Equivlent Objective-C code for Google Maps GMap2.getBoundsZoomLevel(bounds)?

Question

Hi all,

I'm familiar with the Google Maps API and I'm trying to learned the iOS MapKit library now. I have an iPhone application which takes an input string and geocodes it using Google Maps geocoder service. I also want to set an appropriate zoom level for the new map but I'm not quite sure how to do it.

After reading, http://stackoverflow.com/questions/312517/determining-zoom-level-from-single-latlong-in-google-maps-api#917997

My plan was to parse the JSON response from the Google Maps API and extract the ExtendedData field.

 "ExtendedData":{
     "LatLonBox":{
         "north":34.13919,
         "south":34.067018, 
         "east":-118.38971, 
         "west":-118.442796
     }

Then using that I would like to set the bounds of my map accordingly using the MapKit setRegion function.

I started laying out a function to do this, but I'm a little lost on the logic...

- (void) setMapZoomForLocation(CLLocationCoordinate2D location, double north, double south, double east, double west){

    // some fancy math here....

    // set map region
    MKCoordinateRegion region;
    region.center = location;
    MKCoordinateSpan span;

    // set the span so that the map bounds are correct
    span.latitudeDelta = ???;
    span.longitudeDelta = ???;

    region.span = span;
    [self.mapView setRegion:region animated:YES];
}

Alternatively, I guess I could just used the Accuracy result from a geocode result to set a sort of default zoom level. I'm just not sure how to compute the equivalent default zoom levels for the various results.

See https://code.google.com/apis/maps/documentation/geocoding/v2/#GeocodingAccuracy