# Walkability Compass--A Space Syntax Solution for Comparative Studies
## 2 Method
### The Research Method
#### 2.2.2 Space Syntax Calculations Method (Steps 4-6)  
Next, the graph analysis of the street network as a pre-validation of the graph model was performed in the 4 th step (validated in step 5). In total, the seven following Space Syntax metrics, including angular segment measures [55] and metric segment measures [23], were calculated using different analysis radius size parameters:  
1. Angular segment choice or betweenness centrality, which identifies the probable axes of transit within various radiuses and is calculated as a sum of simulated journeys according to the shortest paths between nodes;
2. Angular segment integration or closeness centrality, which identifies the possible zones of attraction or urban centres within various radiuses; it is calculated as reciprocal to a sum of distances between the nodes multiplied by a segment number in Space Syntax Segment analysis;
3. Metric segment choice within a radius of 1000 m differs from angular segment choice in how the shortest path is found: it is based on measured distances instead of a sum of angles of the turns on the path. According to [PERSON] [56], metric distances reflect pedestrian behaviour better in some cases;
4. Metric reach within the radius of 1000 m as the length of the reachable street network;
5. The total metric depth of 1000 as a sum of distances between nodes while distance is calculated in meters;
6. Node count as several nodes/street segments within selected radiuses;
7. Angular segment total depth as a sum of distances between nodes while distance is calculated in angles of turns. Step 4 was executed using open-source DepthMapX (v. 0.8) software (Space Syntax Limited, London, UK) [57]. The calculation results exported as a text file to SPSS software were the subject of the correlation analysis aimed to validate the model. The validation performed in the 5 th step allowed us to assess whether the Space Syntax model works properly and reflects regularities of the fundamental urban functions. The obtained measures are not random and reflect the urban structure recorded in the spatial data. Any potential lack of correlation indicates topological errors or lacks in the source data. The models were validated by comparing the segment graph models of the street networks of all the investigated cities with the allocation of POI and public transport stops. The idea of comparison is based on [PERSON]'s concept of movement economy [56]. The 5 th step procedure includes Pearson and Spearman correlations between the space syntax metrics obtained in the 4 th step and density of POI, including bus stops as indicators of real urban centralities. Calculations were made using SPSS Statistic software (v. 26) [58]. In practice, two layers of data (space syntax indicators and POI) were spatially joined within 200 m. The distance of 200 m was chosen as the smallest meaningful urban resolution grid size according to [59], which reflects the physical size of POI and the closest catchment area of bus stops. The correlation results were presented in Section 3.1 within a table format highlighting values higher or equal to 0.5, which were regarded as strong and significant to validate the network space syntax model used as a background for a more expanded walkability model. The next stage ensures that the model works correctly and calculates the key walkability metrics. As the model was validated against POI, the explanatory walkability metrics were calculated as the main task of method workflow 6 th step. At this stage, the analysis environment of the building's centroids was added to the analysis, and all the calculations were made using Urban Network Analysis Toolbox [60]--an ArcGIS software plugin. The tool input parameters specify the calculation radius. At this point, we applied the 15 min city concept [45], approximating that a 1 km distance can be beaten at such a time. The Urban Network Analysis toolbox can compute five different types of centrality metrics on spatial networks of buildings--Gravity Index, Reach, Betweenness, Closeness, and Straightness.