Flutter – how to open another app with url but not in my app

I have an application that works according to the map, but I want another software to do the routing
I went so far that it opens the map of that navigation application, but on my own application, but I want it to open inside the same application, not on my own application.
How do I do this?

_launchURL() async {
    _getCurrentLocation().then((value) async {
      final Uri url =
          Uri.parse('https://nshn.ir?origin=${value.latitude},${value.longitude}&destination=$lat,$lon&vehicle=d');
      if (!await launchUrl(url)) {
        throw Exception('Could not launch $url');
      }
    });
  }

  Future<Position> _getCurrentLocation() async {
    bool serviceEnabled = await Geolocator.isLocationServiceEnabled();
    if (!serviceEnabled) {
      return Future.error("اجازه مکان داده نشده است");
    }

    LocationPermission permission = await Geolocator.checkPermission();
    if (permission == LocationPermission.denied) {
      permission = await Geolocator.requestPermission();
      if (permission == LocationPermission.denied) {
        return Future.error("اجازه مکان داده نمیشود");
      }
    }

    if (permission == LocationPermission.deniedForever) {
      return Future.error("اجازه مکان داه نمیشود کلا");
    }

    return await Geolocator.getCurrentPosition();
  }
}