Indeed, a distinctive and legible environment not only offers security but
also heightens the potential depth and intensity of human experience.
Although life is far from impossible in the visual chaos of the modern
city, the same daily action could take on new meaning if carried out in a
more vivid setting. Potentially, the city is in itself the powerful symbol
of a complex society. If visually well set forth, it can also have strong
expressive meaning.
...
If an image is to have value for orientation in the living space, it must
have several qualities. It must be sufficient, true in a pragmatic sense,
allowing the individual to operate within his environment to the extent
desired. The map, whether exact or not, must be good enough to get one
home. It must be sufficiently clear and well integrated to be economical
of mental effort: the map must be readable. It should be safe, with a
surplus of clues so that alternative actions are possible and the risk
of failures is not too high... The image should preferably be open-ended,
adaptable to change, allowing the individual to continue to investigate
and organize reality: there should be blank spaces where he can extend the
drawing for himself. Finally, it should in some measure be communicable
to other individuals. The relative importance of these criteria for a
"good" image will vary with different persons in different situations;
one will prize an economical and sufficient system, another an open-ended
and communicable one.
...
...This leads to the definition of what might be called imageability:
that quality in a physical object which gives it a high probability of
evoking a strong image in any given observer. It is that shape, color, or
arrangement which facilitates the making of vividly identified, powerfully
structured, highly useful mental images of the environment. It might also
be called legibility, or perhaps visibility in a heightened
sense, where objects are not only able to be seen, but are presented
sharply and intensely to the senses.
...
A highly imageable (apparent, legible, or visible) city in this peculiar sense would seem well formed, distinct, remarkable; it would invite the eye and the ear to greater attention and participation. The sensuous grasp upon such surroundings would not merely be simplified, but also extended and deepened. Such a city would be one that could be apprehended over time as a pattern of high continuity with many distinctive parts clearly interconnected. The perceptive and familiar observer could absorb new sensuous impacts without disruption of his basic image, and each new impact would touch upon many previous elements. He would be well oriented, and he could move easily. He would be highly aware of his environment.