I wonder how many of these people regularly visit other countries as tourists.

No they are (were) an actual native Android apps that install automatically without needing to go through Google play. They have a much tighter sandbox and restricted access to system APIs as a safety measure.

Simple, add additional columns for the frame of reference (e.g. Earth) and elevation. You could even store space coordinates using Sun as a reference point (though you would need to update data regularly for spacecraft as they move of course).

Why do you need to store the name of a country in the database? Frontend can take the country code and display a full name on its own, and do it in a localized way too.