Reverse geocoding in Swift 4
I\'m attempting to write a simple method that\'s fed CLLocationDegrees and returns a CLPlacemark. Looking at Apple\'s documentation, it seems like
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import UIKit import CoreLocation import PlaygroundSupport PlaygroundPage.current.needsIndefiniteExecution = true
func geocode(latitude: Double, longitude: Double, completion: @escaping (_ placemark: [CLPlacemark]?, _ error: Error?) -> Void) { CLGeocoder().reverseGeocodeLocation(CLLocation(latitude: latitude, longitude: longitude)) { placemark, error in guard let placemark = placemark, error == nil else { completion(nil, error) return } completion(placemark, nil) } }or simply:
func geocode(latitude: Double, longitude: Double, completion: @escaping (_ placemark: [CLPlacemark]?, _ error: Error?) -> Void) { CLGeocoder().reverseGeocodeLocation(CLLocation(latitude: latitude, longitude: longitude), completionHandler: completion) }or extending CLLocation:
extension CLLocation { func geocode(completion: @escaping (_ placemark: [CLPlacemark]?, _ error: Error?) -> Void) { CLGeocoder().reverseGeocodeLocation(self, completionHandler: completion) } }
To format your place mark as a mailing address you can use Contacts framework
CNPostalAddressFormatter:import Contacts extension Formatter { static let mailingAddress: CNPostalAddressFormatter = { let formatter = CNPostalAddressFormatter() formatter.style = .mailingAddress return formatter }() } extension CLPlacemark { var mailingAddress: String? { return postalAddress?.mailingAddress } } extension CNPostalAddress { var mailingAddress: String { return Formatter.mailingAddress.string(from: self) } }
placemark
Contains an array of CLPlacemark objects. For most geocoding requests, this array should contain only one entry. However, forward-geocoding requests may return multiple placemark objects in situations where the specified address could not be resolved to a single location. If the request was canceled or there was an error in obtaining the placemark information, this parameter is nil.
For more information about the CLPlacemark properties you can check this CLPlacemark
Usage:
let location = CLLocation(latitude: -22.963451, longitude: -43.198242) location.geocode { placemark, error in if let error = error as? CLError { print("CLError:", error) return } else if let placemark = placemark?.first { // you should always update your UI in the main thread DispatchQueue.main.async { // update UI here print("name:", placemark.name ?? "unknown") print("address1:", placemark.thoroughfare ?? "unknown") print("address2:", placemark.subThoroughfare ?? "unknown") print("neighborhood:", placemark.subLocality ?? "unknown") print("city:", placemark.locality ?? "unknown") print("state:", placemark.administrativeArea ?? "unknown") print("subAdministrativeArea:", placemark.subAdministrativeArea ?? "unknown") print("zip code:", placemark.postalCode ?? "unknown") print("country:", placemark.country ?? "unknown", terminator: "\n\n") print("isoCountryCode:", placemark.isoCountryCode ?? "unknown") print("region identifier:", placemark.region?.identifier ?? "unknown") print("timezone:", placemark.timeZone ?? "unknown", terminator:"\n\n") // Mailind Address print(placemark.mailingAddress ?? "unknown") } } }
This will print
name: Morro da Saudade address1: Rua Casuarina address2: 597 neighborhood: Lagoa city: Rio de Janeiro state: RJ subAdministrativeArea: unknown zip code: 22011-040 country: Brazil isoCountryCode: BR region identifier: <-22.96345100,-43.19824200> radius 141.83 timezone: America/Sao_Paulo (current)Rua Casuarina, 597
Lagoa
Rio de Janeiro RJ
22011-040
Brazil
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There are so many questions dealing with 'reverseGeocodeLocation' on Stack Overflow, I've seen so many of them. I'm using Swift 4.2 and I thought my 'reverseGeocodeLocation' requests might be timing out. Well, this is NOT the case, when starting to move with an iPhone the 'didUpdateLocations' cycles need to mature. It can take two or more cycles before 'reverseGeocodeLocation' returns placemarks.
I wrote a simple app that uses 'reverseGeocodeLocation' until 'placemarks' are returned after repeated 'didUpdateLocations' cycles. This is my own home grown 'SampleCode'. I learned a lot from using the app, it might help others understand how reverse geocode requests work in the real world.
Please give your comments on possible improvements. This code is freely given and freely taken.
import Foundation import UIKit import CoreLocation class ViewController: UIViewController, CLLocationManagerDelegate { @IBAction func RefreshLocationButton(_ sender: Any) { self.requestingPlacemark = true self.placemarkData = nil //^Make another Placemark Request self.requestCounter = 0 self.RequestCounterLabel.text = "" self.LocationLabel.text = "" self.PlacemarkLabel.text = ""} @IBOutlet weak var LocationCounterLabel: UILabel! @IBOutlet weak var RequestCounterLabel: UILabel! @IBOutlet weak var LocationLabel: UILabel! @IBOutlet weak var PlacemarkLabel: UILabel! let locationManager = CLLocationManager() var placemarkData: CLPlacemark! var placemarkString: String! var printPlacemarkData: Bool! var didUpdateLocationsCounter: Int = 0 var requestCounter: Int = 0 var requestingPlacemark: Bool = true override func viewDidLoad() { super.viewDidLoad() if CLLocationManager.locationServicesEnabled() { locationManager.requestAlwaysAuthorization() locationManager.delegate = self //locationManager.desiredAccuracy = kCLLocationAccuracyBest locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation locationManager.startUpdatingLocation() self.RequestCounterLabel.text = "" self.LocationLabel.text = "" self.PlacemarkLabel.text = ""}} func printPlacemarks() { if printPlacemarkData { self.placemarkString = "Placemark Data:" self.placemarkString = buildPlacemarkString(item: 1) self.placemarkString = buildPlacemarkString(item: 2) self.placemarkString = buildPlacemarkString(item: 3) self.placemarkString = buildPlacemarkString(item: 4) self.placemarkString = buildPlacemarkString(item: 5) self.placemarkString = buildPlacemarkString(item: 6) self.placemarkString = buildPlacemarkString(item: 7) self.placemarkString = buildPlacemarkString(item: 8) self.placemarkString = buildPlacemarkString(item: 9) self.placemarkString = buildPlacemarkString(item: 10) self.PlacemarkLabel.text = self.placemarkString self.printPlacemarkData = false}} func buildPlacemarkString(item: Int) -> String { var elementText: String! var newString: String! switch item { case 1: elementText = "name: " + self.placemarkData.name! case 2: elementText = "subThoroughfare: " + self.placemarkData.subThoroughfare! case 3: elementText = "thoroughfare: " + self.placemarkData.thoroughfare! case 4: elementText = "postalCode: " + self.placemarkData.postalCode! case 5: elementText = "subLocality: " + self.placemarkData.subLocality! case 6: elementText = "locality: " + self.placemarkData.locality! case 7: elementText = "subAdministrativeArea: " + self.placemarkData.subAdministrativeArea! case 8: elementText = "administrativeArea: " + self.placemarkData.administrativeArea! case 9: elementText = "country: " + self.placemarkData.country! case 10: elementText = "isoCountryCode: " + self.placemarkData.isoCountryCode! default: print("Error: incorrect item number!")} newString = self.placemarkString + "\n" + elementText return newString } func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) { //location prints one time and 'didUpdateLocations' is stopped: self.didUpdateLocationsCounter = self.didUpdateLocationsCounter + 1 let labelString = String(describing: self.didUpdateLocationsCounter) self.LocationCounterLabel.text = "Location Update Counter: " + labelString if self.placemarkData == nil { //location variable: self.requestCounter = self.requestCounter + 1 let textString = String(describing: self.requestCounter) self.RequestCounterLabel.text = "Request Counter: " + textString if locations.count == 0 { self.LocationLabel.text = "Locations: There was NONE"} else { if locations.count > 0 { let coordinate2D: CLLocation = locations.first! let location = CLLocation(latitude: coordinate2D.coordinate.latitude, longitude: coordinate2D.coordinate.longitude) let printString = String(describing: location) self.LocationLabel.text = "Location: " + printString let geocoder: CLGeocoder = CLGeocoder() geocoder.reverseGeocodeLocation(location, completionHandler: {(placemarks, error) -> Void in if error != nil { let errorString = String(describing: error?.localizedDescription) print("reverse geodcode fail: \(errorString)") self.LocationCounterLabel.text = "" self.RequestCounterLabel.text = "" self.LocationLabel.text = "Reverse Geodcode fail: \(errorString)" self.PlacemarkLabel.text = "" self.requestingPlacemark = false return} else { let pm = placemarks! as [CLPlacemark] //There is ALWAYS 'placemarks' Data if pm.count > 0 { self.placemarkData = placemarks![0] self.printPlacemarkData = true self.printPlacemarks() self.requestingPlacemark = false}}})} else { if self.requestingPlacemark { self.LocationLabel.text = "Problem: There is no 'location.first'"}}}}}}And then the Storyboard UI:
Storyboard Image
View Controller Image
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<rect key="frame" x="0.0" y="0.0" width="375" height="667"/> <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/> <subviews> <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Location Counter" lineBreakMode="tailTruncation" numberOfLines="2" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="ZIg-u9-TMR"> <rect key="frame" x="16" y="20" width="343" height="20.5"/> <color key="backgroundColor" red="0.80000001190000003" green="0.80000001190000003" blue="0.80000001190000003" alpha="1" colorSpace="calibratedRGB"/> <fontDescription key="fontDescription" type="system" pointSize="17"/> <nil key="textColor"/> <nil key="highlightedColor"/> </label> <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Location Count Label" 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firstAttribute="centerX" secondItem="8bC-Xf-vdC" secondAttribute="centerX" id="A38-Nt-i3D"/> <constraint firstItem="6Tk-OE-BBY" firstAttribute="trailing" secondItem="ZIg-u9-TMR" secondAttribute="trailing" constant="16" id="Bb0-YC-oov"/> <constraint firstItem="csF-KS-xGE" firstAttribute="leading" secondItem="6Tk-OE-BBY" secondAttribute="leading" constant="16" id="FJU-ha-HkL"/> <constraint firstItem="42A-nO-tNf" firstAttribute="top" secondItem="qOc-gk-gSp" secondAttribute="bottom" constant="7.5" id="SpR-XB-MLG"/> <constraint firstItem="6Tk-OE-BBY" firstAttribute="bottom" secondItem="HgN-oB-ds0" secondAttribute="bottom" constant="59" id="Vr6-QE-230"/> <constraint firstItem="42A-nO-tNf" firstAttribute="leading" secondItem="6Tk-OE-BBY" secondAttribute="leading" constant="16" id="aHo-kJ-aCb"/> <constraint firstItem="csF-KS-xGE" firstAttribute="top" secondItem="ZIg-u9-TMR" secondAttribute="bottom" constant="7.5" id="c63-Mq-ItW"/> <constraint firstItem="6Tk-OE-BBY" firstAttribute="trailing" secondItem="csF-KS-xGE" secondAttribute="trailing" constant="16" id="dlV-Hc-8XJ"/> <constraint firstItem="qOc-gk-gSp" firstAttribute="leading" secondItem="6Tk-OE-BBY" secondAttribute="leading" constant="16" id="m5y-Q8-jxI"/> <constraint firstItem="ZIg-u9-TMR" firstAttribute="top" secondItem="6Tk-OE-BBY" secondAttribute="top" id="sdw-WQ-Bx9"/> <constraint firstItem="6Tk-OE-BBY" firstAttribute="trailing" secondItem="qOc-gk-gSp" secondAttribute="trailing" constant="16" id="woB-ig-i5v"/> </constraints> <viewLayoutGuide key="safeArea" id="6Tk-OE-BBY"/> </view> <connections> <outlet property="LocationCounterLabel" destination="ZIg-u9-TMR" id="K4g-WT-f82"/> <outlet property="LocationLabel" destination="qOc-gk-gSp" id="Cdw-bw-EWt"/> <outlet property="PlacemarkLabel" destination="42A-nO-tNf" id="dMh-bw-cRE"/> <outlet property="RequestCounterLabel" destination="csF-KS-xGE" id="ai6-zn-Toi"/> </connections> </viewController> <placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder"/> </objects> <point key="canvasLocation" x="53.600000000000001" y="66.11694152923539"/> </scene> </scenes> </document>讨论(0)
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