Altitude problem IOS

问题:

I have a problem in getting the altitude , it returns 0.0000 . Here is my code:

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
NSString *tAltitude  = [NSString stringWithFormat:@"%f", [newLocation altitude]];
CLLocationCoordinate2D coord=newLocation.coordinate;
MKCoordinateSpan span = {.latitudeDelta =  0.005, .longitudeDelta =  0.005};
MKCoordinateRegion region = {coord, span};
[map setRegion:region];
NSLog(@"Location: %@", [newLocation description]);
NSLog(@"altitudine:%@",tAltitude); }

回答1:

If you are indoor, iPhone uses cell tower, or WIFI location. These location will not return altitude. You have to test outdoor to get GPS.

To make sure that you are using GPS, check the horizontal accuracy as well. If it is in the range of 2 digits, you should be on GPS, and most likely you will get altitude reading