ios - CLLocationManager: Unexpectedly Found Nil While Unwrapping an Optional Value -

here's code in viewcontroller.swift:

import uikit import alamofire import swiftyjson import mapkit import corelocation import twitterkit  class viewcontroller: uiviewcontroller, mkmapviewdelegate, cllocationmanagerdelegate {      @iboutlet weak var mymap: mkmapview!     @iboutlet weak var counterlabel: uilabel!      var manager = cllocationmanager()      override func viewdidload() {         super.viewdidload()          // additional setup after loading view, typically nib.          //calling cllocation         manager.delegate = self         manager.desiredaccuracy = kcllocationaccuracybest         manager.requestwheninuseauthorization()         manager.startupdatinglocation()          //map region         let locationzoom = self.manager.location         var latitude: double = locationzoom.coordinate.latitude         var longitude: double = locationzoom.coordinate.longitude         var centerlatitude: cllocationdegrees = locationzoom.coordinate.latitude         var centerlongitude: cllocationdegrees = locationzoom.coordinate.longitude         var latdelta: cllocationdegrees = 0.03         var longdelta: cllocationdegrees = 0.03         var span: mkcoordinatespan = mkcoordinatespanmake(latdelta, longdelta)         var location: cllocationcoordinate2d = cllocationcoordinate2dmake(centerlatitude, centerlongitude)         var region: mkcoordinateregion = mkcoordinateregionmake(location, span) // creates map region center         mymap.setregion(region, animated: true)     }      @ibaction func zoom(sender: anyobject) {           let locationzoom = self.manager.location          var latitude: double = locationzoom.coordinate.latitude         var longitude: double = locationzoom.coordinate.longitude         var centerlatitude:cllocationdegrees = locationzoom.coordinate.latitude         var centerlongitude: cllocationdegrees = locationzoom.coordinate.longitude         var latdelta:cllocationdegrees = 0.03         var longdelta:cllocationdegrees = 0.03         var span:mkcoordinatespan = mkcoordinatespanmake(latdelta, longdelta)         var location:cllocationcoordinate2d = cllocationcoordinate2dmake(centerlatitude, centerlongitude)         var region:mkcoordinateregion = mkcoordinateregionmake(location, span) // creates map region center         mymap.setregion(region, animated: true)     } } 

now, error described thus:

fatal error: unexpectedly found nil while unwrapping optional value

thread 1 pointing towards being issue:

var latitude: double = locationzoom.coordinate.latitude 

however, when testing on simulator, have found issue occur longitude variable. still, not understand why values both longitude , latitude set "nil." have set cllocationmanager correctly, made sure modify info.plist necessary include nslocationwheninuseusagedescription , nslocationalwaysusagedescription, etc. what's going on, , how correct issue?

this happens because when view loads has not received location update. implement didupdatelocations , access location info there. if need reference can didupdatelocations

func locationmanager(manager: cllocationmanager!, didupdatelocations locations: [anyobject]!) {      let locationzoom = locations.last as! cllocation     let latitude: double = locationzoom.coordinate.latitude     let longitude: double = locationzoom.coordinate.longitude     println(latitude)     println(longitude) }