-- Matt Frost (email)

How could it be any other way?

Dimensionality reduction is often observed in Nature. People see the equivalent of plan-views all the time: from the top of the mountain, shadows projected on the ground, even contour lines (tidelines on the beach) on a sloping flatland, the shape of the sun in the sky, a cut through a treetrunk, a curled leaf flattened under a rock, the horizon at sunset looking at a range of mountains. In Nature, there are probably many flatland projections of spaceland realities.

In the French cave drawings 15,000 to 25,000 years ago or so, animals (spaceland objects) were depicted on the wall's 2-surface. Plan-view and elevation-view are analytically equivalent for our purposes here. By the way, Arnheim once suggested that the 2-D animal-outlines drawn on cave-walls developed from the glowing edge you see outlining an animal (a dog for example) through its fur when the animal is between you and a low sun in the background. (Recent reports claim that domesticated dogs were around 150,000 years ago, long before the French cave paintings at least.) Or possibly a pointed drawing instrument might encourage outline drawings since it difficult to construct a continuous surface texture with a pointed stick or sharp rock. A paintbrush would do better.

In Visual Explantions, chapter 1, I argue the great big intellectual step with regard to maps was changing the names of the coordinate system from north-south and east-west to X and Y, that is, to any sort of empirically measured quantities for plotted observations. It was that abstraction of the map, only 500 years ago or so, that made statistical graphics possible.

Perhaps there are planview genes just as there are language genes.

Quite a number of people have a hard time reading an architectural plan-view and especially an elevation cut (as architects discover when presenting a project to a client). Experience is a fairly rapid teacher, however.

-- Edward Tufte