Session number – Oral or poster presentation 3D Geological Modelling at the British Geological Survey using the GSI3D software and methodology.

As a national geological survey organisation the British Geological Survey (BGS) has produced paper maps of Britain’s geology at a series of scales for the past 175 years. Over time these have become more detailed with the one-inch (1:63 360) scale being the standard output in the mid 19th Century whereas today 1:10 000 is considered appropriate for modern needs over most of Britain’s landscape. In 1815, twenty years before the establishment of BGS, William Smith was already addressing the need to present the third dimension of the geology as well as the surface arrangement of units on 2D paper maps. Over time, cross-section drawing became more refined, resulting in outputs such as fence, ribbon and block diagrams to reveal the 3D structure, while contoured surfaces or thicknesses (isopachs) were used to show the spatial position of individual units such as major unconformities or sequences. Geological maps often require another geologist to understand them fully; the surveyors’ spatial ideas, models and concepts can never be properly represented in a 2D map output, and so, until recently, much knowledge has been lost to the science and to the users. In 2000 BGS began the translation of their traditional 2D geological map outputs into fully interactive 3D geological models of the subsurface. This was possible because, by 2000, the Survey had digital geological maps at scales effective for modelling (Jackson & Green, 2003), licensed, nationwide high-resolution Digital Terrain Model (DTM) coverage, and databases of both, borehole index and downhole data supported by corporate dictionaries for lithological and stratigraphical terminology