20211110 16460700 1.0 TRUE BGS_SDTM_1km This dataset is a vector HEX-grid summary map of the original BGS SDTM_V5 dataset. It shows superficial thickness variation across Great Britain, generalised to hexagons of 2.6 sq km size. It has been made to illustrate thickness variation via a free to use (open licence) dataset. British Geological Survey