2003-12-03 The Image of the City- typology of image elements p47 """ The contents of city images so far studied, which are referable to physical forms, can conveniently be classified into five type of elements: paths, edges, districts, nodes, and landmarks. Indeed, these elements may be of more general application, since they seem to reappear in many types of environmental images, as may be seen by reference to Appendix A. These elements may be defined as follows: 1. Paths. Paths are the channels along which the observer customarily, occasionally, or potentially moves. They may be streets, walkways, transit lines, canals, railroads. For many people, these are the predominant elements in their image. People observer the city while moving through it, and along these paths the other environmental images are arranged and related. 2. Edges. Edges are the linear elements not used or considered as paths by the observer. They are the boundaries between two phases, linear breaks in continuity: shores, railroad cuts, edges of development, walls. They are lateral references rather than coordinate axes. Such edges may be barries, more or less penetrable, which close one region off from another; or they may be seams, lines along which two regions are related and joined together. These edge elements, although probably not as dominant as paths, are for many people important organizing features, particularly in the role of holding together generalized areas, as in the outline of a city by water or wall. 3. Districts. Districts are the medium-to-large sections of the city, conceived of as having two-dimensional extent, which the observer mentally enters "inside of," and which are recognizable as having some common, identifying character. Alwats identifiable from the inside, they are also used for exterior reference if visible from the outside. Most people structure their city to some extent in this way, with individual differences as to whether paths or districts are the dominant elements. It seems to depend not only upon the individual but also upon the given city. 4. Nodes. Nodes are points, the strategic spots in a city into which an observer can enter, and which are the intensive foci to and from which he is traveling. They may be primarily junctions, places of a break in transportation, a crossing or convergence of paths, moments of shift from one structure to another. Or the nodes may be simply concentrations, which gain their importance from being the condensation of some use or physical character, as a street-corner hangout or an enclosed square. Some of these concentration nodes are the focus and epitome of a district, over which their influence radiates and of which they stand out as a symbol. They may be called cores. Many nodes, of course, partake of the nature of both junctions and concentrations. The concept of node is related to the concept of path, since junctions are typically the convergence of paths, events on the journey. It is similarly related to the concept of district, since cores are typically the intensive foci of districts, their polarizing center. In any event, some nodal points are to be found in almost every image, and in certain cases they may be the dominant feature. 5. Landmarks. Landmarks are another type of point-reference, but in this case the observer does not enter within them, they are external. They are usually a rather simply defined physical object: building, sign, store, or mountain. Their use involves the singling out of one element from a host of possibilities. Some landmarks are distant ones, typically seen from many angles and distances, over the tops of smaller elements, and used as radial references. They may be within the city or at such a distance that for all practical purposes they symbolize a constant direction. Such are isolated towers, golden domes, great hills. Even a mobile point, like the sun, whose motion is sufficiently slow and regular, may be employed. Other landmarks are primarily local, being visibile only in restricted localities and from certain approaches. They are the innumerable signs, store fronts, trees, doorknobs, and other urban detail, which fill in the image of most observers. They are frequently used clues of identity and even of structure, and seem to be increasingly relied upon as a journey becomes more and more familiar. """ These five would be useful in any context of dividing up space. What's maybe interesting is that I seem to remember the brain uses landmarks itself -- I read an article that said when somebody describes a route to something, the bits of their brain that are stimulated when *at* certain landmarks light up as they *describe* those landmarks. The route is a set of symbols, in other words, abstracted from the experience itself. What if what Lynch is describing a is a kind of understood folk wayfinding (cf Dennett's folk psychology), that these elements really do map almost-or-approximately to hardwired symbol types in the brain? If that's the case then understand how they relate and the properties of each would be really important. In cyberspace, it's nothing but nodes and paths. But there's no concept of locality, of accidental distance, so there's edges round everything: you can't see from node to node unless somebody's already made a path. Districts have to be deliberate too (although I guess it can occur accidently, or in an emergent sense too: the similar design of blogspot sites; the sprinkling of "Powered by Blogger" slogans across the www). That's a case of infoscent: at each node, the subtle trace of every other node. But landmarks are pretty much impossible. (It would make a good short story, I think: Consider three nodes joined by paths, drawn on the page. Actually this network defines a space, not the space when it's drawn, but the paths and the node *is all there is* (like the expansion of space-time doesn't expand *into* anything, it creates space as it goes). But lets be a little silly and pretend that the triangle, the brane created as a surface described by these arcs is really a space is some other dimension. What would it look like to view the www from this new viewpoint? Could it be simulated on the www itself? How about at higher dimensions? Of course, as soon as you make a page to be this surface, it's no longer a surface: it's another node. So you couldn't do it with browsers, or with any system that has a discrete location.) Mapping to other terminology I've used: I've also talked about rooms and corridors before. Rooms are nodes with no intrinsic distance; if you speak in a room it's available to all other points in that room. These are nodes. Corridors don't really exist online because they have intrinsic distance: you can exist at different points in the corridor, and transformations attenuate along the length. These are trails (in Memex) or dimensions (in ZigZag); they're absent from the WorldWideWeb version of hypertext. I've also, when talking about distance, talked about negative distance (statement-wormholes, cybernetic feedback loops) -- these correspond to paths: paths are a bit too conduit metaphor, a bit "the channel is independent from the information", and I'd prefer to think of condensations of conducting space instead (space over which it's easier to move, where time is less dense), but it'll do. I've also talked about positive distance, which is distance which doesn't have to declare its endpoints: it affects nodes around it by virtue of existing inside another space. Positive distance is created by walls, where nodes on either side get further apart. It's not really possible to do this online without controlling the endpoints and breaking the wormholes (links) -- the closest simulation is just deleting a page (and therefore creating broken links all over the place): walls are magical; they're action-at-a-distance. Positive distance is edges. With a lot of edges you can create a maze; a maze is the opposite of a black hole.