## 2 Spatial Orientation and Wayfinding in Metro Station  
Spatial orientation has long been an important issue in the field of environmental psychology. Since the 1980s, there is a growing scholarship focusing on the identification of factors associated with wayfinding behaviors [4; 5; 6]. Among all identified factors, the authors of [7], through a review of existing literature, have distinguished two broad types as follows: user factors and environmental factors (Table 1). The former is concerned with the relationship between the cognitive ability to assimilate spatial information and the navigating behaviors, while the latter is focused on the physical elements that may enhance or reduce the spatial cognition. For the type of user factors, the authors of [8] pointed out that aging is associated with the decline of spatial cognition and is a particularly important issue for studying spatial orientation. By comparing the wayfinding performance of different age groups, it is found that older adults not only demonstrate less effective spatial memory [9], and the ability to pick up environmental information [10] and establish logical association [11], they also need more directional guidance to find their way around. Regarding the environmental factors, the influence of floor plan configuration on wayfinding performance has received the most attention in published literature. Specifically, many studies suggested that in a spatially complex environment there is an observed increase of time needed to perform wayfinding tasks, the number of wrong turns, and the occurrence of backtracking [12; 13; 14]. Despite the rich literature on spatial orientation, most of it is carried out in hospitals, museums, and shopping malls. In the few studies that investigate metro stations, researchers unanimously affirm that the underground multi-level environment is the key \begin{table}
\begin{tabular}{c c c} \hline \hline
**Type** & **Subtype** & **Element** \\ \hline \multirow{4}{*}{User factors} & \multirow{4}{*}{Wayfinding cognition} & Spatial memories, logical association, information pick-up, neuroanatomy, etc. \\ \cline{2-3}  & & Behavioral performance, navigation pattern \\ \cline{2-3}  & \multirow{2}{*}{Wayfinding behavior} & Age, sex, psychological state, culture \\ \cline{2-3}  & & Floor plan configuration, regions, edges, paths, nodes, landmarks \\ \cline{2-3}  & & Environmental cues & Signs, maps, other environmental factors \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Types of wayfinding factors. Figure 1: Typical floor plans of Taipei Metro stations. factor affecting the passengers' wayfinding performance [15]. The authors of [16], by examining the case of two metro stations in Brussels, specified that the main reasons are the absence of direct sunlight and the lack of recognizable spatial features, while the authors of [17] studied the case of Hong Kong, pointing out that most passengers lose their orientation during the vertical travel between different levels. The most common way to minimize the negative influence discussed above is to install directional signs and maps to help the passengers understand their orientation [18]. Nevertheless, to search for directional guidance itself may be a difficult wayfinding task, especially for the passengers with deficits in either mobility or spatial memory. In the recent years, to overcome the issue of spatial disorientation, there is a growing interest among both software developers and academic researchers in applying mobile technology on wayfinding [19]. For example, 3D Wayfinder, developed by 3D Technologies R&D, uses short-range broadcast devices to provide customized digital signage for their users, while NaviLens by Neoisstec is an enhanced kind of QR code that can be scanned to access wayfinding information [20; 21]. Another example is the mobile application of Gate-to-Go proposed by [22]. It uses the reference number of platform screen doors and exit gates as the index to help the passengers locate their destinations and find the shortest routes.