## 2 Related Work  
### Mental Satisfaction in Pedestrian Navigation  
Research on pedestrian navigation has a long history. Pedestrians always rely on map services to acquire information about their surroundings. In [18], [PERSON] et al. categorized pedestrian needs into three layers based on the perspective of [PERSON]'s theory [31; 32; 33]: physical sense, physiological safety, and mental satisfaction. Some studies contributed to the physical sense ability, such as the visual display method of navigation, and some works focused on accurate route planning and security to provide reliable navigation from the perspective of the physiological safety layer. However, the study of mental satisfaction has been ignored in some cases. Some research focused on satisfaction during navigation; for instance, there are studies utilizing NASA-TLX [34] and user experience questionnaires [35] to measure perceived workload in pedestrian navigation tasks [36; 37; 38].  
However, pedestrian navigation is a complex process, beyond the effect of environmental factors, the pedestrian is affected by many aspects of the navigation system. Among these aspects, the human-machine interface of navigation is one of the necessary aspects that should never be ignored [18]. From silent paper maps to mobile digital maps, the navigation interface influences user behavior in practical cases. Therefore, to enhance pedestrian satisfaction, researchers should also pay attention to user interface design in navigation. Mental satisfaction might be affected by the map interface in wayfinding tasks. For example, in some cases, the navigation performance of pedestrians will be affected by failure to reach a location and missing some points of interest. Some studies on spatial knowledge and information acquisition [39; 40; 41; 42] emphasize the importance of mobile map design. In [43], [PERSON], [PERSON] summarized that the spatial knowledge of places develops in a sequence of three stages or elements: landmark knowledge, route knowledge, and survey knowledge. Survey knowledge means knowledge of two-dimensional layouts and includes the simultaneous interrelations of locations. Spatial knowledge during navigation could help pedestrians establish a cognitive map to perform orientation and navigation confidently.  
[PERSON] [40; 44] categorized wayfinding tasks into three general types based on their purposes: travel between two familiar places, which is labeled a commute; travel into unfamiliar territory to learn about the surrounding environment, which is labeled as exploration; and travel from a familiar place of origin to an unfamiliar destination, which is labeled a quest. He suggested that different types of wayfinding tasks should be distinguished from each other, and that the means used to accomplish wayfinding tasks should be analyzed in terms of their constituent cognitive abilities. In urban exploration, all three wayfinding tasks involve different motivations and needs. For example, if a person lives in an urban area, when he or she wants to explore a familiar or unfamiliar street in that urban area, he or she might perform all three navigation tasks mentioned above. However, mainstream navigation systems usually focus on providing the shortest route for pedestrians from one place to another place. Accurate instructions of this kind displayed on the navigation interface might occupy the attention of pedestrians so that they cannot form a comprehensive understanding of the real world, which might damage the user experience as well. Moreover, sometimes pedestrians do not need accurate route planning and navigation, which may lead to losing enjoyment and even missing some serendipity along the way, and they may view a rough direction with roaming and detours as their preference. Therefore, sometimes it is necessary to provide pedestrians with a holistic view of the spatial distribution of an urban exploration area and respectfully provide a dynamic map interface to assist pedestrians to explore more points of interest.