# Walkability Compass--A Space Syntax Solution for Comparative Studies
### Explaining Walkability with Space Syntax  
#### 1.2.1 Space Syntax as Background Theory  
This research uses space syntax as a background theory and its spatial indexes to explain the walkability phenomenon, explicitly comparing studies scientifically. The term space syntax was conceived by [PERSON] and [PERSON] (1984) [12]; it uses a graph theory to analyse the spatial configurations related to how people move and adopt. The space syntax quantifies the spatial layout using topological distance approaches in network analysis. In practice, it can be applied both to street layout and enclosed within building spaces. Basically, the theory distinguishes the \"spaces\" and \"routes\" and ranks them from the most integrated to most segregated; the more integrated a space or route, the easier it is to reach. The assumption mentioned above became the basis for the Re index, also used in this research. Although space syntax uses several spatial measures, their theoretical background and calculation process has been described by, among others, (2003) and [PERSON] and [PERSON] (2002) [13; 14] and will not be described in the details here. Moreover, a comprehensive overview of evolving space syntax concepts and analytical techniques has been recently (2021) presented by [PERSON] et al. [15]. The review starts from the very beginning of the [PERSON] (1937-2019) space syntax concept, through a convex map, axial map, isovist field, to the most recent concepts such as segment map and agent-based modelling. In the context of walkability analysis, the review points out the relationship between building density and transportation as key aspects of cities' sustainability; this study follows the above interpretation (details of PoP metrics in the method section) [15]. Across the walkability interdisciplinary research methods, the time accessibility analysis [16; 17] and the graph theory can be applied; however, no study has started to apply both criteria simultaneously to assess their impact on pedestrian movement patterns [18]. The pedestrian trajectory can also be used as a related method of walking condition assessment [19]. The Space Syntax techniques are well-recognised approaches in this field. The Space Syntax interprets street network geometry using, among others, the connectivity and integration measures [12]. Street connectivity as a property of street network reflecting favourability for walking, which in three reviewed cases out of four is counted as the density of crossroads. It should be noted that the plain number of intersections addresses just the density of the street network and potential walking routes but says nothing about the character of urban spaces related to visibility, street facades. Furthermore, the number of objects could be a more precise and straightforward way to measure proximity. At the same time, the land use mix addresses it indirectly based on the premise that more land use functions create more potential travel destinations. Importantly, the residential or dwelling density identifies the concentration of walkers and the starting points of walking journeys. The connectivity and the integration as core space syntax measures [20] can contribute to walkability understanding [21]. Notwithstanding, they leave the passers-by visual contact to the urban feature unrecognised. The sole ability to quickly reach as many destinations as possible, preferably in a straight line, does not make the city walkable. The nature of the environment in which a person moves is of key importance here. The more diverse functions and the higher density of buildings within a short distance, the more walkable the space is [22]. Space Syntax, using physical features such as street networks, points of interest (POI) or buildings footprints, can also explain visual perception qualities [23]. The visual graph analysis, built on the logic of isovist analysis [24] by default applied on an at-eye level to estimate what people can see, can also be used on an at-knee level to investigate where people can move [25].