I must add that a base map is just as usefully turned off. You'll want to buy topo or road maps.
Ok, good to know! Some of the sites I've been reading seem to use 'base map' and 'road map' interchangeably. My explorist has a little bit of a map, main roads, large water bodies, but recently we were hunting in an area with a lot of small streams and little side roads. All the explorist showed was the coastline nearby, not all the smaller inlets so I ended up on the wrong side of an alligator infested creek more than once! With a better map, I would have had an easier time finding it. I don't usually complain about the challenge of the hunt, but stomping around gator, skeeter and spider infested woods with gator-nugget sized kids in tow...it left me wishing for better landmarks on my map!