ios 定位坐标转换国际坐标到火星坐标

关于这篇文章，ios MapKit 运动轨迹定位只能前台绘制，无论怎么配置；

因为ios不允许处了核心框架以外的第三方框架使用后台定位了

-(void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation

这句在后代无法回调

但是核心框架的可以：

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations 

但是这句回调之后获取的位置是国际定位，不是中国的定位，中国定位使用的是火星坐标，所以后台定位的话，需要桌标转换，这里参考了一篇文章：

https://blog.csdn.net/swingpyzf/article/details/16972351

整理代码如下：

WGS84TOGCJ02.h

#ifndef WGS84TOGCJ02_h
#define WGS84TOGCJ02_h
#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>

@interface WGS84TOGCJ02 : NSObject
//判断是否已经超出中国范围
+(BOOL)isLocationOutOfChina:(CLLocationCoordinate2D)location;
//转GCJ-02
+(CLLocationCoordinate2D)transformFromWGSToGCJ:(CLLocationCoordinate2D)wgsLoc;
@end

#endif /* WGS84TOGCJ02_h */

WGS84TOGCJ02.m

#import "WGS84TOGCJ02.h"

const double a = 6378245.0;
const double ee = 0.00669342162296594323;
const double pi = 3.14159265358979324;

@implementation WGS84TOGCJ02

+(CLLocationCoordinate2D)transformFromWGSToGCJ:(CLLocationCoordinate2D)wgsLoc
{
    CLLocationCoordinate2D adjustLoc;
    if([self isLocationOutOfChina:wgsLoc]){
        adjustLoc = wgsLoc;
    }else{
        double adjustLat = [self transformLatWithX:wgsLoc.longitude - 105.0 withY:wgsLoc.latitude - 35.0];
        double adjustLon = [self transformLonWithX:wgsLoc.longitude - 105.0 withY:wgsLoc.latitude - 35.0];
        double radLat = wgsLoc.latitude / 180.0 * pi;
        double magic = sin(radLat);
        magic = 1 - ee * magic * magic;
        double sqrtMagic = sqrt(magic);
        adjustLat = (adjustLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        adjustLon = (adjustLon * 180.0) / (a / sqrtMagic * cos(radLat) * pi);
        adjustLoc.latitude = wgsLoc.latitude + adjustLat;
        adjustLoc.longitude = wgsLoc.longitude + adjustLon;
    }
    return adjustLoc;
}

//判断是不是在中国
+(BOOL)isLocationOutOfChina:(CLLocationCoordinate2D)location
{
    if (location.longitude < 72.004 || location.longitude > 137.8347 || location.latitude < 0.8293 || location.latitude > 55.8271)
        return YES;
    return NO;
}

+(double)transformLatWithX:(double)x withY:(double)y
{
    double lat = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * sqrt(abs(x));
    lat += (20.0 * sin(6.0 * x * pi) + 20.0 *sin(2.0 * x * pi)) * 2.0 / 3.0;
    lat += (20.0 * sin(y * pi) + 40.0 * sin(y / 3.0 * pi)) * 2.0 / 3.0;
    lat += (160.0 * sin(y / 12.0 * pi) + 320 * sin(y * pi / 30.0)) * 2.0 / 3.0;
    return lat;
}

+(double)transformLonWithX:(double)x withY:(double)y
{
    double lon = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * sqrt(abs(x));
    lon += (20.0 * sin(6.0 * x * pi) + 20.0 * sin(2.0 * x * pi)) * 2.0 / 3.0;
    lon += (20.0 * sin(x * pi) + 40.0 * sin(x / 3.0 * pi)) * 2.0 / 3.0;
    lon += (150.0 * sin(x / 12.0 * pi) + 300.0 * sin(x / 30.0 * pi)) * 2.0 / 3.0;
    return lon;
}

@end

然后修改一下后台可以回调的地方：

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
    // 设备的当前位置
    CLLocation *currLocation = [locations lastObject];
    CLLocationCoordinate2D endCoordinate;
    //判断是不是属于国内范围
    if (![WGS84TOGCJ02 isLocationOutOfChina:[currLocation coordinate]]) {
        //转换后的coord
        endCoordinate = [WGS84TOGCJ02 transformFromWGSToGCJ:[currLocation coordinate]];
    }
    
    NSString *latitude = [NSString stringWithFormat:@"纬度:%3.5f",currLocation.coordinate.latitude];
    NSString *longitude = [NSString stringWithFormat:@"经度:%3.5f",currLocation.coordinate.longitude];
    NSString *altitude = [NSString stringWithFormat:@"高度值:%3.5f",currLocation.altitude];
    
    NSLog(@"位置发生改变:纬度:%@,经度:%@,高度:%@",latitude,longitude,altitude);
    
    if (_locationMutableArray.count != 0) {
        
        //从位置数组中取出最新的位置数据
        NSString *locationStr = _locationMutableArray.lastObject;
        NSArray *temp = [locationStr componentsSeparatedByString:@","];
        NSString *latitudeStr = temp[0];
        NSString *longitudeStr = temp[1];
        CLLocationCoordinate2D startCoordinate = CLLocationCoordinate2DMake([latitudeStr doubleValue], [longitudeStr doubleValue]);
        
        //移动距离的计算
        double meters = [self calculateDistanceWithStart:startCoordinate end:endCoordinate];
        NSLog(@"移动的距离为%f米",meters);
        
        //为了美化移动的轨迹,移动的位置超过10米,方可添加进位置的数组
        if (meters >= 10) {
            
            NSLog(@"添加进位置数组");
            NSString *locationString = [NSString stringWithFormat:@"%f,%f",endCoordinate.latitude, endCoordinate.longitude];
            [_locationMutableArray addObject:locationString];
            
            //开始绘制轨迹
            CLLocationCoordinate2D pointsToUse[2];
            pointsToUse[0] = startCoordinate;
            pointsToUse[1] = endCoordinate;
            //调用 addOverlay 方法后,会进入 rendererForOverlay 方法,完成轨迹的绘制
            MKPolyline *lineOne = [MKPolyline polylineWithCoordinates:pointsToUse count:2];
            [_mapView addOverlay:lineOne];
        } else {
            NSLog(@"不添加进位置数组");
        }
    } else {
        //存放位置的数组,如果数组包含的对象个数为0,那么说明是第一次进入,将当前的位置添加到位置数组
        NSString *locationString = [NSString stringWithFormat:@"%f,%f",endCoordinate.latitude, endCoordinate.longitude];
        [_locationMutableArray addObject:locationString];
    }
    
}

关于一些ios11的后台定位配置：

Privacy - Location Always and When In Use Usage Description

Privacy - Location When In Use Usage Description