Could you clarify?
What do you mean by not every room? Do some rooms not send coordinate information?
If not, for which rooms and why not?
The rooms where there is no MAP command output. The coordinates are used to draw the MAP; AFAIK there is no other use for them, and Achaean areas don't need to be Euclidian, as I can attest as I used to draw my own maps in Notepad.
Also, when you say Achaea mappers, I assume you mean the builders, not the players?
Does this mean coordinates are not guaranteed to be unique, but are likely assigned automatically? Also, do coordinates operate on a per area basis?
They're assigned manually unless I'm quite mistaken; I've pointed out some issues in the distances between rooms in a few areas which were fixed promptly. Coordinates are pretty reliably unique per area however.
Answers in bold.
I'm not sure what you mean by some areas looking bad? In the pictures above, there are no unintended overlaps or edge crossings that I see. Things are a bit crowded, but thats an artifact of drawing, rather than the layout. Also, these is an extremely good initial layout for passing into the layout program I wrote a while ago (I think you saw the link from that thread on the Achaean forums?)
Whichever Immortal does the mapmaking seems to be unable to fit everything onto one "plane", so they move sections out of the way. It usually keeps things small, but it's also annoyingly ugly from a birds-eye view. The MAP has a fixed radius, so it's okay for that, but for birds-eye maps like the ones I made and for automappers, it's just not good.
It's definitely a good place to start, though.
For a game I haven't played in years now, Achaea still presents me some interesting programming problems, heh.
Hahah, I know what you mean :D