在iphone xcode中存储纬度经度的最佳和最精确的数据类型是什么?

I am building a geolocation based app and i want to know which data type is best for storing lat/long i am using doubleValue but i think we can be more precise like 10 decimal places .

我正在构建一个基于地理定位的应用程序，我想知道哪种数据类型最适合存储lat/long，我使用的是doubleValue，但我认为我们可以更精确，比如10位小数。

4 个解决方案

#1

double is the value used by the iOS itself. iOS uses CLLocationDegrees to represent lat/long values which is a typedef of double.

double是iOS本身使用的值。iOS使用CLLocationDegrees来表示lat/long值，这是double类型的类型定义。

IMO, using double/CLLocationDegrees would be the best choice.

IMO，使用双/CLLocationDegrees是最好的选择。

#2

Looking at the definition of CLLocationCoordinate2D:

看CLLocationCoordinate2D的定义:

typedef struct {
    CLLocationDegrees latitude;
    CLLocationDegrees longitude;
} 
CLLocationCoordinate2D;

and then the location of CLLocationDegrees;

然后是CLLocationDegrees的位置;

typedef double CLLocationDegrees;

we can see that the precision is given as double. Thus, you can't make it better than that.

我们可以看出精度是双倍的。因此，你不能让它变得更好。

#3

There's already an answer to that in the iOS SDK :)

iOS SDK中已经有了答案

Take a look at CLLocationCoordinate2D - it's used by CoreLocation to store it's lat/lngs using the CLLocationDegrees type. If that's the accuracy CoreLocation gives you then that's a accuarate as it's going to get!

看一下CLLocationCoordinate2D -它是由CoreLocation用来存储它的lat/lngs使用CLLocationDegrees类型。如果那是准确的CoreLocation给你那是一个accuarate，它将会得到!

#4

No it will not, because the lat/long iOS will use is also a double.

不，它不会，因为lat/long的iOS将使用的也是double。

/*
 *  CLLocationDegrees
 *  
 *  Discussion:
 *    Type used to represent a latitude or longitude coordinate in degrees under the WGS 84 reference
 *    frame. The degree can be positive (North and East) or negative (South and West).  
 */
typedef double CLLocationDegrees;

#1