iOS 百度坐标、GPS坐标、 高德坐标相互转换

来源：https://www.jianshu.com/p/27dbe24e8771

/**
 百度坐标转高德坐标

 @param glat 纬度
 @param glon 经度
 @return 数组【转换后的纬度，转换后的经度】
 */
+ (NSArray *)bd09llToGCJLat:(double)glat lon:(double)glon {
    double X_PI = M_PI * 3000.0 / 180.0;
    double x = glon - 0.0065;
    double y = glat - 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);
    double lat = z * sin(theta);
    double lon = z * cos(theta);
    NSArray *latlon = @[[NSNumber numberWithDouble:lat],[NSNumber numberWithDouble:lon]];
    
    return latlon;
}


/**
 高德坐标转系统自带坐标

 @param array 数组 需要转换的坐标【纬度，经度】
 @return 数组【转换后的纬度，转换后的经度】
 */
+ (NSArray *)gcjToWGS:(NSArray *)array {
    double lat = [array.firstObject doubleValue];
    double lon = [array.lastObject doubleValue];
    if ([self outOfChinalat:lat lon:lon]){
        return @[[NSNumber numberWithDouble:lat],[NSNumber numberWithDouble:lon]];
    }
    NSArray *latlon = [self deltalat:lat lon:lon];
    return latlon;
}

+ (BOOL)outOfChinalat:(double)lat lon:(double)lon {
    if (lon < 72.004 || lon > 137.8347)
        return true;
    if (lat < 0.8293 || lat > 55.8271)
        return true;
    return false;
}

+ (NSArray *)deltalat:(double)wgLat lon:(double)wgLon {
    double OFFSET = 0.00669342162296594323;
    double AXIS = 6378245.0;
    
    double dLat = [self transformLatx:(wgLon - 105.0) lon:(wgLat - 35.0)];
    double dLon = [self transformLonx:(wgLon - 105.0) lon:(wgLat - 35.0)];
    double radLat = wgLat / 180.0 * M_PI;
    double magic = sin(radLat);
    magic = 1 - OFFSET * magic * magic;
    double sqrtMagic = sqrt(magic);
    dLat = (dLat * 180.0) / ((AXIS * (1 - OFFSET)) / (magic * sqrtMagic) * M_PI);
    dLon = (dLon * 180.0) / (AXIS / sqrtMagic * cos(radLat) * M_PI);
    return @[[NSNumber numberWithDouble:(wgLat - dLat)],[NSNumber numberWithDouble:(wgLon - dLon)]];
}

+ (double)transformLatx:(double)x lon:(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)transformLonx:(double)x lon:(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;
}