## 2 Application of the Space Syntax Analysis to an Urban Context
### Space Syntax Analysis Theoretical Concepts  
Space syntax is a set of techniques for the analysis of urban contexts affirming that the configuration of the urban street grid generates the traffic volumes inside an urban context [17]. Space syntax has been developed by [PERSON] and [PERSON] in the early 1970s and it is a method for sociospatial analysis [18; 19]. Space syntax theory designates the urban street grid as the main generator of the traffic volumes inside itself [20]. According to space syntax theory, the traffic volumes inside an urban street grid are the sum of two components: natural and attracted movement [21]. The natural movement is the portion of the traffic volumes on each street that is determined by the configuration of the urban grid itself and not by the presence of human activities [22]. The attracted movement is determined by the presence of human activities [23]. The natural movement may not even be the dominant portion of the totality of the traffic volumes (in some cases it may be only a very small fraction), but nonetheless is recognised by the theory as the primary element generating the traffic volumes inside an urban context [24]. The human activities location inside an urban context is not a random one because each activity seeks to take advantage by streets where the benefits from the traffic volumes are the highest possible [25]. Therefore, a greater concentration of activities is expected in areas with higher traffic volumes (excluding monopolistic activities and those resulting from rigid placements) [26]. Figure 1: Flowchart showing the phases in which the research has been structured. The most used space syntax techniques are the axial analysis, the angular segment analysis and the visibility graph analysis [27; 28]. The visibility graph analysis is more suitable for building interiors because is adapted to spaces with defined areas and clear boundaries [29]. For this reason, the axial analysis and the angular segment analysis have been used in this research. The main difference between the standard urban study and space syntax approach is that the former focuses on metric distance as unit of measurement to calculate the shortest path between two points of an urban context; while the latter considers how streets visually connect with each other in a network to calculate the shortest path [30; 31; 32]. Axial analysis assumes that urban space is articulated into a plot of straight lines. Each line corresponds to a human's line of sight: by hypothesis an observer perceives the space of the city by straight lines corresponding to his perspectives and his movements in an urban context are guided by them [33]. The urban street grid can be defined as the set of all the public spaces (i.e., the spaces freely accessible to public transit). Practically, the urban grid is the set of all the streets and squares of the city [12]. Axial analysis and angular segment analysis can be performed subdividing the urban street grid in a set of convex polygons. The set of convex polygons is called convex map. The polygons are drawn in such a way to have the largest possible area and to subdivide the urban grid in the smaller possible number of polygons. Afterwards, it is possible to define the axial map that, based on the above convex map, is the minimal set of lines (axial lines) crossing and connecting every possible polygon. Axial lines are drawn as long as possible and in such a way to connect all the polygons with their fewest number. Axial lines represent the longest line of sight one has in an urban context or building and, in addition, the way humans move in lines through streets and roads or rooms and corridors [34]. The angular segment analysis is essentially an extension of the axial analysis. Indeed, in this latter case, the axial lines of the map are broken up into segments, from junction to junction. As regards the first method, each segment is weighted by the angle of its connections to other segments [35].