## 2 Related Works
### AR-Based Systems  
[PERSON] et al. (2019) used AR technology to develop a guidance system for AR museums [29]. This study applied embodied agents and allowed the user to observe a variety of information related to different pieces of art through interaction with an agent. [PERSON] et al. (2019) combined location-based AR and object recognition to develop an intelligent system for tourism [30]. The system was used for navigation, and provided information about sightseeing spots. [PERSON] et al. (2019) proposed an immersive AR application for an outdoor environment [31]. This application merged simulated images with historical and current content. In addition, this study proposed a suitable framework for multi-image tracking for this purpose. The output of this application offered the opportunity to enrich the information concerning the rehabilitation of the visited object. [PERSON] et al. (2018) developed an application that suggested tourist spots such as tourist centers, hotels, restaurants, and attractions [32]. This study employed image processing and used positioning based on the haversine formula to implement AR. The haversine formula [32] applies the geographical position of user, object, and Earth radius, and then uses the spherical law of cosines to estimate the distance between user and object. This application integrates image detection and social media, and visualizes different visited object features such as intensity, ratings, comments, current social media data, and price information using AR. [PERSON] et al. (2020) developed an innovative AR system to improve diver experience while visiting underwater cultural heritage sites [33]. The system employed a hybrid localization method based on markers and inertial sensors. This method first searched for the images of cultural heritage markers stored in the system. Subsequently, the Kalman filter was applied to fuse the position obtained from these markers with the sensor information. Finally, the obtained position was used to position the virtual object for viewing by the diver. [PERSON] et al. (2016) conducted research-related data profiling of AR applications for tourism purposes. This study reviewed the literature to propose a methodology for integrating data, such as user-generated and governmental open datasets, for using mobile AR applications. This was achieved by assessing the structure and ontology of the data to manage the heterogeneous data structure [34]. [PERSON] et al. (2019) proposed research related to using situated visualization for AR based on context data. In this study, a distance-driven interface was applied with collaborative exhibit viewing. In this interface, the distance of the user obtained from user position context determined the information level, and provided detailed information for users in proximity using the AR technology. The system also allowed the user to come closer to explore more detailed information. Furthermore, interactions between users were modeled in the system, which enabled the users to observe other user comments related to a visiting object [35]. [PERSON] et al. (2020) applied context data for virtual content visualization with AR technology. A good example in this study was the ride-sharing accommodation service. In this case, when the tourist approached the pickup location, a virtual sign was displayed at the interface for the pickup location [36].  
Additionally, AR-based systems need customization based on contextual data. This enables the system to act as a rule-based engine to define information properties during visualization based on the user and their environment. Based on these studies, there is a great need for creating situated visualization for AR for tourism, which changes the property of visualization based on the application of contextual data.