paper or canvas. the image you create on that surface is drawn as if you were seeing your subject through the picture plane.
the other key concept to understand is the horizon line, which is, of course, the horizon; it is also your eye level. when you sit looking out a window at an ocean view, the horizon appears near the bottom of the window. when you stand, the horizon appears higher in the window. if you are tall enough or the window is low enough, the horizon will be above the top of the window.
imagine a plant in a flowerpot hanging outside the window. if you can see inside the 