Perspective

"Perspective" in art is the systematic placing of visual information on a flat surface so that nearer objects appear larger than than those farther away.  Early perspective painting was concerned with depicting architectural spaces, (see Canaletto's work, above). Much later art derived from photography since the lens projects a perspective image on a flat surface.  I think Vermeer was the first to actually apply lens images in painting.  If you have any doubts, look at the recent documentary, "Tim's Vermeer". Photographic perspective varies with the focal length of the lens, the longer the focal length, the more the perspective is compressed.

Wikipedia currently states,  "Linear perspective is an approximate representation, generally on a flat surface, of an image as it is seen by the eye."  This is nonsense.  Perspective bears no resemblance to how the eye (and brain) process three dimensional visual information.

Also from Wikipedia: perspective (from Latin perspicere 'to see through').

In the early 1970's at the Art Students League I was encouraged to think of perspective by imagining a pane of glass through which to view a subject for drawing or painting, and on which to record the perspective image.  No art teacher actually tried this experiment, so I did so in my  7th Street loft. I stretched a sheet of clear plastic at arm's length and tried to draw the interior image of the loft on the plastic using a black marker. 

I was able to mark a point or two as seen through the plastic, but as soon as I focused on the plastic as opposed to looking through it, the interior image abruptly contracted because my eye refocused to arms length when viewing the marks I had drawn on the plastic.  A few more tries also revealed that I could not reproduce the light values or colors of the seen image, since the light falling on the plastic was different that that illuminating the scene.

I have since learned much more about our visual system and how different it is than the camera, but suffice it to say the concept of perspective is often antithetical to making art. An artist would do better to draw and paint the most noticeable elements in a scene, which is how the eye takes in information, rather than trying to arrange them in perspective.