Formal, syntactical and subjective dimensions of spatial legibility in configurationally differentiated patterns

Legibility is described as the possibility of organizing an environment into an imageable and coherent pattern. There are many concepts in the literature that define legible environments: simple, coherent, understandable, perceivable, imageable, etc. All these concepts point to the characteristics deriving from the structure of space. In order to measure spatial legibility through these concepts, a distinction should be made within the dimensions of space.There is a relationship among the methods used in spatial knowledge acquisition, the elements of spatial knowledge, and spatial legibility, as the elements of spatial knowledge refer to the features that provide a space to be legible. On the other hand, spatial knowledge acquisition is related to subjects? cognitive processes. Hence, there is a relationship formed by various combinations of spatial knowledge acquisition, cognitive processes, and spatial legibility. The three elements of spatial knowledge -survey knowledge, route knowledge and landmark knowledge- are defined by the researchers in the related literature several times. Experiments are conducted to measure survey, route, and landmark knowledge. Various dimensions of spatial knowledge have been tried to measure in these experiments through tasks. The strategies used in these tasks vary from one subject to another because of the highly subjective cognitive processes in this step. Survey knowledge, route knowledge and landmark knowledge, on the other hand, are connected to the legibility of space. The landmarks, being salient and differentiated elements of spatial system, ease the readability of space. Whereas landmark knowledge emphasizes three dimensional aspects of space, the knowledge of route and survey forms, through the complexity or simplicity of spatial configuration, a connection between two-dimensional knowledge of space and spatial legibility. Some researchers claim that as people get familiar with space, they conceive landmarks, routes and configuration (survey) respectively. This study aims to discuss the three related concepts (spatial knowledge acquisition, cognitive processes and spatial legibility) and to reveal the points that three concepts intersect.A pattern of spatial layout (or survey knowledge), thus, may contain landmarks in addition to a street network or urban blocks. Yet the basic characteristic is the street network or urban blocks. Two kinds of pattern can be noted: 1. the ideal or orthogonal grid and 2. the organic or deformed grid. The differentiation of a pattern in terms of uniformity / diversity is based on the grid type. Similarly, homogeneity / heterogeneity degree of a spatial pattern is affected by grid type as well. Ideal grid, for instance, can form the highest level of uniformity and homogeneity. On the other hand, inclusion of landmarks to the system can dramatically change the situation. Uniformity / diversity and homogeneity / heterogeneity degrees are directly related to the legibility of a pattern. If the layout is read from a map, adding texts that point to the streets or landmarks of a pattern is another factor that would affect the legibility of the pattern. All these added features like landmarks, texts or colour will provide or enhance hierarchy in the pattern.This study uses three different methodologies to examine legibility in differently configured patterns (varying from ideal grid to organic grid): formal analysis, syntactical analysis, and subjective analysis (experimental case study). Thus, spatial legibility of urban patterns is evaluated through subjective (experiment) and objective measures (formal and syntactical analyses). The results of the study determine a new definition for spatial legibility and present a discussion for ontologically different dimensions and ways to study legibility.