One point perspective has also been called central perspective and single-point perspective.In one point perspective, only one direction point is needed because the sides of all objects are moving away from us in the same one direction.This point, itself, is at times called the central vanishing point, principal vanishing point (VP) or center of vision (CV).
Horizontal Line (HL) is a horizontal line across the picture. It is always at eye level - its placement determines where we seem to be looking from - a high place, or from close to the ground.
Ground Line (GL) IS the bottom line of the picture plane of a drawing in linear perspective
Now, I'm gonna give you the example (sorry about b&w picture)
