that is very true on the changing areas, a 30 year old map if you take into account any magnetic variations etc will still save your hide even more-so with an in-accurate gps (many of them out there) or 1 that is flat. A basic cheap compass will still get you out admittedly not as well as say a Silva or similar compass but enough all the same, many recorded instances where it was nothing but sheer dumb luck that people were found.