## 2 Related Work
### Spatial Ability and Workload in Wafinding Task  
Different researchers have investigated the relationship between spatial ability and wayfinding, focusing on either outdoor or indoor navigation. [PERSON] [21] investigated the relationship between mental rotation skills (using the Vandenburg Kuse Mental Rotations test) and college students' wayfinding performance in an outdoor navigation task. The results showed a significant correlation between mental rotation skills and wayfinding performance on a 6-km orienteering task. The study also highlighted sex differences in spatial ability. Similarly, [PERSON] et al. [26] examined the impact of visuo-spatial ability (V-SA) on wayfinding performance. The wayfinding task focused on a route (approximately 360 m long) in the botanical garden of the university. According to the results of their study, participants with high V-SA had better wayfinding performance and different wayfinding behavior than participants with low V-SA. Participants with low V-SA hesitated more during traveling even if traveling time was the same. Moreover, participants with low V-SA adopted a landmark strategy to navigate, whereas people with high V-SA adopted a route or survey strategy. [PERSON] et al. [23] conducted an experiment to analyze the influence of spatial cognition and different information formats (two-dimensional (2D) drawings or a three-dimensional (3D) model) on individual wayfinding in an unfamiliar environment. The wayfinding task focused on indoor navigation from the starting point to checkpoint A and then to checkpoint B within the building. The results showed that 3D models have a positive impact on individual wayfinding. Moreover, participants with a low spatial cognition had a significantly improved success rate when using a 3D model but the success rate of participants with a high spatial cognition was not affected by the information format. However, more research is needed to confirm whether information format such as 3D effectively reduces cognitive demand [23]. Although there are many studies that examine the relationship between spatial ability and wayfinding performance, only a few focus on complex environments with combined indoor-outdoor navigation [39]. Mental workload is another important measurement and subject of interest for wayfinding and navigation tasks. Researchers have investigated the effects on users' mental workload and task performance when navigating through indoor or outdoor environments using different technologies or evaluating the usability of technologies in many application areas [17; 40]. [PERSON] et al. [17] investigated the effect of practice with Mirror-in-the-Sky (MitS) and track-up maps on navigation performance and mental workload (MWL) in a simple navigation task in a virtual environment. According to the results of a three-session experiment, secondary task performance improved, and task completion times, collisions and subjective MWL decreased with practice. The decrease in MWL was larger with MitS as compared with the track-up map. However, the differences between the track-up map and MitS decreased and were negligible as sessions progressed. [PERSON] and [PERSON] [16] studied the impact of four designing factors (map type, map size, zoom function and direction key) as well as gender differences and sense of direction (SOD) ability on the visual wayfinding performance for a simulated electronic map interface for three wayfinding tasks. The research showed that participants with higher SOD scores had faster response times and lower overall workload for the target task. As the response time of participants increases, they experience a higher workload. Moreover, for target and direction tasks, the interaction effect of map type and SOD affect the mean response time. The male participants with good SOD, using a mixed map, and good SOD using E-map had faster mean response times. Whereas females using E-map had faster mean response time.