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社区首页 >问答首页 >快速计算两个地点之间的距离

快速计算两个地点之间的距离
EN

Stack Overflow用户
提问于 2017-09-03 18:28:17
回答 3查看 7.2K关注 0票数 3

我想知道两个地点之间的距离。我试过这个代码:

代码语言:javascript
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func mapView(_ mapView: MKMapView, didUpdate userLocation: MKUserLocation) {
   CLGeocoder().geocodeAddressString("ADDRESS OF LOC 2") {    (placemarks, error) in
   guard let placemarks = placemarks, let loc2 = placemarks.first?.location
      else {
         return
      }


    let loc1 = CLLocation(latitude: userLocation.coordinate.latitude, longitude: userLocation.coordinate.longitude)

    var distance = loc1.distance(from: loc2)
    print((distance/1000).rounded(), " km")
     }
}

我的问题是我的距离不对。打印结果为"2公里“。

如果计算“地图”中相同位置之间的距离,就可以得到长度为"2,7公里“和"2,9公里”的两条路线选择

我做错什么了?

EN

回答 3

Stack Overflow用户

回答已采纳

发布于 2017-09-03 18:36:37

来自文献资料

这种方法通过跟踪沿地球曲率的两处之间的一条线来测量这两个位置之间的距离。所产生的弧线是一条平滑的曲线,没有考虑到两个位置之间的特定高度变化。

所以你在计算直线距离,“当乌鸦飞”,而不是沿着道路,这会导致一个更长的路线,就像你在地图上看到的。您需要像MapKit的MKDirectionsRequest这样的东西来匹配在Maps应用程序中看到的路径。雷·温德利希有一个很好的教程。

下面是我刚刚介绍的一个在macOS游乐场上工作的例子:

代码语言:javascript
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//: Playground - noun: a place where people can play

import Cocoa
import MapKit
import CoreLocation

// As we're waiting for completion handlers, don't want the playground
// to die on us just because we reach the end of the playground.
// See https://stackoverflow.com/questions/40269573/xcode-error-domain-dvtplaygroundcommunicationerrordomain-code-1
import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true

let geocoder = CLGeocoder()
geocoder.geocodeAddressString("1 Pall Mall East, London SW1Y 5AU") { (placemarks: [CLPlacemark]? , error: Error?) in
    if let placemarks = placemarks {
        let start_placemark = placemarks[0]
        geocoder.geocodeAddressString("Buckingham Palace, London SW1A 1AA", completionHandler: { ( placemarks: [CLPlacemark]?, error: Error?) in
            if let placemarks = placemarks {
                let end_placemark = placemarks[0]

                // Okay, we've geocoded two addresses as start_placemark and end_placemark.
                let start = MKMapItem(placemark: MKPlacemark(coordinate: start_placemark.location!.coordinate))
                let end = MKMapItem(placemark: MKPlacemark(coordinate: end_placemark.location!.coordinate))

                // Now we've got start and end MKMapItems for MapKit, based on the placemarks. Build a request for 
                // a route by car.
                let request: MKDirectionsRequest = MKDirectionsRequest()
                request.source = start
                request.destination = end
                request.transportType = MKDirectionsTransportType.automobile

                // Execute the request on an MKDirections object
                let directions = MKDirections(request: request)
                directions.calculate(completionHandler: { (response: MKDirectionsResponse?, error: Error?) in
                    // Now we should have a route.
                    if let routes = response?.routes {
                        let route = routes[0]
                        print(route.distance) // 2,307 metres.
                    }
                })
            }
        })
    }
}
票数 3
EN

Stack Overflow用户

发布于 2017-09-03 19:43:37

如果你想要旅行的距离而不是“像乌鸦一样飞”,可以使用MKDirections,例如:

代码语言:javascript
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func routes(to item: MKMapItem, completion: @escaping ([MKRoute]?, Error?) -> Void) {
    let request = MKDirections.Request()
    request.source = MKMapItem.forCurrentLocation()
    request.destination = item
    request.transportType = .automobile

    let directions = MKDirections(request: request)
    directions.calculate { response, error in
        completion(response?.routes, error)
    }
}

如果您想将小数点格式设置为小数位,我建议使用NumberFormatter,因此对于那些十进制分隔符不是.的国际用户来说,它的格式是适当的

代码语言:javascript
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self.routes(to: item) { routes, error in
    guard let routes = routes, error == nil else {
        print(error?.localizedDescription ?? "Unknown error")
        return
    }

    let formatter = NumberFormatter()
    formatter.numberStyle = .decimal
    formatter.minimumFractionDigits = 1
    formatter.maximumFractionDigits = 1

    for route in routes {
        let distance = route.distance / 1000
        print(formatter.string(from: NSNumber(value: distance))!, "km")
    }
}
票数 2
EN

Stack Overflow用户

发布于 2020-03-18 08:01:02

使用MapKit和Swift 5

计算两个位置之间的距离,它将帮助任何人

示例功能:我在Google和Apple中进行了测试

代码语言:javascript
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        let startLocation : CLLocation = CLLocation.init(latitude: 23.0952779, longitude: 72.5274129)
        let endLocation : CLLocation = CLLocation.init(latitude: 23.0981711, longitude: 72.5294229)
        let distance = startLocation.distance(from: endLocation)
        self.getDistance(departureDate: Date().adjust(hour: 8, minute: 0, second: 0, day: 0, month: 0), arrivalDate: Date().adjust(hour: 8, minute: 10, second: 0, day: 0, month: 0), startLocation: startLocation, endLocation: endLocation) { (distanceInMeters) in

            print("fake distance: \(distance)")
            let fakedistanceInMeter = Measurement(value: distance, unit: UnitLength.meters)
            let fakedistanceInKM = fakedistanceInMeter.converted(to: UnitLength.kilometers).value
            let fakedistanceInMiles = fakedistanceInMeter.converted(to: UnitLength.miles).value
            print("fakedistanceInKM :\(fakedistanceInKM)")
            print("fakedistanceInMiles :\(fakedistanceInMiles)")


            print("actualDistance : \(distanceInMeters)")

            let distanceInMeter = Measurement(value: distanceInMeters, unit: UnitLength.meters)
            let distanceInKM = distanceInMeter.converted(to: UnitLength.kilometers).value
            let distanceInMiles = distanceInMeter.converted(to: UnitLength.miles).value
            print("distanceInKM :\(distanceInKM)")
            print("distanceInMiles :\(distanceInMiles)")
        }

职能的使用

代码语言:javascript
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                    self.getDistance(departureDate: trip.departure.dateTime, arrivalDate: trip.arrival.dateTime, startLocation: startLocation, endLocation: endLocation) { (actualDistance) in
                        print("actualDistance : \(actualDistance)")
                    }

我对上面的函数进行了改进,并在这里添加了代码,希望它能帮助到一些人.

代码语言:javascript
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func calculateDistancefrom(departureDate: Date, arrivalDate: Date, sourceLocation: MKMapItem, destinationLocation: MKMapItem, doneSearching: @escaping (_ distance: CLLocationDistance) -> Void) {

        let request: MKDirections.Request = MKDirections.Request()

        request.departureDate = departureDate
        request.arrivalDate = arrivalDate

        request.source = sourceLocation
        request.destination = destinationLocation

        request.requestsAlternateRoutes = true
        request.transportType = .automobile

        let directions = MKDirections(request: request)
        directions.calculate { (directions, error) in
            if var routeResponse = directions?.routes {
                routeResponse.sort(by: {$0.expectedTravelTime <
                    $1.expectedTravelTime})
                let quickestRouteForSegment: MKRoute = routeResponse[0]

                doneSearching(quickestRouteForSegment.distance)
            }
        }
    }

    func getDistance(departureDate: Date, arrivalDate: Date, startLocation : CLLocation, endLocation : CLLocation, completionHandler: @escaping (_ distance: CLLocationDistance) -> Void) {

        let destinationItem =  MKMapItem(placemark: MKPlacemark(coordinate: startLocation.coordinate))
        let sourceItem      =  MKMapItem(placemark: MKPlacemark(coordinate: endLocation.coordinate))
        self.calculateDistancefrom(departureDate: departureDate, arrivalDate: arrivalDate, sourceLocation: sourceItem, destinationLocation: destinationItem, doneSearching: { distance in
            completionHandler(distance)
        })
    }
票数 0
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页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/46026591

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