High-accuracy Lidar and Flood Model Data for IGN

Blom CGR France, Blom’s subsidiary in France, has signed a contract with IGN, the French National Geographic and Forestry Information Institute, for an airborne Lidar (Light Detection and Ranging) survey and production of flood models in the south of France. This is a huge project for IGN and will cover all areas at risk from flooding. Blom’s data acquisition will start imminently and the project will be completed within one year.

Flooding is a natural disaster that seems to be increasing in both occurrence and its impact on us. Each flood can put at risk homes, infrastructure and more importantly, lives. Last year areas in France saw devastating floods that were the worst since 1827. It is reassuring that flooding and its consequences now can be monitored, and the water flow can be predicted. Airborne Lidar technology provides altitude data with an accuracy that can reach up to 10cm on bare soil, providing an effective and low cost method to use when surveys of large geographical areas are required. These factors result in Lidar being the best technology to use for flood risk mapping.

Producing flood models of areas at risk of flooding is part of an ambitious governmental project for improving the altimetric data base (RGE Alti) of the whole of France during the period 2010-2013.

Blom is able to provide a complete airborne solution, combining laser scanning with aerial imagery. The laser scanner gathers accurate data for terrain modelling while the digital camera provides imagery for quality control of the Lidar point cloud. The imagery is also used to produce orthophotos over the area, providing IGN with a compelling solution to aide their flood mapping campaign.