The ones where I work are based on the distance from the north east corner of the property the building is located on, and the amount of feet from a base point set about 4 stories underground, which allows 3d mapping of the precise location of every computer in the building. IT instantly knows if a computer was moved without authorization.
Very few people even know what a computer name is, and IT was very tight lipped about what the naming convention actually stood for. It was annoying me so I took some time and figured it out. The major break was when my request for an additional computer was granted, which IT stacked on top of my other machine. Looking at the computer names, I noticed the new machine name was almost identical to my old one, except that it ended with .45 while my original ended with .0 If you assume that decimal is a base 10 representation of a foot , .45 = 5.5 inches, which was exactly how thick the computer was.
using a overhead map of the complex, I figured out where the 0,0 point was in all 3 directions. I tried out my theory on all the computers available to me on all 7 floors (5 high, 2 basement) and they were all pretty damn accurate, allowing for moving computers from one side of a cubicle to another, and my measuring error.
The really messed up thing is there are computers on the LAN with computer names, if my theory is correct, that are about 2 floors BELOW the level all the elevators go to. Spooky.