# 经纬度偏移转换

3.百度坐标系:bd-09，百度坐标系是在GCJ－02坐标系的基础上再次加密偏移后形成的坐标系，只适用于百度地图。(目前百度API提供了从其它坐标系转换为百度坐标系的API，但却没有从百度坐标系转为其他坐标系的API)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace Extensions
{
public class GpsExtension
{
public static double pi = 3.1415926535897932384626;
public static double x_pi = 3.14159265358979324 * 3000.0 / 180.0;
public static double a = 6378245.0;
public static double ee = 0.00669342162296594323;

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

/// <summary>
/// 火星坐标系 (GCJ-02) to 84 * * @param lon * @param lat * @return
/// </summary>
/// <param name="lat"></param>
/// <param name="lon"></param>
/// <returns></returns>
public static double[] gcj02_To_Gps84(double lat, double lon)
{
double[] gps = transform(lat, lon);
double lontitude = lon * 2 - gps[1];
double latitude = lat * 2 - gps[0];
return new double[] { 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 lat
* @param lon
*/
public static double[] gcj02_To_Bd09(double lat, double lon)
{
double x = lon, y = lat;
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);
double tempLon = z * Math.Cos(theta) + 0.0065;
double tempLat = z * Math.Sin(theta) + 0.006;
double[] gps = { tempLat, tempLon };
return gps;
}

/**
* * 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 double[] bd09_To_Gcj02(double lat, double lon)
{
double x = lon - 0.0065, y = lat - 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);
double tempLon = z * Math.Cos(theta);
double tempLat = z * Math.Sin(theta);
double[] gps = { tempLat, tempLon };
return gps;
}

/**将gps84转为bd09
* @param lat
* @param lon
* @return
*/
public static double[] gps84_To_bd09(double lat, double lon)
{
double[] gcj02 = gps84_To_Gcj02(lat, lon);
double[] bd09 = gcj02_To_Bd09(gcj02[0], gcj02[1]);
return bd09;
}
public static double[] bd09_To_gps84(double lat, double lon)
{
double[] gcj02 = bd09_To_Gcj02(lat, lon);
double[] gps84 = gcj02_To_Gps84(gcj02[0], gcj02[1]);
//保留小数点后六位
gps84[0] = retain6(gps84[0]);
gps84[1] = retain6(gps84[1]);
return gps84;
}

/**保留小数点后六位
* @param num
* @return
*/
private static double retain6(double num)
{
String result = String.Format("%.6f", num);
return Convert.ToDouble(result);
}
}
}

posted @ 2018-11-02 09:43  _York  阅读(2499)  评论(0编辑  收藏