Data overview
Basic principles
Boundary-Line is the key dataset of administrative and voting boundaries in Great Britain. It is a representation in computer-readable form of a specialist large-scale map, including real-world objects, which may be tangible (such as the mean high water mark) or intangible (such as a district boundary).
GIS software provides the functionality to store, manage and manipulate this digital map data. The properties of the data make it suitable as a key base for users wishing to develop applications. Boundary-Line is also suitable for use within other digital mapping systems. It's coordinated on the National Grid, which allows for the easy superimposition of other datasets.
Polygons are continuous areas defined by sets of bounding closed lines. They are representational of areas, such as electoral wards, and have relationships to administration collection features in order to convey descriptive characteristics of the polygon. These are explicit within the data and can be viewed and manipulated with appropriate software.
Boundary-Line data source
Boundary-Line is currently updated by mapping against OS VectorMap Local (1:10 000 scale) and, in certain cases, large-scale sources.
Boundary-Line features
A list of the features within Boundary-Line includes:
Area measurements
Civil parish (England) and community (Wales)
County
Distinctive names
District
Electoral division (county and unitary)
English region
Extent of the realm (EOR): either mean low water mark (England and Wales), mean low water springs mark (Scotland) or seaward boundary extensions
Greater London Authority
Greater London Authority Assembly constituencies (the London proportional representation voting areas)
GSS codes in England, Wales and Scotland for all units, with the exception of Greater London Authority, county electoral divisions and non-civil-parish areas
London borough (including the county of the City of London)
Mean high water mark (England and Wales) and / or mean high water springs mark (Scotland): both are abbreviated to MHW in product documentation
Metropolitan district
Scottish parliamentary constituency and electoral region
Unitary authority
Unique administrative unit, link and polygon identifiers
Ward (district, unitary, metropolitan and London borough)
Welsh Parliament constituency and electoral region
Westminster (parliamentary) constituency
Supplementary layers in Boundary-Line
There are several supplementary layers included alongside the main Boundary-Line product. These supplementary layers sit separately to the main GB Boundary-Line folder and are included as separate directories in the shapefile and MapInfo TAB file formats.
Features included as supplementary in the supplementary directory are:
Historical counties
Ceremonial counties
Historical European regions (frozen as of 1 April 2021)
Country
Boundary-Line folder directory structure
Last updated
