iOS在地图上WGS84、GCJ-02、BD-09互转解决方案

          该项目的最新进展包括地图共享模块，android同事集团开始，使用百度地图sdk，我开始回，运用iOS SDK的mapkit做，之后，问题是，用纬度和经度坐标iOS端和Android端出现了比較大偏差。查了下资料苹果地图在大陆的数据源是高德的，查了下高德採用GCJ-02, 百度map sdk 採用的是BD-09。仅仅好写了个类在发送和接收时做好转换，稍微蛋疼。Github上有人写了一个现成的转换类，能够參考參考传送门 。其主要代码见下：

头文件：

#import <Foundation/Foundation.h>
#import <CoreLocation/CoreLocation.h>
@interface JZLocationConverter : NSObject

/**
 *	@brief	世界标准地理坐标(WGS-84) 转换成 中国国測局地理坐标（GCJ-02）<火星坐标>
 *
 *  ####仅仅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	中国国測局地理坐标（GCJ-02）<火星坐标>
 */
+ (CLLocationCoordinate2D)wgs84ToGcj02:(CLLocationCoordinate2D)location;


/**
 *	@brief	中国国測局地理坐标（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，须要精确定位情景慎用
 *
 *	@param 	location 	中国国測局地理坐标（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	中国国測局地理坐标（GCJ-02）<火星坐标> 转换成 百度地理坐标（BD-09)
 *
 *	@param 	location 	中国国測局地理坐标（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 中国国測局地理坐标（GCJ-02）<火星坐标>
 *
 *	@param 	location 	百度地理坐标（BD-09)
 *
 *	@return	中国国測局地理坐标（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，须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

实现文件

#import "JZLocationConverter.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 JZLocationConverter

+ (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

測试用例：

    CLLocationCoordinate2D gcj02 = CLLocationCoordinate2DMake(114.21892734521,29.575429778924);
    CLLocationCoordinate2D bd09 = [JZLocationConverter gcj02ToBd09:gcj02];
    NSLog(@"%f,%f", bd09.latitude, bd09.longitude); 

    // http://developer.baidu.com/map/index.php?title=webapi/guide/changeposition
    // JZLocationConverter 測试数据: 114.21892734521,29.575429778924  ; 转化结果: 114.224960,29.581853
    // 百度api  測试数据: 114.21892734521,29.575429778924  ; 百度api转换结果: 114.22539195429,29.581585367458

         整体来说，存在一点偏差，但跟处理前的效果比一下。相对能够接受了些。

參考：

http://blog.csdn.net/jiajiayouba/article/details/25140967

http://developer.baidu.com/map/index.php?

title=webapi/guide/changeposition

http://blog.csdn.net/winnyrain/article/details/22233559

http://www.kuaifenxiang.net/article/17

http://blog.csdn.net/coolypf/article/details/8569813

http://www.cppblog.com/socketref/archive/2011/06/29/149713.html

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