从每米秒快速获取每公里分钟数

Question

I have an array of CLLocations each with the seconds per meter element. I want to calculate the run splits from that array (Minutes per kilometer). How can I fetch the minutes per kilometer for each kilometer from the CLLocations array?

This is how I am getting the locations below.

let query = HKWorkoutRouteQuery(route: route) { (_, locations, _, error) in
        if let error = error {
            print("There was an error fetching route data: ", error)
            return
        }

        guard let locations = locations else { return }
    }
    healthStore.execute(query)

Answer 1

CLLocationSpeed is defined as speed in meters per second, see Apple Docs

It is an alias for Double , so you can just translate it with:

let speedMS = location.speed
let speedKMM = speedMS * 3 / 50

You can use an extension for better code readability:

extension CLLocationSpeed {
    func toKmM() -> Double {
        return self * 3 / 50
    }
}

And when you want to get km/m, you just use CLLocation.speed.toKmM()

Edit:
And even simpler solution by @Leo Dabus, extend CLLocation:

extension CLLocation { 
    var kilometersPerMinute: Double { 
        speed * 0.06 
    } 
}

Answer 2

You can also create your own speed unit extending UnitSpeed. The advantage of doing it this way is that you can associate a symbol and gain much more control over the conversions:

extension UnitSpeed {
    static var metersPerMinute: UnitSpeed = .init(symbol: "m/min", converter:  UnitConverterLinear(coefficient: 1 / 60))
    static var kilometersPerMinute: UnitSpeed = .init(symbol: "km/min", converter:  UnitConverterLinear(coefficient: 50 / 3))
}

---

let metersPerSecond = Measurement<UnitSpeed>(value: 30, unit: .metersPerSecond)
let kilometersPerHour = metersPerSecond.converted(to: .kilometersPerHour)      // 107.9999136000691 km/h
let kilometersPerMinute = metersPerSecond.converted(to: .kilometersPerMinute)  // 1.7999999999999998 km/min
let formatter = MeasurementFormatter()
formatter.unitStyle = .medium
formatter.unitOptions = .providedUnit
formatter.numberFormatter.maximumFractionDigits = 1
formatter.string(from: kilometersPerHour)      // "108 km/h"
formatter.string(from: kilometersPerMinute)    // "1.8 km/min"

UnitSpeed.kilometersPerMinute.converter.value(fromBaseUnitValue: 1) // 0.06