// HASKELL MODULE HIERARCHY, BY DON STEWART
A previous entry focused on Kevin Lynch’s The Image of the City to explain why a waterfront is significant in structuring city image through formal legibility. Those concepts will be referred to here in an attempt to explain how image is constructed from a formal standpoint (as compared to social or economic). For more explanation, see: The Image of the City.
DIRECTING THE IMAGE WITH SYMBOLIC DEVICES
Although it plays a significant part, the creation of city’s image is not limited to its physical form or its cultural context. If a user creates his or her mental model of a city based on a networking of symbols (paths, edges, districts, etc.) then it follows that the choreographing of these symbols would have a major effect on how one structures their notion of a city. If explicitly told what the symbols are and how they relate, you can shortcut the process of legibility because the image is being constructed for you.
How can these symbols be choreographed if each user’s experience of the city is personal and unique? The simple device of a map does just that. Whether you look at a map before or after you experience a physical environment, the elements are laid out in front of you, in perfect clarity. If legibility is the route to image cohesion, then a map is the cheat sheet.
// MAP OF MANHATTAN'S DISTRICTS
GEOGRAPHY VERSUS TOPOLOGY
An important aspect in mapping is giving careful consideration to the difference between geography and topology. Geographic information defines measurable things such as physical distance or geometry. Topology, on the other hand, defines the set of internal relationships between elements.
// A GEOGRAPHIC MAPPING OF LONDON'S TUBE (ADHERES TO PHYSICAL LOCATION)
// A TOPOLOGICAL MAPPING OF LONDON'S TUBE (ABSTRACTION TRADED FOR CLARITY)
One of the most interesting aspects of Lynch’s argument is that the focus nearly always rests in topology, not geography. In other words, the relationship between the parts is of far more importance than their physical orientation or distances. This focus is exemplified when Lynch writes of right angles in city planning. He argues that the perception of two streets meeting at a right angle is more important than the reality of a ninety-degree angle. Furthermore, the mistaken perception of a right angle is highly problematic as it inevitably leads to confusion when a network of streets does not link up the way that a user would naturally assume. The assumptions about the environment were mistaken and the ensuing mental model led the user astray. A reliance on a presumed geographic relationship led to an incorrect topological model. Lynch would argue that this is a case of poor planning, where legibility was not adequately considered.
Unsurprisingly, Lynch’s five structural components found in cities rely on topological relationships. Paths, edges, boundaries, and districts define specific relationships, but speak nothing of specific geometries. Geometry is left undefined and open-ended. A path might be perfectly straight or it might wind haphazardly. What is important is that it connects point A to point B. The same is true of an edge. It is recognizable as an edge along its entire distance, whether it strikes a meandering trajectory or not is another story. A district too has geographic plasticity. It might be rectangular or it might be a crescent in plan. However, it’s understood in a topological sense, where one can recognize whether something is or is not contained within the district. Lynch, therefore, is indirectly arguing that studying the topological composition of a city will lead to a deeper understanding of its image.
INCLUSION, OMISSION, AND RELATION
A tourist map is often constructed with close attention paid to relationships, but not to distance or geometry. This is the perfect example of favoring topology over geography. The mapmaker is not interested in conveying to the reader an accurate portrayal of the streets and districts that they will encounter. Only the essential information is included to structure a core understanding of the city through as basic a mental model as possible. After all, the user will only need to retain this model for a short time. It needs to be just enough to navigate the city, but not so much that the structure is confused and muddled.
To a short-term visitor, accurate distances, shapes, and angles are not important if they cloud the necessary skeletal relationships that make the city legible. If monument X is down the road and to the left from monument Y, the tourist needs to know that. He or she does not necessarily need to know whether it’s a quarter mile or a third of a mile, or if the road gently bends to the east. For the tourist, the topological relationship is required, the geographical one is extraneous. This is similar to Lynch’s right angle problem, where topology is incorrectly derived through false geographic assumptions. Thus, in the case of a bare bones mental model, topology bears more weight than geography. The qualities of relation are the building blocks of city image at a very basic level (a waterfront, as previously discussed, often being the dominant player).
// TOURIST MAP OF VENICE
MAP TYPOLOGIES
A map must bias information in order to simplify and clarify it. The inclusion of (or erasure of) information is what makes the map useful. It is a symbolic device, meant to help you structure the complexity of an environment in a meaningful way. The larger the audience that the map reaches, the stronger its particular organization of symbols is engrained in the collective memory of the public. A map, therefore, takes on the role of consensus-maker.
While topological relationships generate the base of its structure, much more can be inferred about city image if one looks specifically at the type of structural elements that dominate in a particular city. Putting aside the specifics of its content, a map’s presentation of information is always biased simply through the ‘type’ of information that it chooses to present. The type of information relayed in the map not only says a lot about the city it represents, but a lot about the way that the reader will construct their image of the city. This is true of experience (a visitor that rides a tour bus will see a series of disconnected monuments, scattered in a soup of urban infill, while a taxi driver might see their city as a dense network of paths), but it is also true of maps. Identifying the typology of mapping elements can shed light on the structural strategy of a city. Does the map focus on monuments? Or is it a network of paths? Or a hard-lined grouping of districts?
// PARIS DESCRIBED AS MONUMENTS
// PARIS DESCRIBED AS DISTRICTS
If a city is thought of in terms of path, it will be interpreted one way. If districts are the dominant element, then it will be considered through a different lens. All cities are composed of a mix of structural element types, but if one or two of them carry the weight then image legibility will rely disproportionately on them. Some cities are certainly seen as a collection of strongly defined districts (Boston). Others are known for their dominant and hierarchical paths (Paris). These characteristics are often reflected in both their typical maps, but also their respective urban images.
// BOSTON'S DISTRICTS
// PARIS' PATHS
INTERVENTION
If maps are reflective of image consensus (or, alternatively, affecting the consensus themselves) then they are a formal manifestation of city image. Maps can serve as a guide or diagram to the existing fabric of imageability and inform a designer how to read that image. A ‘district’ city, for example, must be operated on in terms of its districts. The vocabulary of design must be applicable to the district. Otherwise, imageability will suffer. As the backbone to strong legibility, the urban waterfront should play this game as well. An element at the scale of a waterfront must confront its city in the terms that reflect its perceptual armature. If the city is primarily made legible by its strong paths, then its waterfront can use path as a mode of operation and jumping off point for the vocabulary of its conceptual framework.
Ultimately, image is a product of emotional response, but it has its roots in the formal structure of a perceived object (or city). By identifying the typology of the dominant structural components, a designer can operate within the perceptual landscape of a city effectively. Thus, design intervention in that landscape (on its own terms) can gel with the urban image more seamlessly.
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