1. Create a new Xamarin.Android application. The project template will create a single activity named Activity1 (MainActivity.cs), which contains a button.
2. From the button.Click handler in MainActivity.cs, create a geo Uri with a latitude and longitude, passing the Uri to an intent.

intent.button.Click += delegate {
       var geoUri = Android.Net.Uri.Parse ("geo:42.374260,-71.120824");
       var mapIntent = new Intent (Intent.ActionView, geoUri);
       StartActivity (mapIntent);
};

Calling StartActivity and passing it the Intent in the above code launches the maps app.

Each screen in an application is represented by an activity. Using asynchronous messages called intents, when created from a Uri, causes the system to load an activity that can handle the Uri scheme. In this recipe a Uri beginning with geo: loads an activity from the maps application at the location specified. See the Geo Uri Scheme section in the Maps and Location article for the various formats supported by this scheme.