This is a very simple tool to determine the height of objects that are not effected by the `Map Objects To Sphere` function.
When constructing a base that covers a large area, some objects appear to float. This is due to the curvature of the planet / body your base is placed on, and that base is assumed to be constructed on a flat plane. So further from the bases 0 0 0 co-ordiates you go the grater this effect is.
This is just a ruler you can place next to the `floating` object to measure the height that the object appears to be floating, and then adjust the Y co-ordiate to make that object appears as if it is on the ground.