Get City name from Latitude and Longtiude

- (void) getAddressFromLatLon:(CLLocation *)bestLocation
{
    NSLog(@"%f %f", bestLocation.coordinate.latitude, bestLocation.coordinate.longitude);
    CLGeocoder *geocoder = [[CLGeocoder alloc] init] ;
    [geocoder reverseGeocodeLocation:bestLocation
                   completionHandler:^(NSArray *placemarks, NSError *error)
    {
        if (error){
            NSLog(@"Geocode failed with error: %@", error);
            return;
        }
        CLPlacemark *placemark = [placemarks objectAtIndex:0];
        NSLog(@"placemark.ISOcountryCode %@",placemark.ISOcountryCode);
        NSLog(@"locality %@",placemark.locality);
        NSLog(@"postalCode %@",placemark.postalCode);

    }];

}

Generate JSON string from NSDictionary

NSError *error; 
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dictionaryOrArrayToOutput 
                                                   options:NSJSONWritingPrettyPrinted // Pass 0 if you don't care about the readability of the generated string
                                                     error:&error];

if (! jsonData) {
    NSLog(@"Got an error: %@", error);
} else {
    NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}