Technically, it has all the major locations; try http://www.gamebanshee.com/arcanum/theworld.php for a thoroughly comprehensive map. But yes, it does reveal a lot that you're not supposed to know right away.

Admittedly, while I like the fact that the game uses geographical ignorance to encourage you to follow the expected plot progression while letting you explore freely if you wish (and exploit whatever knowledge you please in a subsequent playthrough), it always seemed odd to me that a character who had caught an airship from Caladon wouldn't have a clue where it was, and would be carrying a map whose creator thought bridges were more important than cities.