Underground mapping with mobile LiDAR for flood modelling
Mobile LiDAR scanners are mapping underground spaces in Belfast to better understand and prepare for coastal flooding. The use of innovative technology provides greater clarity of large flood risk areas for surveyors, through the creation of flood models.
With sea levels predicted to rise 12 inches by 2050, sufficient flood defenses and a better understanding of water flow help to mitigate risk to coastal towns and cities. Globally, LiDAR solutions help to create the foundations for flood modeling of large areas, however, they seldom consider mapping underground spaces. UrbanArk, a joint research project under the US-Ireland research and development program, seeks to change this by using modern LiDAR technologies.
The UrbanArk Project aims to improve resilience and emergency preparedness against coastal flooding in urban centers. Accurately predicting flood behavior is complicated, especially when not accounting for underground spaces. By presenting the research, UrbanArk demonstrates why incomplete data in high-risk areas poses risks to the population.
Research by Dr. Aaron Miller, a Research Assistant at Queens University Belfast, focuses on the acquisition and analysis of static and mobile LiDAR data. Working as part of the UrbanArk project, Dr. Miller captured both above and below-ground data in areas of Belfast using a handheld SLAM scanner from UK tech firm GeoSLAM (A FARO Solution). He further used data from a terrestrial laser scanner, the FARO Focus, to complement his data.
The research took place at three universities: Queens University Belfast, University College Dublin, and New York University. Due to its considerable amount of subsurface space and proximity to the coast, Belfast proved to be an ideal candidate for the research.
Dr. Miller set to work capturing a 1km2 area split across several blocks, covering most of the city center. He scanned each block individually, using GeoSLAMs ZEB Horizon scanner, georeferencing, and merging the final point clouds into one complete dataset. Underground spaces identified and captured in this area include parking lots and basements.
Belfast is an old and bustling port city with tight passageways and streets full of people, which are a concern for data collection. However, the handheld nature of the SLAM scanner meant that Dr. Miller seamlessly transitioned through the tough environments.
With each capture lasting around 7-15 minutes and over 50 scans carried out in total, Dr. Miller now had the data necessary for the next stage of the project. Using the information gathered, UrbanArk refined flood prediction models and developed immersive virtual reality applications as a communication tool to support communities and emergency planners.
Speaking about the project, Dr. Miller says the following:
"The GeoSLAM ZEB Horizon proved itself to be an efficient tool for urban mapping, due to its combination of maneuverability and accuracy. The user-friendly nature of the scanner promotes widespread use, from novice to expert level surveyors."
Dr. Miller has since presented the research at conferences in the USA and Europe, including GeoWeek in Denver and the Geospatial World Forum in Amsterdam.