iOS地球坐标，火星坐标，百度坐标互转

//  CLLocation+YCLocation.h
//  YCMapViewDemo
//
//  Created by gongliang on 13-9-16.
//  Copyright (c) 2013年 gongliang. All rights reserved.
//  火星坐标系转换扩展
/*
从 CLLocationManager 取出来的经纬度放到 mapView 上显示，是错误的!
从 CLLocationManager 取出来的经纬度去 Google Maps API 做逆地址解析，当然是错的！
从 MKMapView 取出来的经纬度去 Google Maps API 做逆地址解析终于对了。去百度地图API做逆地址解析，依旧是错的！
从上面两处取的经纬度放到百度地图上显示都是错的！错的！的！

分为 地球坐标，火星坐标（iOS mapView 高德 ， 国内google ,搜搜、阿里云 都是火星坐标），百度坐标(百度地图数据主要都是四维图新提供的)

火星坐标: MKMapView
地球坐标: CLLocationManager

当用到CLLocationManager 得到的数据转化为火星坐标, MKMapView不用处理

API                坐标系
百度地图API         百度坐标
腾讯搜搜地图API      火星坐标
搜狐搜狗地图API      搜狗坐标
阿里云地图API       火星坐标
图吧MapBar地图API   图吧坐标
高德MapABC地图API   火星坐标
灵图51ditu地图API   火星坐标

*/

#import <CoreLocation/CoreLocation.h>

@interface CLLocation (YCLocation)

//从地图坐标转化到火星坐标
- (CLLocation*)locationMarsFromEarth;

//从火星坐标转化到百度坐标
- (CLLocation*)locationBaiduFromMars;

//从百度坐标到火星坐标
- (CLLocation*)locationMarsFromBaidu;

//从火星坐标到地图坐标
//- (CLLocation*)locationEarthFromMars; // 未实现

@end

//
//  CLLocation+YCLocation.m
//  YCMapViewDemo
//
//  Created by gongliang on 13-9-16.
//  Copyright (c) 2013年 gongliang. All rights reserved.
//

#import "CLLocation+YCLocation.h"

void transform_earth_from_mars(double lat, double lng, double* tarLat, double* tarLng);
void transform_mars_from_baidu(double lat, double lng, double* tarLat, double* tarLng);
void transform_baidu_from_mars(double lat, double lng, double* tarLat, double* tarLng);

@implementation CLLocation (YCLocation)

- (CLLocation*)locationMarsFromEarth
{
double lat = 0.0;
double lng = 0.0;
transform_earth_from_mars(self.coordinate.latitude, self.coordinate.longitude, &lat, &lng);
return [[CLLocation alloc] initWithCoordinate:CLLocationCoordinate2DMake(lat, lng)
altitude:self.altitude
horizontalAccuracy:self.horizontalAccuracy
verticalAccuracy:self.verticalAccuracy
course:self.course
speed:self.speed
timestamp:self.timestamp];
}

- (CLLocation*)locationEarthFromMars
{
// 二分法查纠偏文件
// http://xcodev.com/131.html return nil;
}

- (CLLocation*)locationBaiduFromMars
{
double lat = 0.0;
double lng = 0.0;
transform_mars_from_baidu(self.coordinate.latitude, self.coordinate.longitude, &lat, &lng);
return [[CLLocation alloc] initWithCoordinate:CLLocationCoordinate2DMake(lat, lng)
altitude:self.altitude
horizontalAccuracy:self.horizontalAccuracy
verticalAccuracy:self.verticalAccuracy
course:self.course
speed:self.speed
timestamp:self.timestamp];
}

- (CLLocation*)locationMarsFromBaidu
{
double lat = 0.0;
double lng = 0.0;
transform_baidu_from_mars(self.coordinate.latitude, self.coordinate.longitude, &lat, &lng);
return [[CLLocation alloc] initWithCoordinate:CLLocationCoordinate2DMake(lat, lng)
altitude:self.altitude
horizontalAccuracy:self.horizontalAccuracy
verticalAccuracy:self.verticalAccuracy
course:self.course
speed:self.speed
timestamp:self.timestamp];
}

@end

// --- transform_earth_from_mars ---
// 参考来源：https://on4wp7.codeplex.com/SourceControl/changeset/view/21483#353936
// Krasovsky 1940
//
// a = 6378245.0, 1/f = 298.3
// b = a * (1 - f)
// ee = (a^2 - b^2) / a^2;
const double a = 6378245.0;
const double ee = 0.00669342162296594323;

bool transform_sino_out_china(double lat, double lon)
{
if (lon < 72.004 || lon > 137.8347)
return true;
if (lat < 0.8293 || lat > 55.8271)
return true;
return false;
}

double transform_earth_from_mars_lat(double x, double y)
{
double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * sqrt(abs(x));
ret += (20.0 * sin(6.0 * x * M_PI) + 20.0 * sin(2.0 * x * M_PI)) * 2.0 / 3.0;
ret += (20.0 * sin(y * M_PI) + 40.0 * sin(y / 3.0 * M_PI)) * 2.0 / 3.0;
ret += (160.0 * sin(y / 12.0 * M_PI) + 3320 * sin(y * M_PI / 30.0)) * 2.0 / 3.0;
return ret;
}

double transform_earth_from_mars_lng(double x, double y)
{
double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * sqrt(abs(x));
ret += (20.0 * sin(6.0 * x * M_PI) + 20.0 * sin(2.0 * x * M_PI)) * 2.0 / 3.0;
ret += (20.0 * sin(x * M_PI) + 40.0 * sin(x / 3.0 * M_PI)) * 2.0 / 3.0;
ret += (150.0 * sin(x / 12.0 * M_PI) + 300.0 * sin(x / 30.0 * M_PI)) * 2.0 / 3.0;
return ret;
}

void transform_earth_from_mars(double lat, double lng, double* tarLat, double* tarLng)
{
if (transform_sino_out_china(lat, lng))
{
*tarLat = lat;
*tarLng = lng;
return;
}
double dLat = transform_earth_from_mars_lat(lng - 105.0, lat - 35.0);
double dLon = transform_earth_from_mars_lng(lng - 105.0, lat - 35.0);
double radLat = lat / 180.0 * M_PI;
double magic = sin(radLat);
magic = 1 - ee * magic * magic;
double sqrtMagic = sqrt(magic);
dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * M_PI);
dLon = (dLon * 180.0) / (a / sqrtMagic * cos(radLat) * M_PI);
*tarLat = lat + dLat;
*tarLng = lng + dLon;
}

// --- transform_earth_from_mars end ---
// --- transform_mars_vs_bear_paw ---
// 参考来源：http://blog.woodbunny.com/post-68.html
const double x_pi = M_PI * 3000.0 / 180.0;

void transform_mars_from_baidu(double gg_lat, double gg_lon, doubledouble *bd_lat, doubledouble *bd_lon)
{
double x = gg_lon, y = gg_lat;
double z = sqrt(x * x + y * y) + 0.00002 * sin(y * x_pi);
double theta = atan2(y, x) + 0.000003 * cos(x * x_pi);
*bd_lon = z * cos(theta) + 0.0065;
*bd_lat = z * sin(theta) + 0.006;
}

void transform_baidu_from_mars(double bd_lat, double bd_lon, doubledouble *gg_lat, doubledouble *gg_lon)
{
double x = bd_lon - 0.0065, y = bd_lat - 0.006;
double z = sqrt(x * x + y * y) - 0.00002 * sin(y * x_pi);
double theta = atan2(y, x) - 0.000003 * cos(x * x_pi);
*gg_lon = z * cos(theta);
*gg_lat = z * sin(theta);
}