Draw Road Line in Map of source to destination lat and long

 NSString *Source_latlong = @"25.4500,81.8500";

    NSString *Destination_mylatlong = @"26.9200,75.8200";

    [[UIApplication sharedApplication] openURL:

     [NSURL URLWithString:

      [NSString stringWithFormat: @"http://maps.google.com/maps?saddr=%@&daddr=%@",

      Source_latlong ,

       Destination_mylatlong]]];