Finding the compass orientation of an iPhone in swift

Question

I'm trying to make an app which is similar to a compass, but with notable differences, however, they are not important. What I need to know is: how can I get the iPhone to give me the compass orientation (i.e. 0 degrees for north) regardless of the phone's orientation (i.e. It will give the same reading if it is lying flat on a table or portrait in someone's hand if it is pointing the same way)

TL;DR How can I get an iPhone's rotation around the y axis which updates every second or so.

score 26 · Accepted Answer · answered Jun 08 '15 at 09:27

26

import CoreLocation

class ViewController: UIViewController ,CLLocationManagerDelegate {

    var lm:CLLocationManager!

    override func viewDidLoad() {
        super.viewDidLoad()

        lm = CLLocationManager()
        lm.delegate = self

        lm.startUpdatingHeading()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    func locationManager(manager: CLLocationManager!, didUpdateHeading newHeading: CLHeading!) {
        println(newHeading.magneticHeading)
    }
}

You can get more information from https://developer.apple.com/library/ios/documentation/CoreLocation/Reference/CLHeading_Class/

answered Jun 08 '15 at 09:27

Reming Hsu

2,215
15
18

I have tried this both in sim and on device and I can't get any heading values to show. I have it tied to a label that should update when I walk around outside. Any ideas? – Ethan Parker Jan 15 '19 at 19:14
1

Good answer, but I can’t think of a reason to implement `didReceiveMemoryWarning()` and just call `super` — I mean, that’s the default behavior. – Wil Shipley Sep 04 '19 at 01:50

score 10 · Answer 2 · answered Feb 06 '17 at 11:01

Swift 3:

import UIKit
import CoreLocation

class ViewController: UIViewController, CLLocationManagerDelegate {

    let locationManager = CLLocationManager()

    override func viewDidLoad() {
        super.viewDidLoad()

       // Azimuth
        if (CLLocationManager.headingAvailable()) {
            locationManager.headingFilter = 1
            locationManager.startUpdatingHeading()
            locationManager.delegate = self
        }
    }

    func locationManager(_ manager: CLLocationManager, didUpdateHeading heading: CLHeading) {
        print (heading.magneticHeading)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

I've got this code exactly as you show it here in my app, but in the simulator with a location path turned on I never get any headings print out — David Findlay, Jun 10 '17 at 03:35
Magnectic heading is not supported in simulator try in a real device. — Sébastien REMY, Jun 11 '17 at 10:43

score 5 · Answer 3 · edited Sep 11 '18 at 12:59

Swift 3.0

    import UIKit
    import CoreLocation

    class ViewController: UIViewController, CLLocationManagerDelegate {

    @IBOutlet weak var compass: UIImageView!
    @IBOutlet weak var angleLabel: UILabel!
    @IBOutlet weak var geographicalDirectionLabel: UILabel!

    var locationManager = CLLocationManager()

    override func viewDidLoad() {

        super.viewDidLoad()


        locationManager.delegate = self

        // Start location services to get the true heading.
        locationManager.distanceFilter = 1000
        locationManager.desiredAccuracy = kCLLocationAccuracyKilometer
        locationManager.startUpdatingLocation()

        //Start heading updating.
        if CLLocationManager.headingAvailable() {
            locationManager.headingFilter = 5
            locationManager.startUpdatingHeading()
        }




    }

    func locationManager(_ manager: CLLocationManager, didUpdateHeading newHeading: CLHeading) {

        if newHeading.headingAccuracy < 0 {
            return
        }

        // Get the heading(direction)
        let heading: CLLocationDirection = ((newHeading.trueHeading > 0) ?
            newHeading.trueHeading : newHeading.magneticHeading);
        UIView.animate(withDuration: 0.5) {
            let angle = CGFloat(heading).toRadians // convert from degrees to radians
            self.compass.transform = CGAffineTransform(rotationAngle: angle) // rotate the picture
        }
        print(heading)
        angleLabel.text = String(format: "%0.2f", heading)

       var strDirection = String()
        if(heading > 23 && heading <= 67){
            strDirection = "North East";
        } else if(heading > 68 && heading <= 112){
            strDirection = "East";
        } else if(heading > 113 && heading <= 167){
            strDirection = "South East";
        } else if(heading > 168 && heading <= 202){
            strDirection = "South";
        } else if(heading > 203 && heading <= 247){
            strDirection = "South West";
        } else if(heading > 248 && heading <= 293){
            strDirection = "West";
        } else if(heading > 294 && heading <= 337){
            strDirection = "North West";
        } else if(heading >= 338 || heading <= 22){
            strDirection = "North";
        }

        geographicalDirectionLabel.text = strDirection
    }
  }

thanks for this answer, does trueHeading gives real value related to north? — user924, Mar 13 '18 at 07:15

Finding the compass orientation of an iPhone in swift

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