Table 1 The main indicators in spatial syntax

Depth value

\(MD_{i} = \sum\limits_{{j = 1,j \ne i}}^{n} {d_{{ij}} /\left( {n - 1} \right)}\)

Depth value D_i is the shortest topological distance between a certain space and all other spaces. The Mean depth value (MD_i) represents the average of the sum of topological distances between a certain space i and all the other spaces. d_ij represents the topological cost (step size) experienced from node space i to node space j

The greater the depth value, the farther the topological distance, and the more isolated the space is

RRA value

\({RA}_{i}=2\left({MD}_{i}-1\right)/(n-2)\)

\({D}_{n}=2\left\{n\left[{{\text{log}}}_{2}\left(\left(n+2\right)/3\right)-1\right]\right\}/(n-1)(n-2)\)

\({RRA}_{i}={RA}_{i}/{D}_{n}\)

\({I}_{i}=1/{RRA}_{i}\)

RA_i is the result of a one-time normalization of MD_i in order to normalize the parameters distribution. RRA_i is the result of the second normalization of RA_i using D_n as the normalized parameter. I_i denotes the integration degree of a space i

RRA and I are used to express the accessibility of a space as a destination. The higher the integration degree I, the higher the accessibility of the space, reflecting the centrality of the space in the entire residential space. In this paper, the reciprocal of I, the RRA value, is used to measure the degree of integration, that is, the higher the RAA value, the lower the integration degree

Control value

\(Ctr{l_i} = \sum\limits_{j = 1}^k {\frac{1}{{{C_j}}}}\)

j (j = 1,2,3…, k) is the space directly connected to space i, k is the total number of these spaces, and C_j is the total number of spaces directly connected to space j

The Control value Indicates the degree to which a space has control over the space directly connected to it, with higher values indicating greater influence on the surrounding space