常用坐标系介绍
WGS-84(GPS)
国际标准，一般从国际标准的GPS设备获取的坐标都是WGS-84，以及国际地图提供商使用的坐标系。
GCJ-02
中国标准，国测局02年发布的坐标系。又称“火星坐标”。在中国，必须至少使用“GCJ-02”对地理位置进行首次加密。比如谷歌中国、高德、腾讯都在用这个坐标系。
BD-09
百度标准，在“GCJ-02”的基础上进行二次加密。
北斗定位系统坐标
如果有对接过北斗定位系统的小伙伴可能会发现一个问题，北斗坐标经纬度好像都被乘了100？
$GNRMC,083735.000,A,2429.53531,N,11810.78036,E,0.54,171.11,190621,A*7E
这个，就是我们北斗定位系统接收到的坐标值，可以发现，北纬是2429.53531，东经是11810.78036，倘若我们直接将这个经纬度除100，北纬24.2953531，东经118.1078036，扔到百度或者高德地图中，我们会发现，坐标偏移的离谱。
高德地图定位：
百度地图定位：
可以发现，两者的距离都偏移了几十公里，这个原因就在于，国内，无论是高德还是百度，它们所使用的经纬度值，都是经过加密之后的值，而不是直接用GPS的实际经纬度来定位的，因此，我们如果想要将北斗定位系统的坐标系，用于商业地图上，则需要将它经过对应的加密转换处理才能够正确的使用。
坐标系的相互转换
首先，要强调一点，其实我们北斗定位的坐标系值并不是简单的100倍关系，而是需要做一次度分秒的转换的。则我们获取的北斗坐标值，北纬2429.53531，东经11810.78036，需要做如下计算：24+（29.53531/60）≈ 24.49225517 118+（10.78036/60）≈118.17967267
这两个值才是我们应该带入转换公式的坐标值，如果直接用100倍关系的值去转换，定位一样会偏差
接着上代码
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;/*** 北斗坐标系度分秒计算* @param msg* @return*/public static GPS str_To_Gps84(String msg){double lat = 0;double lon = 0;String[] split = msg.split(",");if (split[4].equals("N") || split[4].equals("S")){int i = split[3].indexOf(".");String latInt = split[3].substring(0, i - 2);String latDec = split[3].substring(i-2);int i1 = split[5].indexOf(".");String lonInt = split[5].substring(0, i1-2);String lonDec = split[5].substring(i1-2);lat = Integer.parseInt(latInt) + Double.parseDouble(latDec)/60;lon = Integer.parseInt(lonInt) + Double.parseDouble(lonDec)/60;System.out.println("latInt = "+ latInt);System.out.println("latDec = "+ latDec);System.out.println("lonInt = "+ lonInt);System.out.println("lonDec = "+ lonDec);System.out.println("lat = "+ lat);System.out.println("lon = "+ lon);} else {return null;}return new GPS(lat,lon);}/*** 84 to 火星坐标系 (GCJ-02)* @param lat* @param lon*/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.getLon();double latitude = lat * 2 - gps.getLat();return new GPS(latitude, lontitude);}/*** 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);}/*** * 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;double 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 = bd09_To_Gcj02(bd_lat, bd_lon);GPS map84 = gcj_To_Gps84(gcj02.getLat(),gcj02.getLon());return map84;}/*** is or not outOfChina* @param lat* @param lon* @return*/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;}//求两坐标距离public static double distance(double lonA,double latA,double lonB,double latB){int earthR = 6371000;double x = Math.cos(latA * PI / 180.) * Math.cos(latB * PI / 180.) * Math.cos((lonA - lonB) * PI / 180);double y = Math.sin(latA * PI / 180.) * Math.sin(latB * 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;}//重载，根据两个点求距离public static double distance(GPS p1,GPS p2){return distance(p1.getLon(), p1.getLat(), p2.getLon(), p2.getLat());}
高德地图用的GCJ-02坐标系转换结果：
public CommonResult test() {String msg = "$GNRMC,083735.000,A,2429.53531,N,11810.78036,E,0.54,171.11,190621,,,A*7E";GPS gps2 = GPSConverterUtils.str_To_Gps84(msg);GPS gps = GPSConverterUtils.gps84_To_Gcj02(gps2.getLat(), gps2.getLon());return CommonResult.success(gps);}
"lat": 24.489503175446604, "lon": 118.18449589009587
可以看到转换过来后的坐标系，精确定位到了我们办公楼
百度坐标系的BD-09坐标系转换结果：
public CommonResult test() {String msg = "$GNRMC,083735.000,A,2429.53531,N,11810.78036,E,0.54,171.11,190621,,,A*7E";GPS gps2 = GPSConverterUtils.str_To_Gps84(msg);GPS gps = GPSConverterUtils.gps84_To_Gcj02(gps2.getLat(), gps2.getLon());GPS gps1 = GPSConverterUtils.gcj02_To_Bd09(gps.getLat(), gps.getLon());return CommonResult.success(gps1);}
"lat": 24.49580387761381, "lon": 118.19095399371493
可以看到百度地图也精确的定位到了我们的办公楼
结论
谷歌地图那些，用的是WGS-84坐标系，北斗定位系统给到的坐标值要做一次度分秒的转换，转换后才是84坐标，像高德地图那些用的是GCJ-02火星坐标系，等于要先做一次GCJ-02加密，坐标系才能在高德地图用，百度地图则需要再做一次BD-09的加密
