These reporters give the maximum and minimum z-coordinates (respectively) for patches, which determines the size of the world.
Unlike in older versions of NetLogo the origin does not have to be at the center of the world. However, the minimum z-coordinate has to be less than or equal to 0 and the maximum z-coordinate has to be greater than or equal to 0.
Note: You can set the size of the world only by editing the view -- these are reporters which cannot be set.
See also max-pxcor, max-pycor, min-pxcor, min-pycor, and world-depth.
Take me to the full NetLogo Dictionary