The 1:250 000 scale offshore geological maps in the UTM series (Universal Transverse Mercator projection) are available digitally as two themes: bedrock geology (DigRock250) and sea-bed sediments (DigSBS250). A partial Quaternary theme is also published and available for digitisation if required.
The overlying column of sea-water imposes major limitations offshore. Whilst it makes it impossible to conduct normal geological mapping it permits other techniques such as ship-board geophysical surveys to be used allowing geological interpretations using evidence not normally available onshore.