# Analysis of Development Coordination Levels between Skywalk Systems and Urban Spatial Environments
## 2 Literature
### Elements of Skywalk System Indicators
#### 2.1.2 Evaluation Factors  
Factor parsing was performed based on the five dimensions selected above: scale, connection strength, spatial structure, vertical transportation locations, and closure attributes.  
Scale includes three evaluation factors: length, width, and number of connected blocks. A longer length indicates a more extensive skywalk system, facilitating greater connectivity between more buildings and functional areas [36]. The width of a skywalk reflects its capacity and comfort, with wider skywalks accommodating more people and activities [37]. A greater number of connected blocks indicates more connectivity and diversity, thus meeting the characteristics and needs of different neighborhoods while facilitating interactions between them [6].  
Connection strength is categorized in terms of plan and profile. Plan connection strength is subdivided into four evaluation factors: connecting only, through the building, attached, and nodal. Skywalks connecting buildings only provide the shortest path of passage between two buildings, while skywalks through buildings integrate with architectural spaces. Skywalks attaching buildings combine the characteristics of the above two categories, and skywalks forming nodes can expand the walking space and the range of activities [38]. The strength of profile connections is divided into two categories: low area connections and high area connections [12]. Low area connections provide walking paths between businesses on the ground floor of the building, and high area connections allow for quick access between high-rise offices and rooftop terraces.  
The spatial structure is divided into three categories: linear, nodal, and network. Linear structures are more commonly situated along the main access routes and can connect the main nodes through the shortest paths. Nodal structures enhance the radiation and convenience of the skywalk system in the core area. Network structures provide multiple paths, increasing the flexibility of the skywalk system [20].  
Vertical transportation locations are divided into two categories: inside the building and outside the building [5]. Vertical transportation set inside the building can utilize the building's infrastructure, saving pedestrians space and time by providing easy access to building elevators while protecting pedestrians from inclement weather. Vertical transportation set outside the building is not affected by the building operation hours, allowing for 24-h public access and better integration into the three-dimensional transportation system.  
Figure 1: Indicator elements of a skywalk system.  
Closure attributes are divided into three categories: closed, roofless and windowless, and covered and windowless. Closed skywalks protect pedestrians from external environmental factors such as rain, snow, cold, and heat [39]. Covered, windowless skywalks provide a more open, natural environment that allows pedestrians to walk while enjoying the surrounding landscape. Covered and windowless skywalks blur the boundary between buildings and public spaces, facilitating transitions and enhancing connectivity between buildings and public spaces [40].