The three space coordinates are named as x, y and z. The x- and y- direction are lying on the floor, the z-direction points to the top. You can let display the machine out of all three space directions, even out of several directions at the same time. Doing this the zero point is always at the bottom left. Experienced computer user have to get used to it because normally the zero point of the screen is at the top left. An upholding of this convention would have caused that the z-values increase from the top to the bottom and you would have to get used to it as well.
The unit of measurement in that the position of the elements is specified you can select between 0.1 mm, mm, cm, and m. Normally mm are specified.
The positions of the elements are always specified corresponding to the zero point.
See also: