LocationManager定位国内偏移，WGS-84、GCJ-02、BD-09之间转换

开发过程中我们会不可避免的用到定位功能，而不同的方法得到的坐标也会有些偏差，比如系统的CLLocationManager定位得到的是世界标准地理坐标(WGS-84)、高德SDK定位得到的是火星坐标（GCJ-02）、百度SDK定位得到的是百度地理坐标（BD-09），那这些坐标之间是怎么实现转换的呢

<span style="font-family: Arial, Helvetica, sans-serif;">//  CoordinateTransformation.h</span>

//  Created by MLS on 15/12/22.
//  Copyright © 2015年 MLS. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>

@interface CoordinateTransformation : NSObject

/**
*	@brief	判断是否在中国
*
*	@param 	location 	世界标准地理坐标(WGS-84)
*
*	@return	中国国测局地理坐标（GCJ-02）<火星坐标>
*/
+(BOOL)isLocationOutOfChina:(CLLocationCoordinate2D)location;

/**
*	@brief	世界标准地理坐标(WGS-84) 转换成 中国国测局地理坐标（GCJ-02）<火星坐标>
*
*  ####只在中国大陆的范围的坐标有效，以外直接返回世界标准坐标
*
*	@param 	location 	世界标准地理坐标(WGS-84)
*
*	@return	中国国测局地理坐标（GCJ-02）<火星坐标>
*/
+ (CLLocationCoordinate2D)WGS84ToGCJ02:(CLLocationCoordinate2D)location;

/**
*	@brief	中国国测局地理坐标（GCJ-02） 转换成 世界标准地理坐标（WGS-84）
*
*  ####此接口有1－2米左右的误差，需要精确定位情景慎用
*
*	@param 	location 	中国国测局地理坐标（GCJ-02）
*
*	@return	世界标准地理坐标（WGS-84）
*/
+ (CLLocationCoordinate2D)GCJ02ToWGS84:(CLLocationCoordinate2D)location;

/**
*	@brief	世界标准地理坐标(WGS-84) 转换成 百度地理坐标（BD-09)
*
*	@param 	location 	世界标准地理坐标(WGS-84)
*
*	@return	百度地理坐标（BD-09)
*/
+ (CLLocationCoordinate2D)WGS84ToBD09:(CLLocationCoordinate2D)location;

/**
*	@brief	中国国测局地理坐标（GCJ-02）<火星坐标> 转换成 百度地理坐标（BD-09)
*
*	@param 	location 	中国国测局地理坐标（GCJ-02）<火星坐标>
*
*	@return	百度地理坐标（BD-09)
*/
+ (CLLocationCoordinate2D)GCJ02ToBD09:(CLLocationCoordinate2D)location;

/**
*	@brief	百度地理坐标（BD-09) 转换成 中国国测局地理坐标（GCJ-02）<火星坐标>
*
*	@param 	location 	百度地理坐标（BD-09)
*
*	@return	中国国测局地理坐标（GCJ-02）<火星坐标>
*/
+ (CLLocationCoordinate2D)BD09ToGCJ02:(CLLocationCoordinate2D)location;

/**
*	@brief	百度地理坐标（BD-09) 转换成 世界标准地理坐标（WGS-84）
*
*  ####此接口有1－2米左右的误差，需要精确定位情景慎用
*
*	@param 	location 	百度地理坐标（BD-09)
*
*	@return	世界标准地理坐标（WGS-84）
*/
+ (CLLocationCoordinate2D)BD09ToWGS84:(CLLocationCoordinate2D)location;

@end

//  CoordinateTransformation.m

//  Created by MLS on 15/12/22.
//  Copyright © 2015年 MLS. All rights reserved.
//

#import "CoordinateTransformation.h"
//#import <CoreLocation/CoreLocation.h>

#define LAT_OFFSET_0(x,y) -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * sqrt(fabs(x))
#define LAT_OFFSET_1 (20.0 * sin(6.0 * x * M_PI) + 20.0 * sin(2.0 * x * M_PI)) * 2.0 / 3.0
#define LAT_OFFSET_2 (20.0 * sin(y * M_PI) + 40.0 * sin(y / 3.0 * M_PI)) * 2.0 / 3.0
#define LAT_OFFSET_3 (160.0 * sin(y / 12.0 * M_PI) + 320 * sin(y * M_PI / 30.0)) * 2.0 / 3.0

#define LON_OFFSET_0(x,y) 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * sqrt(fabs(x))
#define LON_OFFSET_1 (20.0 * sin(6.0 * x * M_PI) + 20.0 * sin(2.0 * x * M_PI)) * 2.0 / 3.0
#define LON_OFFSET_2 (20.0 * sin(x * M_PI) + 40.0 * sin(x / 3.0 * M_PI)) * 2.0 / 3.0
#define LON_OFFSET_3 (150.0 * sin(x / 12.0 * M_PI) + 300.0 * sin(x / 30.0 * M_PI)) * 2.0 / 3.0

#define RANGE_LON_MAX 137.8347
#define RANGE_LON_MIN 72.004
#define RANGE_LAT_MAX 55.8271
#define RANGE_LAT_MIN 0.8293
// jzA = 6378245.0, 1/f = 298.3
// b = a * (1 - f)
// ee = (a^2 - b^2) / a^2;
#define jzA 6378245.0
#define jzEE 0.00669342162296594323

@implementation <span style="font-family: Arial, Helvetica, sans-serif;">CoordinateTransformation</span>

//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)transformLat:(double)x BDLon:(double)y
{
double ret = LAT_OFFSET_0(x, y);
ret += LAT_OFFSET_1;
ret += LAT_OFFSET_2;
ret += LAT_OFFSET_3;
return ret;
}

+ (double)transformLon:(double)x BDLon:(double)y
{
double ret = LON_OFFSET_0(x, y);
ret += LON_OFFSET_1;
ret += LON_OFFSET_2;
ret += LON_OFFSET_3;
return ret;
}

+ (BOOL)outOfChina:(double)lat BDLon:(double)lon
{
if (lon < RANGE_LON_MIN || lon > RANGE_LON_MAX)
return true;
if (lat < RANGE_LAT_MIN || lat > RANGE_LAT_MAX)
return true;
return false;
}

+ (CLLocationCoordinate2D)GCJ02Encrypt:(double)ggLat BDLon:(double)ggLon
{
CLLocationCoordinate2D resPoint;
double mgLat;
double mgLon;
if ([self outOfChina:ggLat BDLon:ggLon]) {
resPoint.latitude = ggLat;
resPoint.longitude = ggLon;
return resPoint;
}
double dLat = [self transformLat:(ggLon - 105.0)BDLon:(ggLat - 35.0)];
double dLon = [self transformLon:(ggLon - 105.0) BDLon:(ggLat - 35.0)];
double radLat = ggLat / 180.0 * M_PI;
double magic = sin(radLat);
magic = 1 - jzEE * magic * magic;
double sqrtMagic = sqrt(magic);
dLat = (dLat * 180.0) / ((jzA * (1 - jzEE)) / (magic * sqrtMagic) * M_PI);
dLon = (dLon * 180.0) / (jzA / sqrtMagic * cos(radLat) * M_PI);
mgLat = ggLat + dLat;
mgLon = ggLon + dLon;

resPoint.latitude = mgLat;
resPoint.longitude = mgLon;
return resPoint;
}

+ (CLLocationCoordinate2D)GCJ02Decrypt:(double)gjLat gjLon:(double)gjLon {
CLLocationCoordinate2D  gPt = [self GCJ02Encrypt:gjLat BDLon:gjLon];
double dLon = gPt.longitude - gjLon;
double dLat = gPt.latitude - gjLat;
CLLocationCoordinate2D pt;
pt.latitude = gjLat - dLat;
pt.longitude = gjLon - dLon;
return pt;
}

+ (CLLocationCoordinate2D)BD09Decrypt:(double)BDLat BDLon:(double)BDLon
{
CLLocationCoordinate2D GCJPt;
double x = BDLon - 0.0065, y = BDLat - 0.006;
double z = sqrt(x * x + y * y) - 0.00002 * sin(y * M_PI);
double theta = atan2(y, x) - 0.000003 * cos(x * M_PI);
GCJPt.longitude = z * cos(theta);
GCJPt.latitude = z * sin(theta);
return GCJPt;
}

+(CLLocationCoordinate2D)BD09Encrypt:(double)ggLat BDLon:(double)ggLon
{
CLLocationCoordinate2D BDPt;
double x = ggLon, y = ggLat;
double z = sqrt(x * x + y * y) + 0.00002 * sin(y * M_PI);
double theta = atan2(y, x) + 0.000003 * cos(x * M_PI);
BDPt.longitude = z * cos(theta) + 0.0065;
BDPt.latitude = z * sin(theta) + 0.006;
return BDPt;
}

+ (CLLocationCoordinate2D)WGS84ToGCJ02:(CLLocationCoordinate2D)location
{
return [self GCJ02Encrypt:location.latitude BDLon:location.longitude];
}

+ (CLLocationCoordinate2D)GCJ02ToWGS84:(CLLocationCoordinate2D)location
{
return [self GCJ02Decrypt:location.latitude gjLon:location.longitude];
}

+ (CLLocationCoordinate2D)WGS84ToBD09:(CLLocationCoordinate2D)location
{
CLLocationCoordinate2D GCJ02Pt = [self GCJ02Encrypt:location.latitude
BDLon:location.longitude];
return [self BD09Encrypt:GCJ02Pt.latitude BDLon:GCJ02Pt.longitude] ;
}

+ (CLLocationCoordinate2D)GCJ02ToBD09:(CLLocationCoordinate2D)location
{
return  [self BD09Encrypt:location.latitude BDLon:location.longitude];
}

+ (CLLocationCoordinate2D)BD09ToGCJ02:(CLLocationCoordinate2D)location
{
return [self BD09Decrypt:location.latitude BDLon:location.longitude];
}

+ (CLLocationCoordinate2D)BD09ToWGS84:(CLLocationCoordinate2D)location
{
CLLocationCoordinate2D GCJ02 = [self BD09ToGCJ02:location];
return [self GCJ02Decrypt:GCJ02.latitude gjLon:GCJ02.longitude];
}

@end