MKErrorDomain error 4 iPhone

Question

I keep getting this randomly when I run my gps app I'm building. It doesn't happen everytime, and the coordinates passed in are always valid (i nslog them). Is there documentation for these somewhere?

EDIT:

CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(locManager.location.coordinate.latitude, locManager.location.coordinate.longitude);
geocoder1 = [[MKReverseGeocoder alloc] initWithCoordinate:coord];
geocoder1.delegate = self;
[geocoder1 start];

and then about half the time it returns an error. I tried releasing and re-assigning the geocoder if there was an error, but that didn't help. Only thing that did was restarting the app.

Answer 1

I've met and solved this issue recently. In my case, when Apple Map cannot find any result for a query, it sometimes will just throw this this "MKErrorDomain = 4" error. So I ended up just treat this as "result not found".

It was painstaking to find this out, MapKit needs a better Error handling system.

Answer 2

In "MKTypes.h" in the MapKit framework, the following is defined:

Error constants for the Map Kit framework.

enum MKErrorCode {
   MKErrorUnknown = 1,
   MKErrorServerFailure,
   MKErrorLoadingThrottled,
   MKErrorPlacemarkNotFound,
};

...

MKErrorPlacemarkNotFound

The specified placemark could not be found.

This sounds like you are referencing some unknown placemark in your code? Or it could be that Google doesn't have a name for the position you are passing - however valid the coordinates may be.

Answer 3

I've been hitting this error repeatedly, and was unable to figure out how to make it stop; but I finally found an end-run around the whole issue that works quite well, and only takes a little more work: Don't use Apple's MKReverseGeocoder at all -- instead, directly call Google's reverse-geocoding API (this is apparently the same service that MKReverseGeocoder does behind the scenes). You can get back either JSON or XML (your preference), which you will then have to parse, but that isn't too hard.

For example, since my app is using ASIHTTPRequest, this is what it looks like (although this would also be easy to do with do with Apple's native APIs such as NSURLConnection):

#pragma mark -
#pragma mark CLLocationManagerDelegate

- (void)locationManager:(CLLocationManager *)manager 
    didUpdateToLocation:(CLLocation *)newLocation 
           fromLocation:(CLLocation *)oldLocation
{
    // Be careful: My code is passing sensor=true, because I got the lat/long
    // from the iPhone's location services, but if you are passing in a lat/long
    // that was obtained by some other means, you must pass sensor=false.
    NSString* urlStr = [NSString stringWithFormat:
      @"http://maps.googleapis.com/maps/api/geocode/xml?latlng=%f,%f&sensor=true",
      newLocation.coordinate.latitude, newLocation.coordinate.longitude];
    NSURL* url = [NSURL URLWithString:urlStr];
    self.reverseGeocoderRequest = [ASIHTTPRequest requestWithURL:url];
    self.reverseGeocoderRequest.delegate = self;
    [self.reverseGeocoderRequest startAsynchronous];
}

By the way, Google's API has rules, just like Apple's does. Make sure you read the docs, especially regarding quotas.

Answer 4

I'm running into the same thing (the exact same code randomly fails sometimes) and I think I've found the answer. From Apple's developer docs: "Each Map Kit application has a limited amount of reverse geocoding capacity, so it is to your advantage to use reverse geocode requests sparingly."

So my theory is, we're getting rate-limited... since no other variables are changing (i.e. my code isn't changing, I'm running it on the simulator so the location of the device isn't changing, etc.) I think this must be the only remaining reason.