关于各种地图（百度、高德等等）的坐标类型以及相互转换

bd09ll  表示百度经纬度坐标，

gcj02   表示经过国测局加密的坐标，

wgs84   表示gps获取的坐标。

其中最坑的是百度的坐标，百度坐标在原有的基础上自己做了一层加密，也就是bd0911，而且理论上来讲这个加密的过程是不可逆的，

百度地图api置提供了其他的坐标类型转换成百度坐标的方法，但是这个过程并不可逆，但是确实被我找到一种办法进行转换，直接上代码

/**
*
* 将百度坐标转换成GPS坐标工具类
* @author fuys
*
*/
public class GlobalTool {
public final static double a = 6378245.0;
public final static double ee = 0.00669342162296594323;

// 判断坐标是否在中国
public static boolean outOfChina(BDLocation bdLocation) {
double lat = bdLocation.getLatitude();
double lon = bdLocation.getLongitude();
if (lon < 72.004 || lon > 137.8347)
return true;
if (lat < 0.8293 || lat > 55.8271)
return true;
if ((119.962 < lon && lon < 121.750) && (21.586 < lat && lat < 25.463))
return true;

return false;
}

public final static double x_pi = 3.14159265358979324 * 3000.0 / 180.0;

public static BDLocation BAIDU_to_WGS84(BDLocation bdLocation) {
if (outOfChina(bdLocation)) {
return bdLocation;
}
double x = bdLocation.getLongitude() - 0.0065;
double y = bdLocation.getLatitude() - 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);
bdLocation.setLongitude(z * Math.cos(theta));
bdLocation.setLatitude(z * Math.sin(theta));
return GCJ02_to_WGS84(bdLocation);
}

public static BDLocation GCJ02_to_WGS84(BDLocation bdLocation) {
if (outOfChina(bdLocation)) {
return bdLocation;
}
BDLocation tmpLocation = new BDLocation();
tmpLocation.setLatitude(bdLocation.getLatitude());
tmpLocation.setLongitude(bdLocation.getLongitude());
BDLocation tmpLatLng = WGS84_to_GCJ02(tmpLocation);
double tmpLat = 2 * bdLocation.getLatitude() - tmpLatLng.getLatitude();
double tmpLng = 2 * bdLocation.getLongitude()
- tmpLatLng.getLongitude();
for (int i = 0; i < 0; ++i) {
tmpLocation.setLatitude(bdLocation.getLatitude());
tmpLocation.setLongitude(bdLocation.getLongitude());
tmpLatLng = WGS84_to_GCJ02(tmpLocation);
tmpLat = 2 * tmpLat - tmpLatLng.getLatitude();
tmpLng = 2 * tmpLng - tmpLatLng.getLongitude();
}
bdLocation.setLatitude(tmpLat);
bdLocation.setLongitude(tmpLng);
return bdLocation;
}

public static BDLocation WGS84_to_GCJ02(BDLocation bdLocation) {
if (outOfChina(bdLocation)) {
return bdLocation;
}
double dLat = transformLat(bdLocation.getLongitude() - 105.0,
bdLocation.getLatitude() - 35.0);
double dLon = transformLon(bdLocation.getLongitude() - 105.0,
bdLocation.getLatitude() - 35.0);
double radLat = bdLocation.getLatitude() / 180.0 * Math.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) * Math.PI);
dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * Math.PI);
bdLocation.setLatitude(bdLocation.getLatitude() + dLat);
bdLocation.setLongitude(bdLocation.getLongitude() + dLon);
return bdLocation;
}

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 * Math.PI) + 20.0 * Math.sin(2.0 * x
* Math.PI)) * 2.0 / 3.0;
ret += (20.0 * Math.sin(y * Math.PI) + 40.0 * Math.sin(y / 3.0
* Math.PI)) * 2.0 / 3.0;
ret += (160.0 * Math.sin(y / 12.0 * Math.PI) + 320 * Math.sin(y
* Math.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 * Math.PI) + 20.0 * Math.sin(2.0 * x
* Math.PI)) * 2.0 / 3.0;
ret += (20.0 * Math.sin(x * Math.PI) + 40.0 * Math.sin(x / 3.0
* Math.PI)) * 2.0 / 3.0;
ret += (150.0 * Math.sin(x / 12.0 * Math.PI) + 300.0 * Math.sin(x
/ 30.0 * Math.PI)) * 2.0 / 3.0;
return ret;
}

虽然理解起来很难，但是好用。

下面再讲把GPS坐标转换成百度坐标

// //GPS转百度
// 将GPS设备采集的原始GPS坐标转换成百度坐标
CoordinateConverter converter = new CoordinateConverter();
converter.from(CoordType.GPS);
// sourceLatLng待转换坐标
converter.coord(desLatLng1);
LatLng desLatLng = converter.convert();
double la = desLatLng.latitude;
double ln = desLatLng.longitude;
LatLng ll = new LatLng(la, ln);

这个是百度api里面有的方法