linear perspective basics

Two drawings are needed to construct a perspective drawing. A third is often necessary, but can be embedded in the second. The first is a map that gives scalable, 2-dimensional information about the orientation of viewer-to-object. I call this the Setup. It's often a plan that includes the viewer's location (SP). What's missing is vertical measure: eye height above ground of the viewer and the height/elevation of the object. (that missing elevation is very often the useful third document) Kevin Forseth's book has very clear illustrations. Here is an example of a Setup from his book:
station point (SP): the putative position of the viewer

line of sight (LOS): a straight line, often parallel to the ground, from the eye of the observer to the center of a scene

cone of vision (COV, FOV) : a peripheral limitation to the field of view -- a cone whose apex is at the station point and whose angle is between 35ºmin-60ºmax

picture plane (PP): an imaginary plane, perpendicular to the line of sight, from which the scaled measure of objects may be taken. In a one-point perspective, the picture plane can be coplanar with an elevation or section.

horizon line (HL): appears to cross through anything standing at the same height above ground as the eye level of the viewer; once it has been assigned a numerical value, the height of volumes on the ground can be inferred. Its usefulness is broad but still limited, and works most predictably when the line of sight is perfectly horizontal and parallel to the ground.

center of vision/central vanishing point (CVP): The geometric center of a perspective construction. The point where the line of sight intersects the picture plane, and the vanishing point for any lines oriented perpendicular to the picture plane. A perspective composition can be cropped such that the center of the construction is no longer located in the center of the frame.