# Mobile Augmented Reality Application to Evaluate the River Flooding Impact in Coimbra
###### Abstract  
The downtown area of the city of Coimbra, Portugal, is at low altitude and has historically suffered floods that have caused serious economic losses. The present research proposes a mobile augmented reality (MAR) application aimed at visualising the effect of possible scenarios of flooding in an area of higher risk in the city. A realistic 3D model of the city was created, using data extracted with B.Losm and processed through Blender, followed by its integration into Unity with V.V.  
real-time, context-aware flood information through smartphones and AR devices that require low-price entries into the market. Notably, advancements in wearable technologies, such as ANTSs (Augmented Navigation and Tracking Systems), have facilitated real-world implementations beyond the laboratory setup. Fiducial markers and markerless technologies like Vuforia have enabled precise 3D positioning and tracking that are crucial in AR-based applications, museum installations and interactive landscape designs.  
The research methodologies encompass a wide spectrum, from utilising Bishop Project methodologies for triangulation in model space to employing sophisticated numerical flood models like Iber+ and AR-sandbox hybrid simulations. These approaches emphasise the fusion of physical and numerical modelling to simulate flood dynamics, visualise inundations and project potential scenarios with high precision and interactivity. The preference for numerical models in flood risk management lies in their adaptability, accuracy and efficiency in addressing various scenarios. Numerical models also permit the use of the Bathtub model. This model assumes that areas with elevations below a predicted flood level will be inundated. The methodology involves comparing the elevation data of each cell in a digital elevation model (DEM) against a projected sea level rise. Cells with elevations lower than the predicted sea level are considered prone to flooding.Moreover, the exploration extends to the challenges faced by AR and VR technologies, such as potential health-related impacts on users [3], legal issues in mixed reality, and the need for robust simulation algorithms in complex landscapes.  
Coimbra is a mid-sized city in the centre of Portugal, which started to evolve between the Mondego river and a small hill. Past research has already proposed AR solutions for the visualisation of a part of the city of Coimbra [4], although not for flood visualisation. The present work extends such past research and consists of the conception of an MAR application to display the impacted buildings in case of a flood of the Mondego river in Coimbra using a static image target for AR tracking. Machine learning (ML) and analyses of historical weather data and river water height are used together to predict and find, through regression and correlation, a model, to be used to change the river water plane using a function of the monthly average rain precipitation. This model is then incorporated into the final project to build a user-friendly application that allows users to adjust variables through a User Interface (UI) that changes the Mondego river's water height and displays the impact in an AR scene. This application is oriented toward the mainstream user, being suitable for use in the educational domain and museum expositions, among other possible uses.