JBA 5m GB Megaraster contains flood hazard data at 5m resolution for all flood sources for Great Britain (river, surface, coastal, groundwater/chalk), including Isle of Man and the Channel Islands. It provides an efficient way to view and interrogate all the information contained in JBA’s 5m resolution flood maps for any location rather than having to analyse each spatial layer separately.

JBA 5m GB Megaraster provides scores from the JBA Matrix Score system for every 5-metre grid cell, for every flood source, for multiple return periods (annual exceedance probabilities). It also presents flood extent and banded depth data and summarises the likelihood of flood depth/intensity with a combined flood score (0/low to 53/high).

- Separate raster datasets are provided for defended and undefended scenarios
- Data for Northern Ireland on request
- Data updated annually

Note: The 'JBA Matrix' is a series of tables providing qualitative ratings of flood hazard and is used as an indicator of flood hazard at a given location.