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) {
4000
this.wgLat = wgLat;
}

public double getWgLon() {
return wgLon;
}

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

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