Check out my personal thread for more info, I did write a bit about it. Point 0,0,0 is the exact central voxel of where you clicked the the map when disembarking, the exact center of your map. 0,1,0 is 1 voxel above the center. 0,-1,0 is 1 voxel below the center, and possibly, depending on the map and generation type, below the ground. If you use Microworld, then -1 on the Y axis corresponds to 1 block below the ground.
e: Allow me to link you some resources that I know and have used around this site. Reading through them should give you a very broad overview of some of the game’s systems.
Stonehearth official modding guide
In-depth look at AI
RepeatFeed
And you are familiar with my thread.
e2: Now that I’ve re-read it, my thread is pretty barren when it comes to usable content. :\ I’ll need to post more often to that.