How to check validity of CLLocation in iOS

Question

How to check validity of CLLocation in iOS?

In fact this is my situation,

I just create a new map

mapView = [[MKMapView alloc] i         


        

Answer 1

To build on Anna K's explanation, it's general good practice to check the validity of a CLLocationCoordinate2DIsValid(YOURLOCATION).

If you are getting lats and longs from a web service or a SQLite database, you should check and make sure the location is valid before trying to add an annotation to the map. Here's an example of this in action:

for (int i = 0; i < [yourArray count]; i++) {

    YourOBJ *obj = [yourArray objectAtIndex:i];

    yourCLLocation2D.latitude = obj.latitude;
    yourCLLocation2D.longitude = obj.longitude;

    AnnotationPin *anno = [[AnnotationPin alloc] initWithCoordinate: yourCLLocation2D];

    if (CLLocationCoordinate2DIsValid(yourCLLocation2D))
    {
        anno.lat = obj.latitude;//Maybe you want to store lat
        anno.lon = obj.longitude;//and lon
        anno.title = obj.name//define the title
        anno.subtitle = obj.info//and subtitle for your annotation callout
        anno.yourLocation = yourCLLocation2D;//Some of these aren't necessary
        anno.tag = i;//but can really help to define and track pins

        [map addAnnotation:anno];
    }

    [anno release];
}

For all those who are having problems where you add a bunch of pins to a map successfully, and with the same code try to add another set of pins but the app crashes, try this asap. For those who have a similar situation in this example, but haven't ran into any problems, do this anyway! Your users might add an incorrect lat/lon combo and crash the app if you give them that functionality.

Remember, (0,0) is a valid coordinate, so don't worry about this logic removing those if you are concerned about that. This is for those (-200,75) type coordinates that don't physically exist on planet Earth.