# Mobile Augmented Reality Application to Evaluate the River Flooding Impact in Coimbra
## 3 State of the Art on Visualisation and Modelling of River Flooding
### Flooding Visualisation  
[PERSON] et al. [6] explained how they used mobile augmented reality to enable users to track the location that is impacted by floods and populate this location with a 3D building geometry for visualisation. The software aspect involved the integration of various components into a cohesive and user-friendly MAR application adaptable to changes. The key tools employed in this phase included Vuforia, WeSenseIT REST server API, and a dataset formatted in JSON. The algorithmic aspect focused on the augmented reality section. Two major concepts used were triangulation, which consisted of using three rays in a model space, and tracking corner for virtual building facades. The authors elucidated the challenges faced with the baseline Vuforia (without additional packages) in outdoor scenarios. They explained that the reliability of the application began at up to 6 m and detailed that the deformation of the image made it difficult for buildings that were close, because their virtual geometries were not really fixed, as well as for the buildings that were far. The visualisation of water height within the application was considered plausible for real-world scenarios and was tested for Fishlake, Doncaster, UK. The paper reported a positive reception among the expert team members, particularly in the context of emergency applications. [PERSON] et al. [7] used a building framework to simulate and visualise flooding in 3D using position-based fluids for real-time flood visualisation and analysis. The framework created contains the geographical information and several parameters for the simulation, such as friction coefficients, storm drain information, precipitation and soil absorption. They stated that historical information is an important parameter for flood modelling and analysis. They developed a software called \"City Maker\", which consisted of a system design to extract 3D urban OSM data and used a custom visualisation pipeline that provided a ready-made simulation environment. They demonstrated the usability of position-based fluids to simulate and visualise flooding events, and also showed that using environmental data through SRTM elevation with a 30 m resolution was enough to  
Figure 2: Monthly average of all months in the year (2000–2024). perform a realistic representation of a study area in river flooding simulations, particularly for the test case of the digital model of Corpus Christi, TX, USA. [PERSON] et al. [8] created an MAR application named DinofelisAR to view a Forum from the Roman Era superimposed over its current ruins. Vuforia was used as the authors stated that they obtained slightly better results for an augmented reality application running outdoors. They also showed that most of the participants, 90 visitors, tested their application and affirmed to feeling more involved when using the MAR application in their visit. One participant who had never known about nor tried AR technology before agreed that AR technology was easy to use. [PERSON] et al. [9] proved two important points for an MAR application: (1) the availability and technological advances of modern smartphones allow for the development of reliable AR experiences that enhance the understanding of historical datasets, and (2) the gamification of their cultural heritage application is gaining increasing value as it engages visitors. AR can also emphasise the interaction with historical datasets and can be complemented by new forms of visualisation and interaction. [PERSON] and [PERSON] [10] used AR and proved that interaction with 3D cartographic visualisation can enable real-time multi-user exercises in flood visualisation. [PERSON] et al. [11] reviewed existing solutions concerning AR in engineering analysis and simulation. They stated that AR visualisation can enhance perception and understanding of the dataset, as it overcomes limitations from VR systems by providing a simple and immediate user interface to a digitally augmented environment.