652, 97.55887),
            new Point(28.22277, 97.34888),
            new Point(28.46749, 96.65387),
            new Point(28.35111, 96.40193),
            new Point(28.525, 96.34027),
            new Point(28.79569, 96.61373),
            new Point(29.05666, 96.47083),
            new Point(28.90138, 96.17532),
            new Point(29.05972, 96.14888),
            new Point(29.25757, 96.39172),
            new Point(29.46444, 96.08315),
            new Point(29.03527, 95.38777),
            new Point(29.33346, 94.64751),
            new Point(29.07348, 94.23456),
            new Point(28.6692, 93.96172),
            new Point(28.61876, 93.35194),
            new Point(28.3193, 93.22205),
            new Point(28.1419, 92.71044),
            new Point(27.86194, 92.54498),
            new Point(27.76472, 91.65776),
            new Point(27.945, 91.66277),
            new Point(28.08111, 91.30138),
            new Point(27.96999, 91.08693),
            new Point(28.07958, 90.3765),
            new Point(28.24257, 90.38898),
            new Point(28.32369, 89.99819),
            new Point(28.05777, 89.48749),
            new Point(27.32083, 88.91693)
    };

    //Taiwan
    private static final Point[] TAIWAN = new Point[]{
            new Point(25.13474, 121.4441),
            new Point(25.28361, 121.5632),
            new Point(25.00722, 122.0004),
            new Point(24.85028, 121.8182),
            new Point(24.47638, 121.8397),
            new Point(23.0875, 121.3556),
            new Point(21.92791, 120.7196),
            new Point(22.31277, 120.6103),
            new Point(22.54044, 120.3071),
            new Point(23.04437, 120.0539),
            new Point(23.61708, 120.1112),
            new Point(25.00166, 121.0017),
            new Point(25.13474, 121.4441)
    };

    //Hainan
    private static final Point[] HAINAN = new Point[]{
            new Point(19.52888, 110.855),
            new Point(19.16761, 110.4832),
            new Point(18.80083, 110.5255),
            new Point(18.3852, 110.0503),
            new Point(18.39152, 109.7594),
            new Point(18.19777, 109.7036),
            new Point(18.50562, 108.6871),
            new Point(19.28028, 108.6283),
            new Point(19.76, 109.2939),
            new Point(19.7236, 109.1653),
            new Point(19.89972, 109.2572),
            new Point(19.82861, 109.4658),
            new Point(19.99389, 109.6108),
            new Point(20.13361, 110.6655),
            new Point(19.97861, 110.9425),
            new Point(19.63829, 111.0215),
            new Point(19.52888, 110.855)
    };

    //Chongming
    private static final Point[] CHONGMING = new Point[]{
            new Point(31.80054, 121.2039),
            new Point(31.49972, 121.8736),
            new Point(31.53111, 121.5464),
            new Point(31.80054, 121.2039)
    };
    //endregion

    /**
     * 中国行政边界的WGS84坐标数据，
     * 光线投射算法 (Ray casting algorithm) 获得，
     * 沿海、国界周边地区可能会有误差，更高精度需要调整坐标点
     */
    private static final List<Point[]> CHINA_POLYGON = new ArrayList<>();

    static {
        CHINA_POLYGON.add(MAINLAND);
        CHINA_POLYGON.add(TAIWAN);
        CHINA_POLYGON.add(HAINAN);
        CHINA_POLYGON.add(CHONGMING);
    }

    public static void main(String[] args) {
        // WGS84坐标: 30.256676, 120.149987
        Point gps = new Point(30.256676, 120.149987);
        System.out.println("WGS84          : " + gps);

        double[] wgsToGcj = calWGS84toGCJ02(gps.getLatitude(), gps.getLongitude());
        System.out.println("WGS84 -> GCJ02 : " + wgsToGcj[1] + "," + wgsToGcj[0]);

        double[] wgsToBd = calWGS84toBD09(gps.getLatitude(), gps.getLongitude());
        System.out.println("WGS84 -> BD09  : " + wgsToBd[1] + "," + wgsToBd[0]);

        double[] gcjToWgs = calGCJ02toWGS84(wgsToGcj[0], wgsToGcj[1]);
        System.out.println("GCJ02 -> WGS84 : " + gcjToWgs[1] + "," + gcjToWgs[0]);

        double[] bdToWgs = calBD09toWGS84(wgsToBd[0], wgsToBd[1]);
        System.out.println("BD09  -> WGS84 : " + bdToWgs[1] + "," + bdToWgs[0]);

        double[] gcjToBd = calGCJ02toBD09(wgsToGcj[0], wgsToGcj[1]);
        System.out.println("GCJ02 -> BD09  : " + gcjToBd[1] + "," + gcjToBd[0]);

        double[] bdToGcj = calBD09toGCJ02(wgsToBd[0], wgsToBd[1]);
        System.out.println("BD09  -> GCJ02 : " + bdToGcj[1] + "," + bdToGcj[0]);

        Long start = System.nanoTime();
        System.out.println("OutOfChina     : " + isOutOfChina(30.256676, 120.149987, true) + ", " + (System.nanoTime() - start) + " ns");
    }
}

参考与感谢

Darel Rex Finley : Point-In-Polygon Algorithm
Aimeast : 【WP7】判断GPS坐标是否在中国