gistfile1.m

- (IBAction)showWalkingDirections:(id)sender {
    if ([self.parkingDetails.mapItem respondsToSelector:@selector(openInMapsWithLaunchOptions:)]) {
        
        NSDictionary *launchOptions = @{
            MKLaunchOptionsDirectionsModeKey : MKLaunchOptionsDirectionsModeWalking,
            MKLaunchOptionsMapTypeKey : [NSNumber numberWithInt:MKMapTypeStandard]
        };
        [self.parkingDetails.mapItem openInMapsWithLaunchOptions:launchOptions];
    } else {
        NSString *mapURL = @"http://maps.google.com/maps?";
        mapURL = [mapURL stringByAppendingFormat:@"saddr=%f,%f&", 
                  self.mapView.userLocation.location.coordinate.latitude, 
                  self.mapView.userLocation.location.coordinate.longitude];
        mapURL = [mapURL stringByAppendingFormat:@"daddr=%f,%f&",
                  self.parkingDetails.location.coordinate.latitude,
                  self.parkingDetails.location.coordinate.longitude];
        mapURL = [mapURL stringByAppendingFormat:@"dirflg=w"];
        
        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:mapURL]];
    }
}