Page 81 - JCAU-7-2

Journal of Chinese
Architecture and Urbanism Spatial network analysis of hutongs

other spaces from a particular location within the system in the Qianlong Jingcheng Quantu into a network of links
(Hillier, 2008). For example, in a typical urban layout, a turn and nodes. In this abstract model, roads are represented as
represents a decision point at an intersection, while a node links, while intersections are depicted as nodes. Notably,
denotes specific places such as entrances or junctions. Within these links exclude physical attributes such as road width
this theoretical framework, accessibility is assessed based on and direction, focusing on connectivity and network
the number of turns needed to reach another space. Fewer structure.
turns indicate higher accessibility.
Observation reveals that the road network of
In a network composed of nodes and links, the depth 18 -century Beijing comprised wide, straight avenues and
th
value of a node is defined as the number of nodes that must narrow, winding, irregularly arranged alleys. The broader,
be traversed to reach other nodes in the network. A smaller straighter streets were typically named “Avenue,” “Street,”
depth value, indicating fewer nodes to be passed through, or “Small Street,” reflecting a specific street hierarchy.
suggests higher accessibility. Conversely, a larger depth value Avenues were approximately 37 m wide, while smaller
implies lower accessibility, as more nodes must be traversed. streets measured approximately 18.5 m wide (Lu & Baik ,
Numerous studies have shown that human spatial 2020). In contrast, the narrower and more irregular paths
cognitive abilities significantly decline after three directional were referred to as “Hutong.” Based on the previously
changes, a finding that shapes our methodological approach outlined characteristics, landmark roads were identified
(Guo & Wang, 2012; Lu, 2013). According to spatial syntax as those with sufficient width, high continuity, and clear
theory, the farthest distance humans can effectively perceive directionality. Therefore, this study designates the wide,
while navigating a space is known as the “three-step spatial straight streets depicted in the Qianlong Jingcheng Quantu
depth.” This theoretical framework supports the use of the as landmark roads (Table 1). Moreover, determining the
“3-step spatial depth” metric as a standard tool in research names and widths of streets distributed along the city walls
to evaluate levels of spatial accessibility. From a spatial presented challenges. However, the alignment of these
cognition perspective, the “three-step spatial depth” metric streets with the remains of the city walls provides evidence
effectively captures the limitations of human perception of their excellent transportation functionality and clear
and cognition in complex environments. It also provides directionality. Therefore, the streets distributed along the
a quantifiable measure to evaluate how environmental city walls were also included in the selection of landmark
layouts affect human navigational efficiency and spatial roads (Figure 2).
orientation. By applying this metric to the hutong area and
landmark roads, we can identify which parts of the network 4. Calculation and evaluation of spatial
facilitate easy navigation and which may pose cognitive network analysis index
challenges to pedestrians, offering insights to guide urban In a network of links and nodes, this study explores the
design improvements. relationship between the hutong system and landmark
When the spatial depth value stays within a three-step roads by measuring the spatial depth between nodes in the
range, it indicates higher accessibility. Conversely, values hutong area and those on landmark roads.
exceeding the three-step range indicate lower accessibility. To assess accessibility, this study used the “3-step spatial
Therefore, this study adopts the “three-step spatial depth” depth” as the benchmark for determining the adequacy of
metric as a measure of spatial accessibility. access within the hutong system. In addition, to evaluate
The fourth phase involves calculating the regional the overall accessibility of the hutong area, the number of
accessibility index. This step entails computing the spatial nodes that can reach landmark roads within a spatial depth
depth value for each node within the targeted area relative of three steps or fewer was counted. A higher number
to the landmark roads. The overall accessibility level of of accessible nodes indicate better accessibility within
the area is assessed by counting the number of nodes with the hutong area, while a lower count suggests poorer
a spatial depth value of < 3 steps. This analysis reveals accessibility. Based on these accessibility levels, the spatial
whether a consistent spatial organizational relationship connectivity between the hutong system and landmark
exists between the hutong area and the landmark road. roads was examined to identify inherent regularities.
3. Abstraction of the road system The evaluation involved the following steps:
and selection of landmark roads in (i) Spatial depth values between nodes were calculated
using AutoCAD software and a self-developed
18th-century Beijing application. Due to the large number of nodes, a
To effectively study Beijing’s road system in the 18 computational program was created to handle the
th
century, this research abstracts the road network depicted calculations. The process is illustrated in Figure 3.

Volume 7 Issue 2 (2025) 4 https://doi.org/10.36922/jcau.4608