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Apr032011

City Beautiful

Spatial Concepts in Urban Design and GIS by KarlG 3 January 2010

Good City Form

Lynch suggested there are three historical classes of normative theories or models of city form: magical, machine and organism. Each emphasizes particular human purposes, and spatiality is fundamental throughout them all. The magical theory, which addresses needs for spiritual meaning and cosmic connection, is seen particularly in ancient Chinese and Indian design. Orientation to the cardinal directions is meaningful. Order, achieved with grids, spatial hierarchy and symmetry, is important. Gateways and approaches are imbued with magical function. The magical approach is also concerned with protection in enclosures, from the forces of chaos and more concrete enemies.

The machine model concerns parts, wholes and function. It is “still alive…in the powerful concepts of systems analysis, which models the world as a set of distinct parts linked by well-defined dynamic connections, like a giant aeroplane” (p 86). It embodies “explicit rationality,” in achieving human purposes like “equity of allocation, good access, broad choice, smooth technical function, productive efficiency, material well-being, physical health and the autonomy of parts…” (Ibid).

The city as organism is a more recent model, which Lynch associates with the “rise of biology” beginning in the 18th century. This organism has a “sharp external boundary,” with differentiated but indistinctly bounded parts. It is purposeful and dynamic, its form self-adjusting, self-repairing and self-regulating.

Lynch found many faults in these approaches to city form but reaffirms an underlying principle central to all three: that the spatial form of the city is the single most important determinant in meeting human purposes. He proposes a set of five “performance dimensions…characteristics which refer primarily to the spatial form of the city” (Ibid, p 111-118) and which correspond to five broad classes of human purpose: vitality, sense, fit, access and control. The use of the term dimension is not accidental—the degree to which purpose is afforded by a design is measurable. The desirable forms, methods and measures are spelled out at some length, and not surprisingly these are the spatial concepts found in our list.

The performance dimensions are defined briefly by Lynch as follows: vitality (“the degree to which the form…supports the vital functions, the biological requirements and capabilities of human beings…”); sense (“the degree to which the settlement can be clearly perceived…and structured in time and space by its residents…); fit (“the degree to which the form and capacity of spaces, channels and equipment…match the pattern and quantity of actions that people customarily engage in”); access (“the ability to reach other persons, activities, resources, services, information or places”); and control (“the degree to which the use and access t

City Beautiful