title: How to check validity of CLLocation in iOS
body: <p>How to check validity of <code>CLLocation</code> in iOS?</p>
  
  <p>In fact this is my situation,</p>
  
  <p>I just create a new map</p>
  
  <pre><code>mapView = [[MKMapView alloc] initWithFrame:CGRectMake(10, 30, 300, 380)];
  mapView.showsUserLocation = YES;
  [mapView setDelegate:self];
  </code></pre>
  
  <p>And then I want to check the validity of the user location</p>
  
  <pre><code>mapView.userLocation.location 
  </code></pre>
  
  <p>Since I get this error when using the user location</p>
  
  <pre><code>'NSInvalidArgumentException', reason: 'Invalid Coordinate -180.00000000, -180.00000000'
  </code></pre>
  
  <p>Thanks in advance~</p>