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使用 Mapkit 确定距离

发布于 2024-08-25 06:09:10 字数 181 浏览 4 评论 0原文

如何使用 Mapkit 确定 1000 英尺或 1/2 英里距离？某个销钉的半径或两个销钉之间的距离。

例如，我将地图以引脚 A 为中心。引脚 B、C 和 D 也位于地图上，与引脚 A 的距离不同。B 和 C 距离 A 不到 1/2 英里，但 D 距离 1 英里。我想知道 B 和 C 距离 A 不超过 1/2 英里。我该如何计算？

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左岸枫 2024-09-01 06:09:10

既然您已经声明这两个不同的点是“引脚”，我将假设您正在使用 MKPinAnnotationView （或其他一些注释视图）。如果没有，您将不得不通过其他方式获取该位置。

如果您有指向这些位置的注释对象的指针，那么您可以轻松地对它们调用 -coordinate ，从这些坐标创建 CLLocations（使用 -initWithLatitude:longitude:），然后使用方法 -getDistanceFrom 检索以米为单位的距离。从那里，可以轻松转换为英里。总而言之，代码看起来像这样：

CLLocationCoordinate2D pointACoordinate = [pointAAnnotation coordinate];
CLLocation *pointALocation = [[CLLocation alloc] initWithLatitude:pointACoordinate.latitude longitude:pointACoordinate.longitude];
CLLocationCoordinate2D pointBCoordinate = [pointBAnnotation coordinate];
CLLocation *pointBLocation = [[CLLocation alloc] initWithLatitude:pointBCoordinate.latitude longitude:pointBCoordinate.longitude];
double distanceMeters = [pointALocation getDistanceFrom:pointBLocation];
double distanceMiles = (distanceMeters / 1609.344);

您最终会得到以英里为单位的距离，并可以从那里进行比较。希望这有帮助。

Since you've stated that the two different points are "pins", I'm going to assume you're using MKPinAnnotationView (or some other annotation view). If not, you're going to have to get the location some other way.

If you have pointers to the annotation objects for these locations, then you can easily call -coordinate on them, create CLLocations from these coordinates (using -initWithLatitude:longitude:), and then use the method -getDistanceFrom to retrieve the distance in meters. From there, it's an easy conversion to miles. All told, the code would look something like this:

CLLocationCoordinate2D pointACoordinate = [pointAAnnotation coordinate];
CLLocation *pointALocation = [[CLLocation alloc] initWithLatitude:pointACoordinate.latitude longitude:pointACoordinate.longitude];
CLLocationCoordinate2D pointBCoordinate = [pointBAnnotation coordinate];
CLLocation *pointBLocation = [[CLLocation alloc] initWithLatitude:pointBCoordinate.latitude longitude:pointBCoordinate.longitude];
double distanceMeters = [pointALocation getDistanceFrom:pointBLocation];
double distanceMiles = (distanceMeters / 1609.344);

You'll end up with the distance in miles, and can compare it from there. Hope this helps.

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不必了 2024-09-01 06:09:10

getDistanceFrom 现已弃用，因此对于任何想要执行此操作的人来说，这是一个替代答案。

CLLocationCoordinate2D pointACoordinate = [pointAAnnotation coordinate];
CLLocation *pointALocation = [[CLLocation alloc] initWithLatitude:pointACoordinate.latitude longitude:pointACoordinate.longitude];  

CLLocationCoordinate2D pointBCoordinate = [pointBAnnotation coordinate];
CLLocation *pointBLocation = [[CLLocation alloc] initWithLatitude:pointBCoordinate.latitude longitude:pointBCoordinate.longitude];  

float distanceMeters = [pointALocation distanceFromLocation:pointBLocation];
float distanceMiles = (distanceMeters / 1609.344);  

[pointALocation release];
[pointBLocation release];

如上所述，您可以使用 float 而不是 double，并且如果您不需要 float 的精度，则可以将结果转换为 int > 像这样：

int distanceCastToInt = (int) [pointALocation distanceFromLocation:pointBLocation];

如果您想在注释中粗略地了解距离，int 会很方便，如下所示：

pointAAnnotation.title = @"Point A";
pointAAnnotation.subtitle = [NSString stringWithFormat: @"Distance: %im",distanceCastToInt];

例如，注释的副标题将显示“距离：50m”。

getDistanceFrom is now deprecated so here's an alternative answer for anyone looking to do this.

CLLocationCoordinate2D pointACoordinate = [pointAAnnotation coordinate];
CLLocation *pointALocation = [[CLLocation alloc] initWithLatitude:pointACoordinate.latitude longitude:pointACoordinate.longitude];  

CLLocationCoordinate2D pointBCoordinate = [pointBAnnotation coordinate];
CLLocation *pointBLocation = [[CLLocation alloc] initWithLatitude:pointBCoordinate.latitude longitude:pointBCoordinate.longitude];  

float distanceMeters = [pointALocation distanceFromLocation:pointBLocation];
float distanceMiles = (distanceMeters / 1609.344);  

[pointALocation release];
[pointBLocation release];

As above, you could use float instead of double and you could cast the results to an int if you don't require the precision of the float like so:

int distanceCastToInt = (int) [pointALocation distanceFromLocation:pointBLocation];

The int is handy if you wanted to give a rough idea of distance in the annotation like so:

pointAAnnotation.title = @"Point A";
pointAAnnotation.subtitle = [NSString stringWithFormat: @"Distance: %im",distanceCastToInt];

The subtitle of the annotation would read "Distance: 50m" for example.

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ぇ气 2024-09-01 06:09:10

这在 Swift 3 中相当于给定的答案：

let pointACoordinate = pointAAnnotation.coordinate
let pointALocation = CLLocation(latitude: pointACoordinate.latitude, longitude: pointACoordinate.longitude)
let pointBCoordinate = pointBAnnotation.coordinate
let pointBLocation = CLLocation(latitude: pointBCoordinate.latitude, longitude: pointBCoordinate.longitude)
let distanceMeters = pointALocation.distance(from: pointBLocation)
let distanceMiles = (distanceMeters / 1609.344)

This is Swift 3 equivalent of the given answer:

let pointACoordinate = pointAAnnotation.coordinate
let pointALocation = CLLocation(latitude: pointACoordinate.latitude, longitude: pointACoordinate.longitude)
let pointBCoordinate = pointBAnnotation.coordinate
let pointBLocation = CLLocation(latitude: pointBCoordinate.latitude, longitude: pointBCoordinate.longitude)
let distanceMeters = pointALocation.distance(from: pointBLocation)
let distanceMiles = (distanceMeters / 1609.344)

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