Analysing the Concept of Legibility
Authors: Emine Koseoglu, Deniz Erinsel Onder
YAPI, June 2010, Issue 343, pp.52-56.
When the concept of spatial legibility is defined as an observation, seeing, understanding, analysis or evaluation, it becomes possible to speak of as many readings or methods as there are dimensions or directions in the space or urban space. Yet spatial legibility differs from the concept of reading. The concept of legibility occurs as one of the principles of urban design in literature on the subject.
Many researchers give a definition of legibility, and the principle source they cite is Kevin Lynch, who defines legibility as follows: "Legibility means the possibility of organising an environment within a noticeable and consistent texture." According to Lynch, the easier it is to form a mental image of an environment, the easier it is to read. Other researchers have defined ¬legibility as a concept that provides a meaning which helps to create and give direction to a mental map, and points to the characteristics of a large-scale environment. Reading an environment is a process that evolves with the obtaining of spatial information from the environment concerned, and by mentally processing that information using it in a way appropriate to its purpose. Two components play a part in the process of obtaining spatial information: the characteristics of the space and the characteristics of the observer. The observer's perception and understanding of the characteristics of a space occurs as a result of spatial-psychological processes that happen in the mind. These processes are influenced by the personal characteristics of the observer. At the same time legibility is influenced by spatial characteristics. Whether a space is legible depends on the plan layout in the second dimension and its complexity, and whether the architectural components in the third dimension are discernible.
Literature on the subject contains many concepts that define legible environments: simple, consistent, understandable, perceivable, organisable, etc. All these concepts point to characteristics deriving from the structure of the space. However, it is impossible to measure legibility by these concepts. For this reason the model discussed in this article uses two variables to devise a definition based on characteristics deriving from space: 1. the complexity of spatial layout and 2. the definability of sign elements. The complexity of spatial layout describes the two-dimensional information about a space, while the definability of sign elements describes the three-dimensional information about a space. These two variables are also the elements of spatial information used while finding direction.