## 2 Research Background Overview
### Research Tools  
In this section, we overview the method and the tools that were used to construct and to test IT artifacts and algorithms for the general SP and meta-pattern model. One of the most important is Space Syntax approach that is used as a computer model of space [33] and address the issues relevant to the formation of the land use strategy and location: to help boost the economy, revitalize central areas, increase social sustainability, and improve cycling and pedestrian access, as it offers an evidence-based approach and a scientific and objective tool for the decision-making and testing strategic interventions and design proposals [34]. Space Syntax is a spatial network analysis method that incorporates the urban morphology and offers the main variables of urban form (accessibility, density, diversity) and the measures of user preference and perception of open space and spatial capital [2; 7; 10]. In Space Syntax, the network made by street lines is modeled as a mathematical graph, and, from this point of view, Space Syntax approach is not unique, as a mathematical graph is used for transport flow modeling by experts of logistics [3]. The essential difference between Space Syntax and other urban modeling approaches appears in a process of graph construction: the logistic modeling chooses crossroads as graph nodes as the main points for logistics in a city [3]. Space syntax marks street axes or segments as nodes, thus focusing on spaces essential for street culture [3].  
Space Syntax can operate the axial, convex, or visibility graph analysis maps and provide a range of spatial property parameters derived from the connectivity graph (connectivity, control, integration, and many others) [2]. There are currently three methodsavailable for Space Syntax analysis: line-based (axial/segment) analysis, convex-space analysis, and grid-based analysis or VGA [9].  
VGA is a means to quantify the configuration of space as regular units which can then be used to identify the relationship of that space to the behavior of the humans that occupy it [9]. For the graph, notation is defined as \(G=(V,E)\), where \(V\) (the vertices) are the cells of the grid that are part of the graph; \(V=\{v_{1},\,v_{2},\,\ldots\,\,v_{n}\}\) and \(E\) (the edges) are the pairs of mutually visible cells; \(E=\{e_{1},\,e_{2},\,\ldots\,\,e_{n}\}\). For a specific vertex \(v_{i}\), the neighborhood (the other cells that are visible from it) is defined as: \(N(v_{i})=\{v_{j}\,|\,e_{ij}\in E\}\), where \(i\) and \(j\) correspond to the indices of the cells in the grid. An isovist is all the points visible from a specific point in space, and, in two dimensions, it can be thought of as a polygon [9]. Apart from providing a way to make the graph, isovists also allow for the creation of different metrics that described the space that is around a cell, such as its area or perimeter [9]. A more detailed overview and an explanation of main Space Syntax concepts and terms can be found in Reference [4].  
A range of software [35] has been developed to perform Space Syntax analysis, to handle geographic and geometric data associated with attribute information, to perform spatial, mathematical and statistical calculations, and to visualize the results. In this work, we use the main tool used by the Space Syntax community: DepthmapX [36]. There are 25 VGA metrics that DepthmapX can currently calculate, a mixture of classic graph-theory metrics, metrics borrowed from the urban-scale Space Syntax theories, and some VGA-specific metrics describing local spatial properties [9]. DepthmapX provides a set of global metrics, e.g., for each cell, the values are affected by every other cell in the set, and the aspect that provides this connection in VGA is Visual depth--the least amount of visual steps (a step from a cell to any other immediately visible cell) required to reach another point in the space, and, given that the grid also functions as an undirected graph, the visual metrics can be thought of as topological distance in steps [9].