坐标系问题

地球坐标 (WGS84)

国际标准，GPS标准从 GPS 设备中取出的原始数据是就是这个
国际地图提供商一般使用的也是这个

火星坐标 (GCJ-02)

中国标准，行货 GPS 设备取出的最终数据是这个
国家龟腚： 国内出版的各种地图系统（包括电子形式），必须至少采用GCJ-02对地理位置进行首次加密。

百度坐标 (BD-09) -（这个是百度地图独有的编码方式，它对原有的经纬度进行了二次加密）

百度标准，百度 SDK，地图，Geocoding 用的都是这个。

我对百度地图转火星坐标以及火星坐标、地球坐标转百度地图坐标进行资料总结，也在网上找了资料，自己也实现了，下面我就列举出来

这是我在项目中做的操作

//火星坐标转百度坐标

CLLocationCoordinate2D test = CLLocationCoordinate2DMake([info.latitudeString floatValue], [info.longitudeString floatValue]);//将获取的经纬度转为CLLocationCoordinate2D类

////////////////坐标转换

NSDictionary* testdic = BMKConvertBaiduCoorFrom(test,BMK_COORDTYPE_COMMON);//调用百度提供的API BMKConvertBaiduCoorFrom()函数，转换坐标

CLLocationCoordinate2D lo = BMKCoorDictionaryDecode(testdic);//对转换后获得的经过base64加密之后的x，y坐标字典进行解密

CLLocation *cll = [[[CLLocation alloc]initWithLatitude:lo.latitude longitude:lo.longitude]locationMarsFromEarth];

locationMarsFromEarth方法是对CLLocation扩展的一个类由于不能上传文件，我把代码粘贴在下方

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

@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;

//从百度坐标到地图坐标

- (CLLocation*)locationEarthFromBaidu;

@end

#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+self.coordinate.latitude, lng+self.coordinate.longitude)

altitude:self.altitude

horizontalAccuracy:self.horizontalAccuracy

verticalAccuracy:self.verticalAccuracy

course:self.course

speed:self.speed

timestamp:self.timestamp];

}

- (CLLocation*)locationEarthFromMars

{

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(self.coordinate.latitude-lat, self.coordinate.longitude-lng)

altitude:self.altitude

horizontalAccuracy:self.horizontalAccuracy

verticalAccuracy:self.verticalAccuracy

course:self.course

speed:self.speed

timestamp:self.timestamp];

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];

}

-(CLLocation*)locationEarthFromBaidu

{

double lat = 0.0;

double lng = 0.0;

CLLocation *Mars = [self locationMarsFromBaidu];

transform_earth_from_mars(Mars.coordinate.latitude, Mars.coordinate.longitude, &lat, &lng);

return [[CLLocation alloc] initWithCoordinate:CLLocationCoordinate2DMake(Mars.coordinate.latitude-lat, Mars.coordinate.longitude-lng)

altitude:self.altitude

horizontalAccuracy:self.horizontalAccuracy

verticalAccuracy:self.verticalAccuracy

course:self.course

speed:self.speed

timestamp:self.timestamp];

return nil;

}

@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) + 320 * 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 = dLat;

*tarLng = dLon;

}

// --- transform_earth_from_mars end ---

// --- transform_mars_vs_bear_paw ---

const double x_pi = M_PI * 3000.0 / 180.0;

void transform_mars_from_baidu(double gg_lat, double gg_lon, double *bd_lat, double *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, double *gg_lat, double *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);

}

来源于http://blog.sina.com.cn/s/blog_91616f7a0102w4a7.html