Within the marine environment, the EUNIS classification system attempts to define key environmental drivers that describe natural benthic habitats. The hierarchical nature of the system is initially broad, but becomes increasingly complex at finer biological scales such as communities and species. This project addressed the higher EUNIS levels. Each of the contributing physical parameters were split into categories using threshold values defined with the help of benthic ecologists familiar with the relative influence of such factors on seabed biology. Climatologies were confronted to in situ samples and observations to derive most reliable values. Historic data sets were collated, stitched and harmonised into mosaics which comprehensively covered the area of interest. The criteria analysis model was built in the ArcGIS model builder. Raster data layers were fed into the model at their nominal resolutions with automatic resampling producing a final output cell size of 100m.The model was designed to be as automatic as possible, with a view to enable easy update as new data layers come up. Maps were produced both as web products through WMS services and as paper prints with a dedicated symbology.