Have you ever been playing Phantasy Star IV, and gotten lost in the overworld map? Ever wonder exactly where Esper Mansion was, or if Dezoris' overworld map wraps around like Motavia's? Did you wish Sega had included maps of the planets, like Phantasy Star III's Monitor?
What's that you say? They didn't? Afraid they did. Two planet maps, one for Motavia and one for Dezoris, are coded into the game, and can be viewed using an edited saved game. Sega simply chose to not allow players to have access to the maps. Why? Two valid theories have been suggested.
First, including the maps might have made the game too easy. This is certainly possible - it's fairly easy to find most places in the game already, so being told where to go wouldn't do much for the difficulty. The second theory is that the maps didn't work correctly. To see why I think that is a possibility, you need to see the Dezoris map. So, here it is:
Notice the parts at the top and bottom of the map that appear to have something like static. It's my opinion that this map caused some sort of problem in the game, and this resulted in scrapping the entire idea of in-game maps for Phantasy Star IV. Why do I think this map caused the problems? Two reasons: first, there's no Rykros map in the game. Second, the Motavia map looks fine:
I do believe that these maps were intended to be included in the game. Evidence of this can be found by using the "Look" function of the item menu to examine the map item. (The map is called NOTHING in the item list, and cannot be sold at a shop.)
Why would the item have a description, if it were not intended to be in the game? It should also be noted that there is only one map item. The map shows either Motavia or Dezoris, depending on which planet you are on.
For those wanting to compare these maps to the games, structures are indicated in white on the Motavia map, and brown on the Dezoris map (Esper Mansion isn't shown). The Dezoris map also offers proof that the overworld map of Dezoris does wrap around the planet. The large, dark areas in the center of the Dezoris map are Crevice and Skure, each of which appear to contain bridges or other landforms on the map. No such bridges are there in the game, of course.