ios distanceFromLocation - 计算两点之间的距离

distanceFromLocation - Calculate distance between two points

提问by Stephen

Just a quick question on Core Location, I'm trying to calculate the distance between two points, code is below:

只是一个关于核心位置的快速问题，我正在尝试计算两点之间的距离，代码如下：

    -(void)locationChange:(CLLocation *)newLocation:(CLLocation *)oldLocation
    {   

    // Configure the new event with information from the location.
        CLLocationCoordinate2D newCoordinate = [newLocation coordinate];
        CLLocationCoordinate2D oldCoordinate = [oldLocation coordinate];

        CLLocationDistance kilometers = [newCoordinate distanceFromLocation:oldCoordinate] / 1000; // Error ocurring here.
        CLLocationDistance meters = [newCoordinate distanceFromLocation:oldCoordinate]; // Error ocurring here.
}

I'm getting the following error on the last two lines:

我在最后两行收到以下错误：

error: cannot convert to a pointer type

错误：无法转换为指针类型

I've been searching Google, but I cannot find anything.

我一直在谷歌搜索，但我找不到任何东西。

回答by deanWombourne

Try this instead:

试试这个：

CLLocationDistance meters = [newLocation distanceFromLocation:oldLocation];

The method you're trying to use is a method on a CLLocationobject :)

您尝试使用的方法是CLLocation对象上的方法:)

回答by Atulkumar V. Jain

The distance is calculated between 2 CLLocations and not between to coordinates.

距离是在 2 个 CLLocations 之间计算的，而不是在坐标之间计算的。

You need to use these coordinates to get the CLLocations for the respective coordinates using the following line of code

您需要使用这些坐标来使用以下代码行获取相应坐标的 CLLocations

CLLocation *newLocation = [[CLLocation alloc] initWithCoordinate: newCoordinate altitude:1 horizontalAccuracy:1 verticalAccuracy:-1 timestamp:nil];

Similarly for the other coordinate and then you can calculate the distance between these two locations using the following line of code

同样对于另一个坐标，然后您可以使用以下代码行计算这两个位置之间的距离

CLLocationDistance kilometers = [newLocation distanceFromLocation:oldLocation] / 1000;

Hope this will help you.

希望这会帮助你。

Update:Swift 3.0

更新：Swift 3.0

let distanceKiloMeters = (newLocation.distance(from: oldLocation))/1000

回答by Atulkumar V. Jain

In Swift

在斯威夫特

Let's create a method function that calculates distance between two locations:

让我们创建一个方法函数来计算两个位置之间的距离：

 func distanceBetweenTwoLocations(source:CLLocation,destination:CLLocation) -> Double{

        var distanceMeters = source.distanceFromLocation(destination)
        var distanceKM = distanceMeters / 1000
        let roundedTwoDigit = distanceKM.roundedTwoDigit
        return roundedTwoDigit

    }

If you want only two digits:

如果你只想要两位数：

extension Double{

    var roundedTwoDigit:Double{

        return Double(round(100*self)/100)

        }
    }

回答by Max Alexander

If you're going to do with 2 CLLocationCoordinate2D values then you can use this.

如果您打算使用 2 个 CLLocationCoordinate2D 值，那么您可以使用它。

This is Swift 2.1 on Xcode 7.1

这是 Xcode 7.1 上的 Swift 2.1

import CoreLocation

extension CLLocationCoordinate2D {

    func distanceInMetersFrom(otherCoord : CLLocationCoordinate2D) -> CLLocationDistance {
        let firstLoc = CLLocation(latitude: self.latitude, longitude: self.longitude)
        let secondLoc = CLLocation(latitude: otherCoord.latitude, longitude: otherCoord.longitude)
        return firstLoc.distanceFromLocation(secondLoc)
    }

}

回答by Yogesh Tarsariya

#import <CoreLocation/CoreLocation.h>

CLLocation *locA = [[CLLocation alloc] initWithLatitude:"Value" longitude:"Value"];

CLLocation *locB = [[CLLocation alloc] initWithLatitude:"Value" longitude:"Value"];

CLLocationDistance distance = [locA distanceFromLocation:locB];
NSLog(@"distance:-%f",distance);//distance in Miter

回答by Pawel

The problem here is that you're calling an object method:

这里的问题是您正在调用对象方法：

- (CLLocationDistance)distanceFromLocation:(const CLLocation *)location;

of class CLLocation.

CLLocation 类的。

CLLocationCoordinate2D is in fact a structure, consisting of two doubles:

CLLocationCoordinate2D 实际上是一个结构体，由两个双精度组成：

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

Proper way of doing this is to get a CLLocationobject and call distanceFromLocationon it. Like this:

正确的做法是获取一个CLLocation对象并调用distanceFromLocation它。像这样：

CLLocation* newLocation;
CLLocation* oldLocation;
CLLocationDistance distance = [newLocation distanceFromLocation:oldLocation];

Of course you first need to initialize both of those values (from CLLocationManager, for instance).

当然，您首先需要初始化这两个值（CLLocationManager例如from ）。

回答by zerodog

Taken from the excellent libary CoreLocation utitlities:

取自优秀的库CoreLocation 实用程序：

- (CLLocationDistance) distanceFromCoordinate:(CLLocationCoordinate2D) fromCoord;
{
    double earthRadius = 6371.01; // Earth's radius in Kilometers

    // Get the difference between our two points then convert the difference into radians
    double nDLat = (fromCoord.latitude - self.coordinate.latitude) * kDegreesToRadians;  
    double nDLon = (fromCoord.longitude - self.coordinate.longitude) * kDegreesToRadians; 

    double fromLat =  self.coordinate.latitude * kDegreesToRadians;
    double toLat =  fromCoord.latitude * kDegreesToRadians;

    double nA = pow ( sin(nDLat/2), 2 ) + cos(fromLat) * cos(toLat) * pow ( sin(nDLon/2), 2 );

    double nC = 2 * atan2( sqrt(nA), sqrt( 1 - nA ));
    double nD = earthRadius * nC;

    return nD * 1000; // Return our calculated distance in meters
}