# Analysis of Development Coordination Levels between Skywalk Systems and Urban Spatial Environments
## 2 Literature
### Elements of Urban Environment Indicators
#### 2.2.2 Evaluation Factors  
Factor analysis is based on the three dimensions mentioned above, namely the natural environment, social and economic environment, and urban built environment.  
The natural environment includes four factors: number of days with extreme temperatures, average annual temperature, average annual rainfall, and average annual snowfall. The number of days with extreme temperatures reflects climatic extremes, with a greater number indicating a higher need for a skywalk system to provide a comfortable walking environment [42]. The average annual temperature reflects the heat profile of the climate and can influence the choice of form in which the skywalk is constructed [43]. Average annual rainfall reflects the climate's wetness, with walkways providing rain shelter, while average annual snowfall reflects its coldness, with walkways providing shelter from wind and snow [44].  
In previous studies, the social and economic environment would be measured using five factors: total crime index, level of bachelor's degree education, average annual household income, white-collar employment rate, and regional population; in addition, they would also have an impact on the construction of the skywalk. It has been shown that population size affects the size, location, and type of skywalk systems [45]. A lower crime index suggests a less safe city, leading pedestrians to prefer closed, separate, off-the-ground walking systems [46]. A higher level of bachelor's degree education increases the need  
Figure 2: Indicator elements of urban environment.  
for skywalk construction [47]. Similarly, higher average annual household incomes boost funding for skywalk construction. Additionally, a higher white-collar employment rate indicates a more modernized economic structure, driving the construction and demand for skywalks [8; 36; 41].  
The urban built environment encompasses five factors: population density, area, user satisfaction, construction of underground walkways, and length-to-width ratio of the block. High-density areas require more access and connectivity to accommodate large volumes of pedestrian traffic [8]; in areas with dispersed populations, aerial pedestrian systems need to address issues such as connectivity, convenience, and attractiveness. The size of the tract area affects the size and layout of the aerial walk system. Larger districts allow the skywalk to function as an efficient transportation mode, connecting various functional areas [5]. User satisfaction can assess the degree of acceptance of the skywalk system by walkers, enabling targeted improvements and optimizations based on walker experiences. As a part of three-dimensional transportation improvement, the demand for aerial walking systems may be equally present in areas where underground walkways are constructed [8; 39], while the aspect ratio of a block affects the design and layout of a skywalk system [3].  
Therefore, this study selects indicators that have a significant impact on skywalk system design, as determined in previous research, in the construction of an evaluation system for conducting subsequent research.