The highly accurate terrain map has been acquired over the last two years by US company Intermap Technologies. Called NEXTMap Britain, the countrywide map forms part of an advanced flood prediction system that will enable Norwich Union, the UK’s largest general insurer, to assess flood risk accurately for every individual property.
The need for more accurate flood risk assessment became evident in October 2000 when the floods that took place in the UK cost the Insurance Industry £1bn and Norwich Union Insurance £200m. In England and Wales around 5 million people, in 2 million properties live in areas of flood risk.
Norwich Union wanted to review the severity and frequency of floods and embarked upon building a flood model that could be used across the country for assessing every property liable to flooding. It soon became clear that the existing terrain and elevation data were not accurate enough to provide property by property assessment.
Working closely with Intermap, Norwich Union commissioned a completely new 3D terrain map of the country. Using a Learjet flying at 450mph at an altitude of 20,000 or 28,000 ft, the data is captured with unprecedented accuracy using airborne radar technology. The earth’s surface is mapped to within 0.5 metres in the areas of high population density and 1 metre elsewhere. The result is an enormous digital database with over 8 billion elevation points forming a truly remarkable map called NEXTMap Britain.
NEXTMap Britain products include digital terrain models and an orthorectified radar image(ORI). Every property in Britain can be located precisely within postcode areas and in relation to the flood plain. Using this data within its new flood model, Norwich Union is able to assess individual properties for flood risk based on cycles of 10, 25, 50, 100 and 1000 years.
Intermap partner Getmapping has been appointed as the master reseller for NEXTMap Britain data in the UK.
