StackOverflow2013

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POTrouble finding location with iPhone in urban environments
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copied!<p>We are developing an iPhone app and need to know the user's approximate location. We are using CoreLocation. We can do it ok in suburban environments, but in New York City - we're not able to get any longitude/latitude info.</p> <p>We suspect it's cos GPS signals are weak among highrises... But shouldn't we still be able to get some approximate location info back?</p> <p>Any ideas on what may cause/fix this? Thanks.</p> <pre><code>#import "RootViewController.h" #import "SlickEatsAppDelegate.h" #import "SlickEatsWelcomePage.h" #import "XMLParserShowTodaysOffer.h" #import "SlickEatsSplashScreen.h" @implementation RootViewController @synthesize locationManager,currentLocation,appDelegate; @synthesize getStartedButton,splashLogoImageView,howItWorkImageView,workButton,infoView; @synthesize xmlParserShowTodaysOffer;//activityIndicator #pragma mark - #pragma mark View lifecycle - (void)viewDidLoad { [super viewDidLoad]; [self connectedToNetwork]; self.navigationController.navigationBar.hidden = TRUE; if(locationManager == nil) { [[self locationManager] startUpdatingLocation]; } //[self.view addSubview:SlickEatsView]; // Uncomment the following line to display an Edit button in the navigation bar for this view controller. // self.navigationItem.rightBarButtonItem = self.editButtonItem; } - (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; } /*-(IBAction)getStartedButton_Clicked:(id)sender { activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge]; self.activityIndicator.frame = CGRectMake(135, 150, 40, 40); [self.view addSubview:activityIndicator]; if (self.activityIndicator.isAnimating == NO) { [self.activityIndicator startAnimating]; } /*if(locationManager == nil) { [[self locationManager] startUpdatingLocation]; }*/ /*SlickEatsWelcomePage *welcomePage = [[SlickEatsWelcomePage alloc]initWithNibName:@"SlickEatsWelcomePage" bundle:nil]; appDelegate = (SlickEatsAppDelegate *)[[UIApplication sharedApplication]delegate]; xmlParserShowTodaysOffer = [XMLParserShowTodaysOffer alloc]; xmlParserShowTodaysOffer.currentCity = appDelegate.myCurrentCity; xmlParserShowTodaysOffer.currentLatitude = appDelegate.myCurrentLatitude; xmlParserShowTodaysOffer.currentLongitude = appDelegate.myCurrentLongitude; [xmlParserShowTodaysOffer initXMLParser]; [xmlParserShowTodaysOffer release]; [self.navigationController pushViewController:welcomePage animated:YES]; [welcomePage release]; [activityIndicator removeFromSuperview]; //[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"9763912503"]]; }*/ - (CLLocationManager *)locationManager { locationManager = [[CLLocationManager alloc] init]; locationManager.delegate = self; locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters; // 100 m [locationManager startUpdatingLocation]; return locationManager; } #pragma mark - #pragma mark CLLocationManagerDelegate Methods - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation { appDelegate = (SlickEatsAppDelegate *)[[UIApplication sharedApplication]delegate]; int degrees = newLocation.coordinate.latitude; double decimal = fabs(newLocation.coordinate.latitude - degrees); int minutes = decimal * 60; double seconds = decimal * 3600 - minutes * 60; NSString *lat = [NSString stringWithFormat:@"%d° %d' %1.4f\"", degrees, minutes, seconds]; //latLabel.text = lat; NSLog(@"Current..Latitude::%@",lat); NSString *CurrentLatitude = [NSString stringWithFormat:@"%lf",newLocation.coordinate.latitude]; NSLog(@"Current..Latitude::%@",CurrentLatitude); //self.myCurrentLatitude=lat; degrees = newLocation.coordinate.longitude; decimal = fabs(newLocation.coordinate.longitude - degrees); minutes = decimal * 60; seconds = decimal * 3600 - minutes * 60; NSString *longt = [NSString stringWithFormat:@"%d° %d' %1.4f\"", degrees, minutes, seconds]; //longLabel.text = longt; NSLog(@"Current..Longitude::%@",longt); NSString *CurrentLongitude = [NSString stringWithFormat:@"%lf",newLocation.coordinate.longitude]; NSLog(@"Current..Longitude::%@",CurrentLongitude); appDelegate.myCurrentLatitude = CurrentLatitude; appDelegate.myCurrentLongitude = CurrentLongitude; MKReverseGeocoder *geoCoder = [[MKReverseGeocoder alloc] initWithCoordinate:newLocation.coordinate]; geoCoder.delegate = self; [geoCoder start]; } // this delegate is called when the reverseGeocoder finds a placemark - (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFindPlacemark:(MKPlacemark *)placemark { MKPlacemark * myPlacemark = placemark; // with the placemark you can now retrieve the city name NSString *city =[ myPlacemark.addressDictionary objectForKey:(NSString*) kABPersonAddressCityKey]; // NSString *city = (NSString *)[myPlacemark.locality length]; NSLog(@"Current Add::%@",city); appDelegate.myCurrentCity = city; //[self sendLocation]; } // this delegate is called when the reversegeocoder fails to find a placemark - (void)reverseGeocoder:(MKReverseGeocoder *)geocoder didFailWithError:(NSError *)error { NSLog(@"reverseGeocoder:%@ didFailWithError:%@", geocoder, error); } - (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error { NSLog(@"error%@",error); switch([error code]) { case kCLErrorNetwork: // general, network-related error { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"please check your network connection or that you are not in airplane mode" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil]; [alert show]; [alert release]; } break; case kCLErrorDenied:{ UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"user has denied to use current Location " delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil]; [alert show]; [alert release]; } break; default: { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" message:@"unknown network error" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil]; [alert show]; [alert release]; } break; } } -(void)sendLocation { NSLog(@"in Send Location.."); SlickEatsWelcomePage *welcomePage = [[SlickEatsWelcomePage alloc]initWithNibName:@"SlickEatsWelcomePage" bundle:nil]; appDelegate = (SlickEatsAppDelegate *)[[UIApplication sharedApplication]delegate]; xmlParserShowTodaysOffer = [XMLParserShowTodaysOffer alloc]; xmlParserShowTodaysOffer.currentCity = appDelegate.myCurrentCity; xmlParserShowTodaysOffer.currentLatitude = appDelegate.myCurrentLatitude; xmlParserShowTodaysOffer.currentLongitude = appDelegate.myCurrentLongitude; [xmlParserShowTodaysOffer initXMLParser]; [xmlParserShowTodaysOffer release]; [self.navigationController pushViewController:welcomePage animated:YES]; [welcomePage release]; //[locationManager release]; } -(IBAction)workButton_clicked:(id)sender { /*activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge]; self.activityIndicator.frame = CGRectMake(135, 150, 40, 40); [self.splashLogoImageView addSubview:activityIndicator]; if (self.activityIndicator.isAnimating == NO) { [self.activityIndicator startAnimating]; }*/ SlickEatsSplashScreen *intro = [[SlickEatsSplashScreen alloc]initWithNibName:@"SlickEatsSplashScreen" bundle:nil]; [self.navigationController pushViewController:intro animated:YES]; [intro release]; //[activityIndicator removeFromSuperview]; } - (void)connectedToNetwork { BOOL aflag= ([NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.co.in/"]]!=NULL)?YES:NO; if (!aflag) { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:nil message:@"Sorry!....You are not connected to network " delegate:self cancelButtonTitle:@"Exit" otherButtonTitles:nil]; [alert show]; [alert release]; } } /* - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; } */ /* - (void)viewWillDisappear:(BOOL)animated { [super viewWillDisappear:animated]; } */ /* - (void)viewDidDisappear:(BOOL)animated { [super viewDidDisappear:animated]; } */ /* // Override to allow orientations other than the default portrait orientation. - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { // Return YES for supported orientations. return (interfaceOrientation == UIInterfaceOrientationPortrait); } */ /* // Override to support conditional editing of the table view. - (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath { // Return NO if you do not want the specified item to be editable. return YES; } */ /* // Override to support editing the table view. - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath { if (editingStyle == UITableViewCellEditingStyleDelete) { // Delete the row from the data source. [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; } else if (editingStyle == UITableViewCellEditingStyleInsert) { // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view. } } */ /* // Override to support rearranging the table view. - (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath { } */ /* // Override to support conditional rearranging of the table view. - (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath { // Return NO if you do not want the item to be re-orderable. return YES; } */ #pragma mark - #pragma mark Memory management - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Relinquish ownership any cached data, images, etc that aren't in use. } - (void)viewDidUnload { // Relinquish ownership of anything that can be recreated in viewDidLoad or on demand. // For example: self.myOutlet = nil; } - (void)dealloc { [super dealloc]; [workButton release]; [howItWorkImageView release]; [splashLogoImageView release]; [getStartedButton release]; [locationManager release]; } @end </code></pre>

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