Cavalary: Still also need a full size map though, accessible at all times
dtgreene: Does it really need to be accessible during combat (assuming a non-tactical turn-based combat system)?
Also, does it need to be accessible in the game over screen, or during NPC dialog, or when you're shopping or going to the inn?
Or, does it need to be accessible during load screens (if the game has them)? That might be a bit difficult from a technical perspective.
Now you're nitpicking. Typically load screens are dead times, with no user input, so that doesn't count. Same for the game over screen. Was referring to all times when you can move on it, so you'll know what's around and where to go, but it may actually be useful to be accessible during dialogs at times, now that you mention it. And that's quite an assumption about the combat system. If the encounters take place separately, in a typical JRPG style, or also in the style of TBS games generally, then accessing the map during them makes little sense, but if combat doesn't remove you from the regular environment, there may be times where you'd want to check the map while fighting, and you could have running battles too, as you advance or retreat.