iOS苹果地图开发如何将“地球坐标”如何转“火星坐标”?

『导言』

iOS 开发使用苹果原生地图时候,需要将地球坐标转化为火星坐标。为啥呢?如何转换?分析如下:

既然是在国内,存储⼀律⽤⽕星坐标,利用MapKit框架开发可以精确(苹果原生的用CLLocation定位的是真实经纬度坐标,即地球坐标;但在“国内苹果原生地图的数据是由高德地图提供”,所以需要将地球坐标转成火星坐标;可以用第三方库CLLocation+Sino来实现转换;否则使用会有偏差。CLLocation+Sino的Demo下载

温馨提示:

  • 如果用高德百度等第三方SDK进行开发,他们内部做了转换,所以不需要转换
  • 如果使用苹果原生地图需要地球坐标火星坐标

重点代码:

地球地址转化为火星地址
location = [location locationMarsFromEarth];

-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
    NSLog(@"定位成功");
    
    //获取当前位置----是地球地址(国际地址)
    //manager.location
    CLLocation *location = manager.location;
    
    //地球地址转化为火星地址
    location = [location locationMarsFromEarth];
    
    //地图的中心点设置为当前位置
    //  苹果地图使用的是火星地址
    _mapView.centerCoordinate = location.coordinate;

    [_locationManager stopUpdatingLocation];
}

CLLocation+Sino.h

//
//  CLLocation+Sino.h
//
//  Created by i0xbean@gmail.com on 13-4-26.
//  火星坐标系转换扩展
//
//  earth(国外 WGS84), mars(国内 GCJ-02), bearPaw(百度 BD-09) 坐标系间相互转换
//  未包含 mars2earth. 需要这个可参考 http://xcodev.com/131.html

#import <CoreLocation/CoreLocation.h>

@interface CLLocation (Sino)

- (CLLocation*)locationMarsFromEarth;
//- (CLLocation*)locationEarthFromMars; // 未实现

- (CLLocation*)locationBearPawFromMars;
- (CLLocation*)locationMarsFromBearPaw;

@end

CLLocation+Sino.m

//
//  CLLocation+Sino.h
//
//  Created by i0xbean@gmail.com on 13-4-26.
//  火星坐标系转换扩展

#import "CLLocation+Sino.h"

void transform_earth_2_mars(double lat, double lng, double* tarLat, double* tarLng);
void transform_mars_2_bear_paw(double lat, double lng, double* tarLat, double* tarLng);
void transform_bear_paw_2_mars(double lat, double lng, double* tarLat, double* tarLng);

@implementation CLLocation (Sino)

- (CLLocation*)locationMarsFromEarth;
{
    double lat = 0.0;
    double lng = 0.0;
    transform_earth_2_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*)locationBearPawFromMars;
{
    double lat = 0.0;
    double lng = 0.0;
    transform_mars_2_bear_paw(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*)locationMarsFromBearPaw;
{
    double lat = 0.0;
    double lng = 0.0;
    transform_bear_paw_2_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_2_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_2_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_2_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_2_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_2_mars_lat(lng - 105.0, lat - 35.0);
    double dLon = transform_earth_2_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_2_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_2_bear_paw(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_bear_paw_2_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);
}

// --- transform_mars_vs_bear_paw end ---
温馨提示:如下'链接'为我写的升级版地图相关。

iOS 火星坐标/地球坐标/百度坐标整理及解决方案汇总?如何转火星坐标?

参考链接:

[1].ios 百度地图,火星坐标,地球坐标互转

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