I agree, however this and latitude longitude don't fully solve the problem the post discusses. Just because you know where the entrance is, it doesn't describe how to get there. Maybe the area isn't available on mapping services (not that uncommon for small communities, even in Western countries) or maybe you need to take a specific route to get there.
I was thinking that it would be cool to have some AR thing going (ala Pokemon Go - virtual arrow pointing toward the destination) But of course that fails if there is no direct route from where the traveler is.
To get directions working right. I think there needs to be a good open standard for road/pedestrian maps, but that will only be as good/reliable as the data source... Haven't looked into open street maps but I think that would be one to check out.
