Long ago, when energy was emanating from the Core and like mist was flowing through everything on the Cradle, there were maps on the wiki. How they were made? People could see only small part of the map and those maps also contained things not normally visible (beyond the edge).
Maps on the wiki
Yes, I meant age before that big map button. That was actually the whole point why I was mentioning mist at the very beggining. Quite late reply, yes.
To be honest, this was based on an assumption I made long ago (2011-2012), when I saw map of Gloaming Wildwoods and tried to see one distant tree on the map. As far as I remember, I couldn't see it on the map (or at least not whole), but you could see it in the distance.
Anyway, I tried to google maps of Gloaming Wildwoods and I found maps of its Shadow Lair version on some SK wiki on wikia. Then, I also found nice new versions (where accessible path is dark blue) of those original maps on russian wiki (they have bunch of nice pictures there). That brought me to conclusion, that those maps simply require a while to draw them. I don't really know what else I expected.
PS: This is quite weird, but I have just now realized what have you meant by "harvesting it from the game files". I thought you meant somehow catching map data when they are recieved by client.
I don't know. But at some point the map button in the upper-right corner of the screen was added. And that gives you a pretty big map.
If the maps you're talking about were added to the wiki before that map button, then they were probably harvested from the game files.