Digital Geological Map Data of Great Britain - 250k (DiGMapGB-250) version 4

Data identifying landscape areas (shown as polygons) attributed with geological names. The scale of the data is 1:250 000 scale providing a generalised geology. Onshore coverage is provided for all of England, Wales, Scotland and the Isle of Man. Data are supplied as two themes: bedrock and linear features (faults), there is no superficial, mass movement or artificial theme available onshore at this scale. Bedrock geology describes the main mass of solid rocks forming the earth's crust. Bedrock is present everywhere, whether exposed at surface in outcrops or concealed beneath superficial deposits or water bodies. Geological names are based on the lithostratigraphic or lithodemic hierarchy. This means rock bodies are arranged into units based on rock-type and geological time of formation. Where rock-types do not fit into the lithostratigraphic scheme, for example intrusive, deformed rocks subjected to heat and pressure resulting in new or changed rock types; then their classification is based on their rock-type or lithological composition. This assesses visible features such as texture, structure, mineralogy. Data identifying linear features (shown as polylines) represent geological faults at the ground or bedrock surface (beneath superficial deposits). Geological faults occur where a body of bedrock has been fractured and displaced by large scale processes affecting the earth's crust (tectonic forces). The faults theme defines geological faults (shown as polylines) at the ground or bedrock surface (beneath superficial deposits). The data are available in vector format (containing the geometry of each feature linked to a database record describing their attributes) as ESRI shapefiles and are available under BGS data licence.

本数据集旨在识别地形区域（以多边形形式呈现），并赋予其地质名称。数据比例尺为1:250000，提供了一般化的地质信息。该数据集覆盖英格兰、威尔士、苏格兰及马恩岛境内陆地。数据以两个主题提供：基岩和线性特征（断层），在此比例尺下，陆地范围内不提供地表、大规模移动或人工主题。基岩地质描述了构成地球地壳的主要固体岩石。基岩无处不在，无论是在地表露头处露出还是在地表沉积物或水体之下隐蔽存在。地质名称基于岩性地层或岩性分层体系。这意味着岩石体根据岩石类型和形成地质时代被划分为不同的单元。当岩石类型不符合岩性地层方案时，例如侵入岩、受热受力而发生变形的岩石，导致新的或改变后的岩石类型；它们的分类则基于其岩石类型或岩性组成。这评估了可见特征，如质地、结构、矿物学。识别线性特征（以折线形式呈现）的数据代表地表或基岩表面（在浅层沉积物之下）的地质断层。地质断层发生在基岩体因影响地壳的大规模过程（构造力）而断裂和位移的地方。断层主题定义了地表或基岩表面（在浅层沉积物之下）的地质断层（以折线形式呈现）。数据以矢量格式（包含每个特征的几何形状及其属性描述的数据库记录）提供，并以ESRI形状文件格式可用，并受英国地质调查局（BGS）数据许可证的约束。