Introduction to the theme

The OS National Geographic Database (OS NGD) Land Theme contains point, line and polygon features depicting land cover information. These features can be manmade (for example, residential gardens, tennis courts, construction sites) or natural land (for example, heath or rough grassland, marsh, mixed trees). Features which are exclusively associated with buildings, structures, land use, transport, and water are excluded from the OS NGD Land Features Collection and can instead be found in their respective OS NGD features collections: the OS NGD Building Features, Land Use Features, Structure Features, Transport Features, and Water Features Collections.

The OS NGD Land Theme contains some land information data which can also be seen in the OS MasterMap Topography Layer, Sites Layer, and Greenspace Layer products. The data in the theme is the same as that provided by the aforementioned OS products, but it has been structured to be more analytical and consistent across the six OS NGD features collections, allowing you to easily select the specific features you require and delivering greater value to users. For example, in comparison to data in the three aforementioned OS products, the new OS NGD Land Theme data has been enriched with additional attribution, including the following:

  • Geometry change metadata

  • A Description attribute to provide a one-word or simple phrase description of a feature

  • Detailed land use classification

  • Detailed land cover classification

  • Capture specification to give details about the geography of the area a feature resides in (that is, urban, rural, or moorland)

OS NGD Land Theme data contains land cover attribution that describes the physical and biological surface of the land. OS NGD Land Use Theme data contains land use attribution that describes the human or economic activity taking place on areas of land (i.e. how areas of land are being used / their purpose).

Data structure

The OS NGD Land Theme is made up of the Land Features Collection, which in turn is comprised of five feature types: Land, Land Point, Landform, Landform Line, and Landform Point.

Unique identifiers

Two unique identifiers are provided with each feature within the OS NGD Land Theme:

  • OSID (Ordnance Survey Identifier): The primary identifier and unique key for this theme.

  • TOID (Topographic Identifier): An additional secondary identifier which can aid further data linking. TOIDs are an optional attribute and therefore will not always be provided with every feature.

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