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。
//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
