dreammaster: I think the level 1 Wizard spell "Location" gives you the current map name, doesn't it?

narzoul: The game uses 16x16 fixed size maps, I guess you figured this out already.

Each map can be a town, a dungeon, or a section of the Outdoors area.

The Outdoors is special in that it encompasses multiple 16x16 maps, arranged into an even bigger grid of rows and columns of Outdoors maps. You can even travel between these sections by simply moving through the edge of a 16x16 Outdoors map, assuming it's not blocked by some obstacle (e.g. mountains).

The Outdoors is the only area where maps are interconnected like this. Dungeons and towns are generally completely blocked off on all 4 sides, so you can only travel between them through special passageway cells, like stairs and portals.

An Outdoors map can have multiple cells that are entry points to either a town or a dungeon. The Location spell identifies the specific Outdoors map you are on as the "map sector" using a letter and a number for columns and rows respectively (if I remember correctly).

Then, if you are inside a town or dungeon, the "surface" X/Y coordinates show the location of the entrance to that town/dungeon within the Outdoors map. The "inside" coordinate refers to your coordinates within the specific town/dungeon map. On the Outdoors, there is naturally only one set of X/Y coordinates.

A dungeon can have multiple levels. These levels are often loosely connected in the sense that if you use e.g. stairs to travel between those levels, you'll usually end up on the same inside X/Y coordinates (though there might be some exceptions to this). And all levels of the same dungeon will show the same surface coordinates.

What might be a little confusing is that multiple dungeons hosted on the same Outdoors map have no physical relationships between them at all. They're all like different pocket dimensions. So don't assume that their inside coordinates match up in any way, neither with other dungeons, nor with any Outdoors coordinates.

To sum up, you can always identify which cell of which unique 16x16 map you are on using the information in the Location spell:
- Map Sector: Identifies the specific Outdoors map you are on, or one of the dungeons whose top level entrance is located there.
- Surface: X/Y coordinates within the Outdoors map where the entrance to the town or dungeon is located.
- Inside: X/Y coordinates within the current map's 16x16 grid.
- Location: Which level of a dungeon you are in (e.g. 10' under). Towns are a bit of a special case, as they act like a "level 0" of a possibly deeper dungeon, where the first level below the town is 10' under, but otherwise they're also just underground cells within an Outdoors map.