Boundary-Line – October 2024 release note

This release note provides information about the October 2024 release of Boundary-Line.

Boundary-Line – June 2024 release note

This release note provides information about the June 2024 release of Boundary-Line.

Feature classes

Boundary-Line has three feature classes:

• Administrative units with attributes

• Polygon features with attributes

• Polyline features with attributes

Each feature has the following component:

• Feature attribute data

Each geometric feature has an additional component:

• Feature position

Feature position

The geometry of map features is defined in terms of coordinates. All coordinates used in Boundary-Line are based on the Ordnance Survey National Grid (NG) coordinate referencing system and are quoted to a 0.1 m resolution. Despite this, Boundary-Line data can be no more accurate than its source, primarily the generalised 1:10 000 scale mapping.

There will be positional differences between the boundaries in Boundary-Line and Ordnance Survey large-scale topographic products. This is due to the large-scale products being surveyed to a higher degree of accuracy and associated to ground surface features, at scales such as 1:1 250 and 1:2 500.

Boundary-Line has been created as a more generalised set of administrative and electoral boundaries for the whole of Great Britain. It has been digitised against Ordnance Survey (generalised) 1:10 000 scale OS VectorMap Local mapping. The process of generalising for 1:10 000 scale mapping may have caused certain features to be moved from their true ground position for the purposes of map clarity. The result being that Boundary-Line and large-scale boundaries will not always be coincident.

Feature attribute data

An attribute is the descriptive characteristic of a feature, that is, a non-spatial element. In Ordnance Survey map data terms, an attribute can be a feature type (these are character codes), or a distinctive name, number or code, for example, Bassett Ward or 145.232 hectares.

Area codes

Each administrative unit is classified by means of an area code (AC). These area codes are allocated when each feature is initially interpreted and captured from source. This means that a county is distinguished from a ward by the area code allocated to it. The polygon features can be classified by tracing their relationships to administrative units. Consequently, links can be classified by tracing their relationships to polygons.

Other attributes

It is possible, with appropriate software, for you to add other names or values of your own choice as attributes of features.

Unique identifiers for link and polygon

There are two identifiers in Boundary-Line that help you identify features, and which are provided to create consistent references between successive releases of Boundary-Line data. They are unique within each feature type throughout the whole dataset and maintained through successive annual updates. These identifiers are never modified – only created or deleted. If a feature is deleted from the Boundary-Line database, then the identifier ceases to exist.

The two attributes are LINK_ID and POLYGON_ID.

Text

There is no direct cartographic text in Boundary-Line. Names, area values and GSS codes are held as attributes.

Creating the right environment for data management: The Welsh Environmental Data Interface (WENDI)

Agriculture, forestry and woodland account for 90% of Wales’s land use, generating a wealth of insightful statistical information. The Senedd Cymru / Welsh Parliament uses this data to inform policy, assist decision-making and help deliver a wide range of services to rural communities.

Sharing data across the NHS to improve patient services

NHS North West was established under government policy to strengthen primary care trusts (PCTs) and give GPs greater ability to commission or purchase health services directly for their patients. The organisation replaced the three former strategic health authorities in Cumbria and Lancashire, Cheshire and Merseyside, and Greater Manchester. The Association of Greater Manchester PCTs is taking forward a data analysis and reporting tool called the TIS Analyser, which was developed by Greater Manchester health organisations as part of the Tactical Information Service (TIS).

accuracy

The closeness of the results of observations, computations or estimates to the true values or the values accepted as being true. Accuracy relates to the exactness of the result and is the exactness of the operation by which the result is obtained.

administrative area

A blanket term used by Ordnance Survey to refer to all public administrative areas, specifically local government management and electoral areas.

administrative unit

A single administrative area.

area

A spatial extent is defined by circumscribing lines that form a closed perimeter that does not intersect itself.

attribute

An attribute is a property of an entity, usually used to refer to a non-spatial qualification of a spatially referenced entity. For example, a name or descriptive code indicating what an entity represents or how it should be portrayed.

boundary

Boundaries define the areas of the various national, local government and some European authorities.

code

An alphanumeric attribute code used in digital map data to describe each feature in terms either of the object surveyed or its representation on the map (or both).

coding

Allocation of a feature code to a feature being created from constituent construction data: points and/or segments; with optional linking to an existing feature of the same feature code.

coordinates

Pairs of numbers expressing horizontal distances along original axes. Alternatively, triplets of numbers measuring horizontal and vertical distances. Row and column numbers of pixels from raw imagery are not considered coordinates for the purpose of the standard.

currency

An expression of the up-to-dateness of data.

data structure

The defined logical arrangement of data as used by a system for data management; a representation of a data model in computer form.

distinctive name

A text feature consisting of a text string(s) which form(s) a proper name.

entity

Something about which data is stored in a databank or database, for example, boundary and name. The data may consist of relationships, attributes, positional and shape information and so on. Often synonymous with feature.

explicit

Data that is directly represented in digital form. For example, the relationship between two objects is explicit if recorded by such means as pointers and does not have to be deduced by further analysis of the data.

feature

An item of detail within a map that can be a point and/or symbol, text or line.

geographical information system (GIS)

A system for capturing, storing, checking, integrating, analysing and displaying data that is spatially referenced to the Earth. This is normally considered to involve a spatially referenced computer database and appropriate application software.

layer

A subset of digital map data selected on a basis other than position. For example, one layer might consist of all features relating to counties and another to wards. Also known as a level.

level

A level corresponds to a single type of administrative unit (for example, a ward or a district) and is conceptual in form. See also layer.

line

A series of connected coordinated points forming a simple feature with homogeneous attribution.

line feature

The spatial abstraction of an object in one dimension. Lines may intersect with other lines. They are defined as a series of two or more coordinate pairs and may be curved or straight. Curved lines consist of a series of very short straight-line segments. As an object abstraction, a line has no width.

link or edge

Links are the representation of line features. They are made up of one or more consecutive

non-intersecting link segments with common attributes between two terminating nodes. Links have no connection with other links except at the start or end, via common (shared) terminating nodes (points). All links contain their terminating coordinates. Links may form the boundaries of polygons and may be shared between polygons.

name

The proper name or label of an object (real world) or feature (object abstraction). The descriptive name might consist of one or more text strings or be an attribute of the object or object abstraction.

National Grid

A unique referencing system that can be applied to all Ordnance Survey maps of Great Britain (GB) at all scales. It is used by Ordnance Survey on all post-war mapping to provide an unambiguous spatial reference in Great Britain for any place or entity whatever the map scale. The National Grid is defined by the OSGB36 spheroid.

object

A collection of entities which form a higher-level entity within a specific data model.

object (real world)

A recognisable discrete part of the real world.

operative date

The date the order was made; not necessarily the day it becomes ‘live and in use’.

origin

The zero point in a system of rectangular coordinates.

polygon

Polygons are a representation of areas. A polygon is defined as a closed line or perimeter completely enclosing a contiguous space and is made up of one or more links. At least one node occurs on the perimeter of a polygon where the bounding link completes the enclosure of the area. There may be many nodes connecting the bounding links of a polygon. Links may be shared between polygons. Polygons may wholly contain other polygons; or be contained within other polygons.

positional accuracy

The degree to which the coordinates define a point’s true position in the world, directly related to the spheroid and/or projection on which the coordinate system is based.

record

A set of related data fields grouped for processing.

rectangular coordinates

Also known as X-Y coordinates and as eastings and northings. These are two-dimensional coordinates that measure the position of any point relative to an arbitrary origin on a plane surface, for example, a map projection.

relative accuracy

The measure of the internal consistency of the positional measurements in a dataset. For many local area purposes (for example, records of utility plant), relative accuracy is more important than absolute accuracy. In this case, accurate measurement of offsets from fixed points is required rather than knowledge of the true position in space.

resolution

A measure of the ability to detect quantities. High resolution implies a high degree of discrimination but has no implication as to accuracy. For example, in a collection of data in which the coordinates are rounded to the nearest metre, resolution is 1 metre, but the accuracy may be ± 5 metres or worse.

segment

A chord defined by two consecutive coordinates in a line string.

Statutory Instrument

An order made by a Minister under delegated power from Parliament. Contains changes to boundary information, the alignment, type or relationship to a named area (amalgamation) or a change of name to an area are made by order.

transfer format

The format used to transfer data between computer systems. In general usage, this can refer not only to the organisation of data, but also to the associated information, such as attribute codes, which are required in order to successfully complete the transfer.

vector

A straight line joining two data points.

The Boundary-Line product supplies the administrative area relationships.

A district is a division of a county; a civil parish is a division of a district. A county is divided for voting purposes into electoral divisions (EDs) and a district is divided for voting purposes into district wards.

Unitary authorities

With the introduction of unitary authorities, there are now two- and three-tier local government hierarchies. The three-tier system remains unchanged. The two-tier system has unitary authorities replacing the county and district levels of administration.

Unitary authorities may be divided into civil parishes or communities (except in Scotland), and unitary authority wards or unitary authority EDs for voting purposes. In Wales, the voting area is the unitary authority ED; in Scotland it is the unitary authority ward and in England it is the unitary authority ward or unitary authority ED.

Metropolitan districts

England also has metropolitan districts; these have no county administration. These districts are divided for voting purposes into metropolitan district wards.

Greater London Authority and London borough

With the introduction of the regional government for London, in this document called the Greater London Authority, the proportional representation voting area for this new administration is the Greater London Authority Assembly constituency. The existing London borough structure also has a relationship with the new Greater London Authority and each London borough is divided for voting purposes into London borough wards.

Scottish Parliament constituency and electoral regions

Scotland is divided into parliamentary constituencies for voting purposes to elect Members of the Scottish Parliament (MSPs). The Scottish Parliament electoral region is a grouping of Scottish Parliament constituencies.

Welsh Parliament constituency and electoral regions

Wales is divided into parliamentary constituencies for voting purposes to elect parliamentary members (MS) to the Welsh Parliament. The Welsh Parliament electoral region is a grouping of Welsh Parliament constituencies.

English regions

The exit of the United Kingdom from the European Union on 01 January 2021 resulted in the repeal of the European Regions as active electoral areas. For the purposes of Boundary Review, the original European Regions in England have been retained as nine English Regions in the Boundary-Line product. A frozen layer of European Region features, preserved as of 01 April 2021, is available as a supplementary historical dataset.

Westminster (parliamentary) constituency

England, Scotland and Wales are divided into parliamentary constituencies for voting purposes to elect members (MPs) to the Westminster Parliament. Parliamentary constituencies are made up of combinations of wards (or electoral divisions in Wales).

Source of Boundary-Line

The original data sources used for the creation of Boundary-Line was Ordnance Survey’s 1:10 000 scale boundary record sheets and OS Landplan digital data.

The data sources now used are Ordnance Survey’s Topographic Data for Natural Changes and Orders, Acts and Statutory Instruments (SIs).

Update currency

Boundary-Line is updated twice a year, in spring and autumn. The updated product is a full replacement for all the listed administrative and electoral boundaries. The represented boundaries and administrative unit names are defined and modified by Orders, Acts and Statutory Instruments (SIs). Changes that are operative from the first week of May in the current year of release will be included. Changes to Westminster constituencies that are effective from the date of the next general election will be included as separate files.

Superseded boundaries

Boundaries are no longer shown in Boundary-Line if they have been superseded at the time of the annual snapshot of boundaries that each release of Boundary-Line represents.

Government Statistical Service codes

Revisions to Government Statistical Service (GSS) codes are incorporated into Boundary-Line as soon as practicable after the information is made available to Ordnance Survey.

Tide lines and rivers

Additional coastline reconciliation with the OS Landplan product was introduced in May 2005. Changes to the Boundary-Line tide lines, plus natural and gradual changes to rivers and streams, have been implemented alongside the previous boundary/coast association to enhance the MHW FC0071.

All boundary alignment changes in Boundary-Line will be reported in the Release Note accompanying each release of Boundary-Line.

Resolution

The resolution of the coordinate system is 0.1 m. However, it is not possible to calculate meaningful accuracy limits for Boundary-Line data due to both the graphic nature and scale of the primary source 1:10 000 scale published mapping. Such mapping is subject to limited map generalisation, where an impression of the ground detail is made due to the complexity of the detail and importance of certain features such as roads. This means that boundary alignments are cartographically represented in areas where accurate positional representation would be impossible.

Boundary-Line is derived from the basic scale of 1:10 000. The relationship of boundaries to ground detail mirrors the accuracy achieved by mapping against OS VectorMap Local (1:10 000 scale) and, in certain cases, large-scale sources. A consequence of this is that if Boundary-Line is superimposed upon boundaries in OS MasterMap topographic data, variations in the two alignments will be seen.

Completeness

Completeness is a measure of the correspondence between the real world and the specified data content. During digitising, all Boundary-Line data is checked thoroughly against source documents to ensure as far as reasonably possible that no features have been omitted or misaligned.

Data properties

Boundary-Line is a structured link and polygon dataset. The data comprises three levels of features:

1. The administrative unit has attributes that include the administrative unit’s name and GSS code. The administrative unit feature is classified by means of a feature type. It also has explicit pointers to the polygons that define its area.

2. The polygon includes attributes that define its area value; it also has explicit pointers to the links that chains (or makes up) its edge and may have pointers to holes within the area.

3. The links have a geometry that defines their shape.

Administrative units, polygons and links are assigned unique identifiers for each release of Boundary-Line.

Data structure

Real-world administrative and voting units are modelled and named and have explicit pointers to the polygons that define their area of influence.

Each real-world administrative or electoral voting unit is classified by means of an area code. The polygons are classified indirectly by the administrative or electoral voting unit collection in which they appear. These polygons within the data model also have associated attributes which give the entities meaning, representing the geometric characteristic of an entity with items such as area or a unique identity.

Boundary links are classified indirectly by the polygon chains in which they appear.

Administrative or electoral voting units, polygons and links are assigned unique identifiers for each release of Boundary-Line.

Area features

Area features are polygons with attributes added.

Link features

Links represent all linear features; that is boundaries, extent of the realm (EOR) and mean high water (springs) mark (MHW). All links are broken when they intersect with one another. The first and last coordinate pairs in a link correspond exactly with the end coordinates of the adjoining link(s). Links may comprise up to several thousand line segments.

Coordinate system

The coordinate system is National Grid (NG). The National Grid coordinates are to a resolution of 0.1 metres. This is the resolution of the source data.

Area features are polygons with attributes added.

Feature type attributes

The following sub-sections provide details about the attributes included with this feature type, their data types in the different output formats, and other important metadata about them.

Object ID

Feature identifier added by the software.

• Attribute Name: Not provided (GKPG), OBJECTID (TAB), OBJECTID (Shapefile)

• Multiplicity: [1]

PD ID

Identifier comprising 1 to 10 characters.

• Attribute Name: PD_ID (GKPG), PD_ID (TAB), PD_ID (Shapefile)

• Data Type: char

• Size: 10

• Multiplicity: [1]

County

The name of the county_region that the feature is inside (includes Greater London Authority).

• Attribute Name: County (GKPG), County (TAB), County (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [1]

District borough

The name of the district_borough_unitary_region that the feature is inside.

• Attribute Name: Distric_Bo (GKPG), Distric_Bo (TAB), Distric_Bo (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [1]

Ward

The name of the district_borough_unitary_ward_region that the feature is inside.

• Attribute Name: Ward (GKPG), Ward (TAB), Ward (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [1]

Parish

The name of the parish_region where Area_Description='Civil Parish Or Community' that the feature is inside.

• Attribute Name: Parish (GKPG), Parish (TAB), Parish (Shapefile)

• Data Type: CharacterString

• Size: 100

• Multiplicity: [0..1]

Area features are polygons with attributes added.

Feature type attributes

The following sub-sections provide details about the attributes included with this feature type, their data types in the different output formats, and other important metadata about them.

fid

Feature identifier added by the software.

• Attribute Name: fid (GKPG), Not provided (TAB), Not provided (Shapefile)

• Multiplicity: [1]

Name

The name of the community ward.

• Attribute Name: Name (GKPG), Name (TAB), NAME (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [0..1]

Area description

The classification of the community ward.

• Attribute Name: Area_Description (GKPG), Area_Description (TAB), DESCRIPTIO (Shapefile)

• Data Type: char

• Size: 3

• Multiplicity: [1]

Community

The name of the parish_region that the ward is inside.

• Attribute Name: Community (GKPG), Community (TAB), COMMUNITY (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [1]

File name

The name of district_borough_unitary_region that the community ward is inside; written in UPPERCASE with underscores.

• Attribute Name: File_Name (GKPG), File_Name (TAB), FILE_NAME (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [1]

The following subsections describe the content of the Shapefile, TAB and GKPG supply.

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

Feature type attributes

The following sub-sections provide details about the attributes included with this feature type, their data types in the different output formats, and other important metadata about them.

fid

Feature identifier added by the software.

• Attribute Name: fid (GKPG), Not provided (TAB), Not provided (Shapefile)

• Multiplicity: [1]

Name

Name of the Ceremonial County, Historic County or Historic European Region.

• Attribute Name: Name (GKPG), Name (TAB), NAME (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [1]

Area description

Classification set to Ceremonial County or Historic County or Historic European Region.

• Attribute Name: Area_Description (GKPG), Area_Description (TAB), DESCRIPT0 (Shapefile)

• Data Type: char

• Size: 50

• Multiplicity: [1]

Link ID

Boundary polygon.

• Attribute Name: Not provided (GKPG), Not provided (TAB), LINK_ID (Shapefile)

• Data Type: GM_Surface

Links represent all linear features; that is boundaries, extent of the realm (EOR) and mean high water (springs) mark (MHW). All links are broken when they intersect with one another. The first and last coordinate pairs in a link correspond exactly with the end coordinates of the adjoining link(s). Links may comprise up to several thousand line segments.

Feature type attributes

The following sub-sections provide details about the attributes included with this feature type, their data types in the different output formats, and other important metadata about them.

fid

Feature identifier added by the software.

• Attribute Name: fid (GKPG), Not provided (TAB), Not provided (Shapefile)

• Multiplicity: [0..1]

Shape

Feature geometry.

• Attribute Name: Not provided (GKPG), Not provided (TAB), SHAPE (Shapefile)

• Data Type: Polyline

• Multiplicity: [1]

Feature code

Code value assigned to the Mean High Water Line polyline. This value will always be set to – 0071 as this is the feature code applicable to a Mean High Water Line feature.

• Attribute Name: Feature_Code (GKPG), Feature_Code (TAB), CODE (Shapefile)

• Data Type: char

• Size: 4

• Multiplicity: [1]

Feature description

Description of the boundary feature. Set to ‘High Water Mark’ (HWM)

• Attribute Name: Feature_Description (GKPG), Feature_Description (TAB), DESCRIPT0 (Shapefile)

• Data Type: char

• Size: 21

• Multiplicity: [1]

File name

Name of the boundary polygon that the line is contained by; written in UPPERCASE with underscores.

• Attribute Name: File_Name (GKPG), File_Name (TAB), FILE_NAME (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [1]

Feature serial number

Serial number applied to the polyline feature during the production of the product.

• Attribute Name: Feature_Serial_Number (GKPG), Feature_Serial_Number (TAB), NUMBER (Shapefile)

• Data Type: Integer (TAB), Number (Shapefile)

• Size: n/a (TAB), 11 (Shapefile)

• Multiplicity: [1]

Global link ID

A maintained sequential integer identifier that is unique, except for records with duplicate geometry referencing multiple boundary polygons.

• Attribute Name: Global_Link_ID (GKPG), Global_Link_ID (TAB), LINK_ID (Shapefile)

• Data Type: Integer (TAB), Number (Shapefile)

• Size: n/a (TAB), 11 (Shapefile)

• Multiplicity: [1]

Customer Information

• Due to the recent coastline improvements that have been made, there are additional polygon vertices present in this release. If this causes any issues for you when loading the data, please let us know.

• An error was found in the May 2024 v.1 release of the Boundary-Line product. The error meant that expected changes on the ward layer for Worcester City were not present in that release. This has since been corrected and is now present in the Boundary-Line product.

• In the previous May release, due to an internal update to a system, the Unit ID were all been changed. These IDs have now been restored.

• The attribute order found in the Shapefile format of this release have been updated to meet the attribute order stated in the product spec.

Product Enhancements

1. In line with the exit of the United Kingdom from the European Union, the European Region layer has been frozen as of 1 April 2021 (no edits have been made to the European Region extents since 31 December 2020, but there were some minor coastline edits up to 1 April 2021). This frozen layer is available as a supplementary Historical European Region layer within Boundary-Line.

2. For the purposes of Boundary Review, the extents of the European Regions in England have been retained in the Boundary-Line product and will be maintained as an English Region layer.

3. For customers who used the European Region layer to represent a national extent for Scotland and Wales, a new Country Region layer is available as a supplementary layer in Boundary-Line. This will be a maintained layer and represents the national extents of England, Scotland and Wales.

4. Boundary-Line is now released in vector tile (MBTiles) format as of October 2021.

5. Boundary-Line has updated the legal name of the National Assembly for Wales to Senedd Cymru/the Welsh Parliament.

   • The relevant legislation and Statutory Instruments (SIs) can be found here:

     • Legislation 1

     • Legislation 2 (Amended Wales Act(2006) with changed constituency name references)

Data Issues

• The Global_Polygon_ID attribute is not present in the vector tile format of Boundary-Line at this release. All other formats are unaffected by this issue. This will be rectified for the subsequent release of Boundary-Line.

New Westminster Constituency Boundaries

The Westminster Constituency Boundaries created by the National Boundary Commissions were based on the Ordnance Survey Boundary-Line product data in place on 1st December 2020. As this does not take account of any subsequent amendments to this product, there will be some variation between the boundaries displayed in the Boundary Line product and the Final Recommendations:

• The Ordnance Survey has captured the Westminster Constituency features based on the Boundary-Line product electoral boundaries from the latest release and has corrected any minor errors to the Boundary Commission’s final recommendations. The types of corrections made would typically be as a result of administration changes due to electoral reviews, or geographical changes such as to coastline or rivers.

• The Ordnance Survey Westminster Constituency Boundary between Stoke-on-Trent Central and Stoke on Trent North Constituencies has been amended at 26-45 Forest Edge, Sneyd Street Stoke-on Trent, ST6 2PY, and does not follow the boundary between the Moorcroft and Sneyd Green and Birches Head and Northwood electoral Wards. The Ordnance Survey Westminster Constituency boundary has been amended at this location and is consistent with the constituency boundary created by the Boundary Commission for England, this has been carried out to ensure that the properties indicated are located in the correct Westminster Constituency.

• Ordnance Survey Westminster Constituency boundaries and Government Statistic Service (GSS) codes for the Ayr, Carrick and Cumnock / Berwickshire, Roxburgh and Selkirk / Central Ayrshire / Kilmarnock and Loudoun / West Aberdeenshire and Kincardine constituencies were amended following consultation with the Boundary Commission for Scotland and Government of Scotland.

• The boundaries of these Westminster constituencies have been amended to ensure the consistency with local electoral boundaries, and as no electors were involved in any changes this did not affect the electoral totals. To indicate that these constituencies had been amended and were no longer the same as the current constituencies (dated 2007), and to prevent any confusion, new GSS codes were allocated to provide a unique identifier for the new parliamentary constituencies.

Statutory Instruments (SI) and non-SI changes in June 2024 Boundary-Line release

England

Changes not incorporated into the June 2024 Boundary-Line update

Residual Statutory Instruments (SIs) and non-SIs Boundary-Line only represents the boundaries that are currently operational; future dated or unsigned SIs will not be included. This ensures that the boundary information currency is correct at the time of the dataset release. SIs that are operational in May and or October but signed off too late for inclusion in the May or October products would be included in the next suitable release.

Boundaries that relate to Government Office Region

Each table summarises the County, Unitary Authority and Metropolitan District boundaries within each Government Office Region.

Government Office Region: East of England

• Bedford

• Central Bedfordshire

• Cambridgeshire county

• Essex county

• Hertfordshire county

• Norfolk county

• Suffolk county

• City of Peterborough

• Luton

• Southend-on-Sea

• Thurrock

Government Office Region: East Midlands

• Derbyshire county

• Leicestershire county

• Lincolnshire county

• Northamptonshire county

• Nottinghamshire county

• City of Derby

• City of Leicester

• City of Nottingham

• Rutland

Government Office Region: London

• Kingston upon Thames London borough

• Croydon London borough

• Bromley London borough

• Hounslow London borough

• Ealing London borough

• Havering London borough

• Hillingdon London borough

• Harrow London borough

• Brent London borough

• Barnet London borough

• Lambeth London borough

• Southwark London borough

• Lewisham London borough

• Greenwich London borough

• Bexley London borough

• Barking and Dagenham London borough

• City of London

• Enfield London borough

• Waltham Forest London borough

• Redbridge London borough

• Sutton London borough

• Richmond upon Thames London borough

• Merton London borough

• Wandsworth London borough

• Hammersmith and Fulham London borough

• Kensington and Chelsea London borough

• City of Westminster London borough

• Camden London borough

• Tower Hamlets London borough

• Islington London borough

• Hackney London borough

• Haringey London borough

• Newham London borough

Government Office Region: North West

• Cheshire West and Chester

• Cheshire East

• Cumbria county

• Lancashire county

• Bolton metropolitan district

• Bury metropolitan district

• Knowsley metropolitan district

• Liverpool metropolitan district

• Manchester metropolitan district

• Oldham metropolitan district

• Rochdale metropolitan district

• Salford metropolitan district

• Sefton metropolitan district

• Stockport metropolitan district

• St. Helens metropolitan district

• Tameside metropolitan district

• Trafford metropolitan district

• Warrington

• Wigan metropolitan district

• Wirral metropolitan district

• Blackburn with Darwen

• Blackpool

• Halton

Government Office Region: North East

• County Durham

• Northumberland

• Gateshead metropolitan district

• Newcastle upon Tyne metropolitan district

• North Tyneside metropolitan district

• South Tyneside metropolitan district

• Sunderland metropolitan district

• Darlington

• Hartlepool

• Middlesbrough

• Redcar and Cleveland

• Stockton-on-Tees

Government Office Region: Scotland

• Angus

• West Dunbartonshire

• Clackmannanshire

• West Lothian

• Dundee City

• Highland

• East Ayrshire

• Moray

• East Dunbartonshire

• Orkney Islands

• East Renfrewshire

• Na h-Eileanan an Iar

• Falkirk

• Argyll and Bute

• Glasgow City

• Aberdeenshire

• Inverclyde

• Fife

• Midlothian

• Aberdeen City

• North Lanarkshire

• City of Edinburgh

• Perth and Kinross

• East Lothian

• Renfrewshire

• Shetland Islands

• Scottish Borders

• North Ayrshire

• South Lanarkshire

• Dumfries and Galloway

• Stirling

• South Ayrshire

Government Office Region: South East

• Buckinghamshire

• Milton Keynes

• East Sussex county

• Reading

• Hampshire county

• Slough

• Kent county

• The City of Brighton and Hove

• Oxfordshire county

• West Berkshire

• Surrey county

• Windsor and Maidenhead

• West Sussex county

• Wokingham

• Bracknell Forest

• Isle of Wight

• City of Southampton

• City of Portsmouth

• Medway

Government Office Region: South West

• Dorset

• Bournemouth, Christchurch and Poole

• Gloucestershire county

• City of Bristol

• Somerset county

• South Gloucestershire

• Wiltshire

• Swindon

• Devon county

• Torbay

• Cornwall

• North Somerset

• Isles of Scilly

• City of Plymouth

• Bath and North East Somerset

Government Office Region: Wales

• Abertawe – Swansea

• Sir Ddinbych – Denbighshire

• Blaenau Gwent – Blaenau Gwent

• Sir Fynwy – Monmouthshire

• Bro Morgannwg – the Vale of Glamorgan

• Sir Gaerfyrddin – Carmarthenshire

• Caerffili – Caerphilly

• Sir y Fflint – Flintshire

• Casnewydd – Newport

• Tor-faen – Torfaen

• Castell-nedd Port Talbot – Neath Port Talbot

• Wrecsam – Wrexham

• Conwy – Conwy

• Sir Ynys Mon – Isle of Anglesey

• Merthyr Tudful – Merthyr Tydfil

• Gwynedd – Gwynedd

• Pen-y-bont ar Ogwr – Bridgend

• Caerdydd – Cardiff

• Powys – Powys

• Sir Ceredigion – Ceredigion

• Rhondda Cynon Taf – Rhondda Cynon Taff

• Sir Benfro – Pembrokeshire

Government Office Region: West Midlands

• Shropshire

• Dudley metropolitan district

• Staffordshire county

• Sandwell metropolitan district

• Warwickshire county

• Solihull metropolitan district

• Worcestershire county

• Walsall metropolitan district

• Birmingham metropolitan district

• City of Stoke-on-Trent

• City of Wolverhampton metropolitan district

• County of Herefordshire

• Coventry metropolitan district

• Telford and Wrekin

Government Office Region: Yorkshire and the Humber

• North Yorkshire county

• Sheffield metropolitan district

• Barnsley metropolitan district

• Wakefield metropolitan district

• Bradford metropolitan district

• City of Kingston upon Hull

• Calderdale metropolitan district

• East Riding of Yorkshire

• Doncaster metropolitan district

• North East Lincolnshire

• Kirklees metropolitan district

• North Lincolnshire

• Leeds metropolitan district

• York

• Rotherham Metropolitan District

Boroughs

Previously, the reference to boroughs has not been included in the Boundary-Line product. In striving to improve the product and at the request of the end users, the inclusion of a reference to the boroughs will enable users to search within their GIS and locate them more easily. This addition was introduced in October 2006.

These additions only apply to England and affect the districts that have been granted Charters of Incorporation (CoI), unitary authorities that have been created from previous districts with CoI, and metropolitan districts that have borough status. The tables below identify where (B) has been added to the file name and (B) to the boundary data. This addition does not affect the structure or specification of the product and will not impact on your GIS or translation software.

Metropolitan Districts (England) Borough Status: No (N) or Yes (Y)

• BARNSLEY DISTRICT: Y

• BIRMINGHAM DISTRICT: Y

• BOLTON DISTRICT: Y

• BRADFORD DISTRICT: Y

• BURY DISTRICT: Y

• CALDERDALE DISTRICT: Y

• CITY OF WOLVERHAMPTON DISTRICT: Y

• COVENTRY DISTRICT: Y

• DONCASTER DISTRICT: Y

• DUDLEY DISTRICT: Y

• GATESHEAD DISTRICT: Y

• KIRKLEES DISTRICT: Y

• KNOWSLEY DISTRICT: Y

• LEEDS DISTRICT: Y

• LIVERPOOL DISTRICT: Y

• MANCHESTER DISTRICT: Y

• NEWCASTLE UPON TYNE DISTRICT: Y

• NORTH TYNESIDE DISTRICT: Y

• OLDHAM DISTRICT: Y

• ROCHDALE DISTRICT: Y

• ROTHERHAM DISTRICT: Y

• SALFORD DISTRICT: Y

• SANDWELL DISTRICT: Y

• SEFTON DISTRICT: Y

• SHEFFIELD DISTRICT: Y

• SOLIHULL DISTRICT: Y

• SOUTH TYNESIDE DISTRICT: Y

• ST. HELENS DISTRICT: Y

• STOCKPORT DISTRICT: Y

• SUNDERLAND DISTRICT: Y

• TAMESIDE DISTRICT: Y

• TRAFFORD DISTRICT: Y

• WAKEFIELD DISTRICT: Y

• WALSALL DISTRICT: Y

• WIGAN DISTRICT: Y

• WIRRAL DISTRICT: Y

Districts (England) Borough Status: No (N) or Yes (Y)

• ADUR: N

• ARUN: N

• ASHFIELD: N

• BABERGH: N

• BASSETLAW: N

• BLABY: N

• BOLSOVER: N

• BRAINTREE: N

• BRECKLAND: N

• BROADLAND: N

• BROMSGROVE: N

• CANNOCK CHASE: N

• CHERWELL: N

• CHICHESTER: N

• COTSWOLD: N

• DERBYSHIRE DALES: N

• DOVER: N

• EAST CAMBRIDGESHIRE: N

• EAST DEVON: N

• EAST HAMPSHIRE: N

• EAST HERTFORDSHIRE: N

• EAST LINDSEY: N

• EAST SUFFOLK: N

• EPPING FOREST: N

• FENLAND: N

• FOLKESTONE AND HYTHE: N

• FOREST OF DEAN: N

• HARBOROUGH: N

• HARLOW: N

• HART: N

• HORSHAM: N

• HUNTINGDONSHIRE: N

• LEWES: N

• LICHFIELD: N

• MALVERN HILLS: N

• MANSFIELD: N

• MID DEVON: N

• MID SUFFOLK: N

• MID SUSSEX: N

• MOLE VALLEY: N

• NEW FOREST: N

• NEWARK AND SHERWOOD: N

• NORTH DEVON: N

• NORTH EAST DERBYSHIRE: N

• NORTH HERTFORDSHIRE: N

• NORTH KESTEVEN: N

• NORTH NORFOLK: N

• NORTH WEST LEICESTERSHIRE: N

• ROCHFORD: N

• ROTHER: N

• SEVENOAKS: N

• SOUTH CAMBRIDGESHIRE: N

• SOUTH DERBYSHIRE: N

• SOUTH HAMS: N

• SOUTH HOLLAND: N

• SOUTH KESTEVEN: N

• SOUTH NORFOLK: N

• SOUTH OXFORDSHIRE: N

• SOUTH STAFFORDSHIRE: N

• STAFFORDSHIRE MOORLANDS: N

• STRATFORD-ON-AVON: N

• STROUD: N

• TANDRIDGE: N

• TEIGNBRIDGE: N

• TENDRING: N

• THANET: N

• THREE RIVERS: N

• TORRIDGE: N

• UTTLESFORD: N

• VALE OF WHITE HORSE: N

• WARWICK: N

• WEALDEN: N

• WEST LINDSEY: N

• WEST OXFORDSHIRE: N

• WEST SUFFOLK: N

• WYCHAVON: N

• WYRE FOREST: N

• AMBER VALLEY: Y

• ASHFORD: Y

• BASILDON: Y

• BASINGSTOKE AND DEANE: Y

• BOSTON: Y

• BRENTWOOD: Y

• BROXBOURNE: Y

• BROXTOWE: Y

• BURNLEY: Y

• CAMBRIDGE: Y

• CANTERBURY: Y

• CASTLE POINT: Y

• CHARNWOOD: Y

• CHELMSFORD: Y

• CHELTENHAM: Y

• CHESTERFIELD: Y

• CHORLEY: Y

• COLCHESTER: Y

• CRAWLEY: Y

• DACORUM: Y

• DARTFORD: Y

• EASTBOURNE: Y

• EASTLEIGH: Y

• EAST STAFFORDSHIRE: Y

• ELMBRIDGE: Y

• EPSOM AND EWELL: Y

• EREWASH: Y

• EXETER: Y

• FAREHAM: Y

• FYLDE: Y

• GEDLING: Y

• GLOUCESTER: Y

• GOSPORT: Y

• GRAVESHAM: Y

• GREAT YARMOUTH: Y

• GUILDFORD: Y

• HASTINGS: Y

• HAVANT: Y

• HERTSMERE: Y

• HIGH PEAK: Y

• HINCKLEY AND BOSWORTH: Y

• HYNDBURN: Y

• IPSWICH: Y

• KING'S LYNN AND WEST NORFOLK: Y

• LANCASTER: Y

• LINCOLN: Y

• MAIDSTONE: Y

• MALDON: Y

• MELTON: Y

• NEWCASTLE-UNDER-LYME: Y

• NORTH WARWICKSHIRE: Y

• NORWICH: Y

• NUNEATON AND BEDWORTH: Y

• OADBY AND WIGSTON: Y

• OXFORD: Y

• PENDLE: Y

• PRESTON: Y

• REDDITCH: Y

• REIGATE AND BANSTEAD: Y

• RIBBLE VALLEY: Y

• ROSSENDALE: Y

• RUGBY: Y

• RUNNYMEDE: Y

• RUSHCLIFFE: Y

• RUSHMOOR: Y

• SOUTH RIBBLE: Y

• SPELTHORNE: Y

• ST ALBANS: Y

• STAFFORD: Y

• STEVENAGE: Y

• SURREY HEATH: Y

• SWALE: Y

• TAMWORTH: Y

• TEST VALLEY: Y

• TEWKESBURY: Y

• TONBRIDGE AND MALLING: Y

• TUNBRIDGE WELLS: Y

• WATFORD: Y

• WAVERLEY: Y

• WELWYN HATFIELD: Y

• WEST DEVON: Y

• WEST LANCASHIRE: Y

• WINCHESTER: Y

• WOKING: Y

• WORCESTER: Y

• WORTHING: Y

• WYRE: Y

Unitary Authorities (England) Borough Status: No (N) or Yes (Y)

European Statistical Classifications Aligned to Boundary-Line

Information published by the Office for National Statistics (ONS) identifies the European classification system called NUTS (Nomenclature of Units for Territorial Statistics). This information provides a breakdown of UK regions and countries, allowing for a comparable view of economic activity across the European Union.

• NUTS1 – English Government Office Regions, Wales, Scotland and Northern Ireland.

• NUTS2 – 37 areas, mainly groups of counties and unitary authorities.

• NUTS3 – 133 areas, principally individual counties and unitary authorities.

NUTS 1, NUTS 2, NUTS 3, and LAU 1 Areas

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

This section explains the representation of features in Boundary-Line and describes various definitions and exceptions.

Administrative area

This term is used by Ordnance Survey to refer to all public administrative areas. For the Boundary-Line dataset, the following are included under this term:

In England

• County

• Unitary authority

• Metropolitan district

• District

• Civil parish (Note: Depicted if appropriate notification has been received. Not all parishes have councils.)

• English region

• Parliamentary (Westminster) constituency

• Electoral division (of county or unitary authority)

• Ward (of district, metropolitan district, London borough, unitary authority)

• London borough (including the county of the City of London)

• Greater London Authority

• Greater London Authority Assembly constituency

In Wales

• Unitary authority

• Community (Note: Depicted if appropriate notification has been received.)

• Parliamentary (Westminster) constituency

• Electoral division (of unitary authority)

• Welsh Parliament constituency

• Welsh Parliament electoral region

In Scotland

• Unitary authority

• Parliamentary (Westminster) constituency

• Ward (of unitary authority)

• Scottish Parliament constituency

• Scottish Parliament electoral region

Area values

Area values exist for every polygon in Boundary-Line; area values are quoted to the current Department for Communities and Local Government (DCLG) specification of 0.001 hectare. The value is subject to the inherited accuracies of the generalised 1:10 000 scale published mapping used as the source for Boundary-Line.

Boundary

A boundary is the limit of a pre-set and established area whose limit is determined by one or more lines. For example, in Boundary-Line, an administrative unit boundary is represented by a county area boundary.

Ceremonial counties

A ceremonial county is an area that has an appointed Lord Lieutenant and High Sheriff. Ceremonial counties are not explicitly represented in Boundary-Line.

Complex polygons

Complex polygons are polygons that wholly enclose other polygons. They only occur when an administrative unit wholly encloses one or more others at the same level, for example, a rural district surrounding an urban district.

Detached parts

The description ‘Detached (Det)’, only applies to portions of local government or parliamentary constituency areas which are separated from the main area, being completely surrounded by other local government or parliamentary constituency areas and not connected by direct access on the ground.

The description will not be applied to islands or parts of islands in the sea. Detached parts have the same GSS code (where applicable) as the main area.

Divorcement

Part of a boundary separated from another, originally on the same alignment. Divorcements are created by the revision of one boundary and not the other.

The figure above shows a boundary divorcement. The unitary boundary between Vale of Glamorgan and Cardiff has been realigned, whilst the parliamentary (Westminster) constituency boundary has remained in its original position. It is likely that the parliamentary (Westminster) constituency boundary will also be realigned at some time in the future.

Effective date

These are the dates on which an Act, Order or Statutory Instruments are ‘effective’. They may or may not be the same as the operative date or the appointed day or days. The term is particularly applied to parliamentary (Westminster) constituency changes that are effective at the date of the next general election after the operation of the order making change. This is the ‘effective’ date, that is, the date of the proclamation dissolving an existing Parliament and calling a new Parliament.

Exception areas

The following are specific exceptions to the normal rules:

Greater London and the metropolitan counties:

• Greater London covers the area of the 32 London boroughs plus the City and county of the City of London.

• Greater London is no longer a county. The Greater London Authority, which has no authority over the autonomous London boroughs, is held as one named file with all the sub-levels of boundary within it.

• The London boroughs and the City and county of the City of London have been classified as London boroughs.

The metropolitan districts within the former metropolitan counties (disbanded in 1985) are classified as metropolitan districts:

• Greater Manchester

• Merseyside

• South Yorkshire

• West Yorkshire

• Tyne and Wear

• West Midlands

Government Office Regions

Government Office Regions (GORs) in England are not represented as specific boundary features in Boundary-Line; however, the boundaries that are used to define the GORs are represented as English Regions. A full list of the counties and unitary authorities that represent each English Region which the GORs are based on can be found in the Boundary-Line release note.

Honorary titles

Honorary titles granted to local government areas such as city and town are not included in Boundary-Line.

Boroughs in England have been identified, as from the October 2006 release, with (B) in the file name and

(B) in the Name attribute, for example:

The borough (B) will only be depicted on unitary authorities, district and metropolitan districts. This addition is to purely denote which boundaries have borough status in England without creating polygons or altering the specification in any way.

National boundaries

The boundaries between England and Wales and England and Scotland are represented by the boundaries between countries in the supplementary Country layer. These are maintained boundary extents based off local authority boundaries.

Government Statistical Service codes

Government Statistical Service (GSS) codes are a unique system of referencing for administrative units.

All types of units are coded in Boundary-Line except for Greater London Authority, county electoral divisions and non-civil-parish areas. The County ED code for Greater London Authority is set at 999999999. The code is blank when the administrative unit does not have a code, for example, non-civil- parish areas.

The codes are allocated by the Office for National Statistics (ONS) for England and Wales and by the General Register Office for Scotland (GROS) for Scottish areas.

Operative dates

This is a calendar date, given in an Order, Act or Statutory Instrument, on which the specified boundary changes will come into operation. Dates given may be up to four years after the publication of the Order, Act or Statutory Instrument and may apply to any type of boundary other than parliamentary or European regions.

Order, Act or Statutory Instrument

The represented boundaries and administrative unit names are defined and modified by Orders, Acts and Statutory Instruments (SIs). A document signed by the relevant Secretary of State or a local authority letter describing and giving legal authority for boundary changes.

Superseded date

This is the last date on which a boundary was current. Where an effective date applies, the superseded date will be the day before the next dissolution of Parliament.

Boundaries are no longer shown in Boundary-Line if they have been superseded at the time of the annual snapshot of boundaries that each release of Boundary-Line represents.

Survey change

When changes occur to tidelines, rivers or streams caused by natural and gradual forces, any boundaries that are linked to these altered features will move with them. When the movement of a boundary, MHW or EOR alignment in Boundary-Line reflects such changes, this will be noted in the update notes that accompany each release of Boundary-Line.

Unannexed areas

This is an area within the realm that is not included in all the relevant administrative units. The area will remain unannexed until further legislation changes its situation and the polygon represents a hole in that level of administration.

Unitary authorities

Unitary authorities and counties effectively create a contiguous layer of administrative units throughout the whole of Great Britain. They represent single-tier administrations with responsibility for all areas of local government.

Area features are polygons with attributes added.

Feature type attributes

The following sub-sections provide details about the attributes included with this feature type, their data types in the different output formats, and other important metadata about them.

fid

Feature identifier added by the software.

• Attribute Name: fid (GKPG), Not provided (TAB), Not provided (Shapefile)

• Multiplicity: [1]

Shape

Feature geometry.

• Attribute Name: Not provided (GKPG), Not provided (TAB), SHAPE (Shapefile)

• Data Type: Polygon

• Multiplicity: [1]

Name

Name of the administrative area.

• Attribute Name: Name (GKPG), Name (TAB), NAME (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [0..1]

Area code

A code describing the level.

• Attribute Name: Area_Code (GKPG), Area_Code (TAB), AREA_CODE (Shapefile)

• Size: 3

• Multiplicity: [1]

Area description

Full name of the Area_Code.

• Attribute Name: Area_Description (GKPG), Area_Description (TAB), DESCRIPTIO (Shapefile)

• Data Type: char

• Size: 50

• Multiplicity: [1]

File name

Name of the Principal Area which the boundary sits within.

• Attribute Name: File_Name (GKPG), File_Name (TAB), FILE_NAME (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [1]

Feature serial number

Serial Number applied to the Boundary Feature during the production of the product.

• Attribute Name: Feature_Serial_Number (GKPG), Feature_Serial_Number (TAB), NUMBER (Shapefile)

• Data Type: Integer (TAB), Double (Shapefile)

• Size: 11 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Collection serial number

Collection Serial Number applied to the Boundary Feature during the production of the product.

• Attribute Name: Collection_Serial_Number (GKPG), Collection_Serial_Number (TAB), NUMBER0 (Shapefile)

• Data Type: Integer (TAB), Double (Shapefile)

• Size: 11 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Global polygon ID

A globally unique sequential integer-maintained identifier.

• Attribute Name: Global_Polygon_ID (GKPG), Global_Polygon_ID (TAB), POLYGON_ID (Shapefile)

• Data Type: Integer (TAB), Double (Shapefile)

• Size: 11 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Admin unit ID

A globally unique sequential integer-maintained feature identifier. There are two cases where multiple records have the same UNIT_ID:

1. When portions of local government or parliamentary constituency areas are separated from the main area, being completely surrounded by other local government or parliamentary constituency areas and not connected by direct access on the ground. Not applied to islands or parts of islands in the sea. Detached parts have the same attributes as the main area, except the POLYGON_ID and the Name which has a ‘(DET)’ suffix. In all the existing examples, there is exactly one detached part.

2. In Scotland, two examples where the boundary has thousands of parts, so the multi-polygon is broken into simple polygons to make it easier to handle. The examples are the supplementary country_region layer where NAME=‘SCOTLAND_COUNTRY’ and scotland_and_wales_region where NAME='Highlands and Islands PER'.

• Attribute Name: Admin_Unit_ID (GKPG), Admin_Unit_ID (TAB), UNIT_ID (Shapefile)

• Data Type: Integer (TAB), Double (Shapefile)

• Size: 11 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Census code

Set to the Census / GSS Code for the boundary, for example, E10000014.

• Attribute Name: Global_Polygon_ID (GKPG), Global_Polygon_ID (TAB), CODE (Shapefile)

• Data Type: Char

• Size: 9

• Multiplicity: [0..1]

Hectares

Set to the Census / GSS Code for the boundary, for example, E10000014.

• Attribute Name: Hectares (GKPG), Hectares (TAB), HECTARES (Shapefile)

• Data Type: Char

• Size: 9

• Multiplicity: [1]

Non-inland area

Amount of area within the boundary which is not considered ‘inland’. Non-inland areas are calculated by comparing the Boundary-Line polygons with the Mean High Water lines. The value is in hectares and represents the area between the Mean High Water line and the seaward limit of the boundary denoting Mean Low Water.

• Attribute Name: Non_Inland_Area (GKPG), Non_Inland_Area (TAB), AREA (Shapefile)

• Data Type: Decimal (TAB), Double (Shapefile)

• Size: 12 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Area type code

Code depicting whether the boundary is part of a Civil Administration Area, a Civil Voting Area.

• Attribute Name: Area_Type_Code (GKPG), Area_Type_Code (TAB), TYPE_CODE (Shapefile)

• Size: 2

• Multiplicity: [1]

Area type description

Full description of TYPE_CODE.

• Attribute Name: Area_Type_Description (GKPG), Area_Type_Description (TAB), DESCRIPT0 (Shapefile)

• Data Type: Char

• Size: 25

• Multiplicity: [0..1]

Non-area type code

Shouldn’t be populated.

• Attribute Name: Non_Area_Type_Code (GKPG), Non_Area_Type_Code (TAB), TYPE_COD0 (Shapefile)

• Data Type: Char

• Size: 3

• Multiplicity: [0..1]

Non-area type description

Shouldn’t be populated.

• Attribute Name: Non_Area_Type_Description (GKPG), Non_Area_Type_Description (TAB), DESCRIPT1 (Shapefile)

• Data Type: Char

• Size: 36

• Multiplicity: [0..1]

Area features are polygons with attributes added.

Feature type attributes

The following sub-sections provide details about the attributes included with this feature type, their data types in the different output formats, and other important metadata about them.

fid

Feature identifier added by the software.

• Attribute Name: fid (GKPG), Not provided (TAB), Not provided (Shapefile)

• Multiplicity: [1]

Shape

Feature geometry.

• Attribute Name: Not provided (GKPG), Not provided (TAB), SHAPE (Shapefile)

• Data Type: Polygon

• Multiplicity: [1]

Name

Name of the administrative area.

• Attribute Name: Name (GKPG), Name (TAB), NAME (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [0..1]

Area code

A code describing the level.

• Attribute Name: Area_Code (GKPG), Area_Code (TAB), AREA_CODE (Shapefile)

• Data Type: char

• Size: 3

• Multiplicity: [1]

Area description

Full name of the Area_Code.

• Attribute Name: Area_Description (GKPG), Area_Description (TAB), DESCRIPT0 (Shapefile)

• Data Type: char

• Size: 50

• Multiplicity: [1]

File name

Name of the Principal Area which the boundary sits within.

• Attribute Name: File_Name (GKPG), File_Name (TAB), FILE_NAME (Shapefile)

• Data Type: char

• Size: 100

• Multiplicity: [1]

Feature serial number

Serial Number applied to the Boundary Feature during the production of the product.

• Attribute Name: Feature_Serial_Number (GKPG), Feature_Serial_Number (TAB), NUMBER (Shapefile)

• Data Type: Integer (TAB), Double (Shapefile)

• Size: 11 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Collection serial number

Collection Serial Number applied to the Boundary Feature during the production of the product.

• Attribute Name: Collection_Serial_Number (GKPG), Collection_Serial_Number (TAB), NUMBER0 (Shapefile)

• Data Type: Integer (TAB), Double (Shapefile)

• Size: 11 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Global polygon ID

A globally unique sequential integer-maintained identifier.

• Attribute Name: Global_Polygon_ID (GKPG), Global_Polygon_ID (TAB), POLYGON_ID (Shapefile)

• Data Type: Integer (TAB), Double (Shapefile)

• Size: 11 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Admin unit ID

A globally unique sequential integer-maintained feature identifier. There are two cases where multiple records have the same UNIT_ID:

1. When portions of local government or parliamentary constituency areas are separated from the main area, being completely surrounded by other local government or parliamentary constituency areas and not connected by direct access on the ground. Not applied to islands or parts of islands in the sea. Detached parts have the same attributes as the main area, except the POLYGON_ID and the Name which has a ‘(DET)’ suffix. In all the existing examples, there is exactly one detached part.

2. In Scotland, two examples where the boundary has thousands of parts, so the multi-polygon is broken into simple polygons to make it easier to handle. The examples are the supplementary country_region layer where NAME=‘SCOTLAND_COUNTRY’ and scotland_and_wales_region where NAME='Highlands and Islands PER'.

• Attribute Name: Admin_Unit_ID (GKPG), Admin_Unit_ID (TAB), UNIT_ID (Shapefile)

• Data Type: Integer (TAB), Double (Shapefile)

• Size: 11 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Census code

Set to the Census / GSS Code for the boundary, for example, E10000014.

• Attribute Name: Global_Polygon_ID (GKPG), Global_Polygon_ID (TAB), CODE (Shapefile)

• Data Type: Char

• Size: 9

• Multiplicity: [0..1]

Hectares

Set to the Census / GSS Code for the boundary, for example, E10000014.

• Attribute Name: Hectares (GKPG), Hectares (TAB), HECTARES (Shapefile)

• Data Type: Char

• Size: 9

• Multiplicity: [1]

Non-inland area

Amount of area within the boundary which is not considered ‘inland’. Non-Inland Areas are calculated by comparing the Boundary-Line polygons with the Mean High Water lines. The value is in hectares and represents the area between the Mean High Water line and the seaward limit of the boundary denoting Mean Low Water.

• Attribute Name: Non_Inland_Area (GKPG), Non_Inland_Area (TAB), AREA (Shapefile)

• Data Type: Decimal (TAB), Double (Shapefile)

• Size: 12 (TAB), n/a (Shapefile)

• Multiplicity: [1]

Area type code

Code depicting whether the boundary is part of a Civil Administration Area, a Civil Voting Area.

• Attribute Name: Area_Type_Code (GKPG), Area_Type_Code (TAB), TYPE_CODE (Shapefile)

• Size: 2

• Multiplicity: [1]

Area type description

Full description of TYPE_CODE.

• Attribute Name: Area_Type_Description (GKPG), Area_Type_Description (TAB), DESCRIPT0 (Shapefile)

• Data Type: Char

• Size: 25

• Multiplicity: [0..1]

Non-area type code

Shouldn’t be populated.

• Attribute Name: Non_Area_Type_Code (GKPG), Non_Area_Type_Code (TAB), TYPE_COD0 (Shapefile)

• Data Type: Char

• Size: 3

• Multiplicity: [0..1]

Non-area type description

Shouldn’t be populated.

• Attribute Name: Non_Area_Type_Description (GKPG), Non_Area_Type_Description (TAB), DESCRIPT1 (Shapefile)

• Data Type: Char

• Size: 36

• Multiplicity: [0..1]

Boundary-Line provides a representation of the hierarchy of administrative and electoral boundaries and their names for England, Scotland and Wales. Boundary-Line for England and Wales was initially digitised from Ordnance Survey’s boundary record sheets at 1:10 000 scale (or, in some cases, at larger scales).

How to get this product

Access to OS OpenData is free through the OS Data Hub.

Visualise Boundary-Line data online

Boundary-Line provides a representation of the hierarchy of administrative and electoral boundaries and their names for England, Scotland and Wales. Boundary-Line for England and Wales was initially digitised from Ordnance Survey’s boundary record sheets at 1:10 000 scale (or, in some cases, at larger scales).

The Government Statistical Service (GSS) codes are supplied by the Office for National Statistics (ONS) and General Register Office for Scotland (GROS).

Appropriate software is needed to use the data for your intended application.

Boundary-Line benefits

The high specification of Boundary-Line offers you the following benefits:

• Full coverage of Great Britain, supplied as England, Scotland and Wales.

• The key boundary dataset for Great Britain, suited to multiple applications using a geographical information system (GIS) and other digital mapping systems.

• The full hierarchy of boundaries.

• Structured vector format, offering great functionality.

• GSS codes, where available, which allow you to link Boundary-Line polygons with GSS information.

• Area values for every polygon.

• Mean high water (springs) mark, which enables you to build and explicitly identify dry land areas within coastal polygons.

• Documented updates via bi-annual releases allow you to easily identify relevant changes.

• Unique administrative area identifiers are retained at each update, allowing revised boundaries to be related to your existing data.

Applications

Boundary-Line can be used for GIS analysis to support a wide range of business decision-making, such as:

• Political analysis

• Environmental analysis

• Statistical analysis for social or marketing decision-making

• Geo-demographic analysis

• Asset management

• Planning applications

• Legal work

• Reference and research

• Customised graphic output

Available formats

Boundary-Line is available in the following formats:

• Esri shapefile

• MapInfo TAB file

• GeoPackage

• Geography Markup Language (GML)

• Vector tiles (MBTiles)

Supply mechanism

Boundary-Line can be freely downloaded under the Open Government Licence. Data can be downloaded in various formats from the Ordnance Survey Data Hub.

Update schedule

Boundary-Line is updated twice a year, in spring and autumn, allowing a choice as to which update is preferred.

The spring update represents boundaries (as defined and modified by Orders, Acts and Statutory Instruments) at the date of the May local elections.

The autumn update also represents boundaries at the date of the May local elections and is operative from the previous spring / May to autumn / October release.

Unlike changes to other boundaries, changes to Westminster constituency (parliamentary) boundaries do not come into operation on a defined date, and it is therefore difficult to timetable such changes into the spring or autumn updates. Therefore, any forthcoming Westminster constituency (parliamentary) boundary changes that have been approved by Government will be supplied as a separate file (in MapInfo TAB or Esri shapefile formats only) as part of the updates until they are included in the product.

Boundary-Line data is output in a layered structure. This is a simplified file structure whereby the boundaries are supplied as individual files; for example, the county file contains only counties.

The Inner and Middle Temples

The ‘places’ known as ‘The Inner and Middle Temples’ are within the City of London only for some purposes. They are not shown in Boundary-Line, but their areas have been wholly included within the city and its wards for this dataset. There are two distinct areas with other areas held jointly, and the boundaries are so intermixed that they have never been published by Ordnance Survey separately. A record of these boundaries is, however, held in the Boundary Record Library for reference purposes.

Parish/community wards

Divisions of parishes (England) and communities (Wales) not included in Boundary-Line.

Lands common to the Parishes of…

These are areas where the limits of the parishes concerned have not been determined and the area itself is common to (or belongs to) two or more parishes. In Boundary-Line, they are classified as separate parishes with the name LANDS COMMON TO THE PARISHES OF… applied (sometimes abbreviated to LCPs…).

River Dee

The boundary between Wirral metropolitan district in the former county of Merseyside and Cheshire West and Chester unitary authority in the former county of Cheshire and the Flintshire unitary authority area has not been determined, and the line adopted in Boundary-Line is for the purposes of Ordnance Survey only, so that polygons can be created.

River Mersey

Certain sections of the boundary between the former county of Merseyside (containing the metropolitan districts of Liverpool and Wirral), and in the former county of Cheshire, now Cheshire West and Chester, and Halton have never been determined.

For the purposes of Boundary-Line and by agreement with DCLG:

1. The district boundaries of those parts of Cheshire West and Chester that abut the Mersey estuary have been made coincident with the limits of the relevant district’s wards at the centre of the channel at high water (CCHW).

2. The undetermined part of the southern boundary of Liverpool district, in the Mersey estuary, has been made coincident with the limits of that district’s wards at the CCHW.

3. The undetermined part of the county boundary between the former county of Merseyside and the former county of Cheshire in that part of the estuary between the new Cheshire West and Chester and Liverpool has been made coincident with the limits of the wards at the CCHW.

4. The northern limit of the parliamentary constituency of Ellesmere Port and Neston is the mean high-water mark on the south side of the Mersey estuary.

The wards of Windsor Castle

These ‘wards’, which include the personal apartments of the Sovereign have no relevance to the election of councillors to electoral areas and are wholly included within the district of Windsor and Maidenhead and its wards.

Boundary-Line provides a representation of the hierarchy of administrative and electoral boundaries and their names for England, Scotland and Wales. Boundary-Line for England and Wales was initially digitised from Ordnance Survey’s boundary record sheets at 1:10 000 scale (or, in some cases, at larger scales).

The Government Statistical Service (GSS) codes are supplied by the Office for National Statistics (ONS) and General Register Office for Scotland (GROS).

Appropriate software is needed to use the data for your intended application.

This technical specification includes the following sections:

Customer information

• Due to the recent coastline improvements that have been made, there are additional polygon vertices present in this release. If this causes any issues for you when loading the data, please let us know.

• In the May release, due to an internal update to a system, the Unit IDs were all changed. These IDs have now been restored.

• The attribute order found in the Shapefile format of this release have been updated to meet the attribute order stated in the product spec.

Product enhancements

1. In line with the exit of the United Kingdom from the European Union, the European Region layer has been frozen as of 1 April 2021 (no edits have been made to the European Region extents since 31 December 2020, but there were some minor coastline edits up to 1 April 2021). This frozen layer is available as a supplementary Historical European Region layer within Boundary-Line.

2. For the purposes of Boundary Review, the extents of the European Regions in England have been retained in the Boundary-Line product and will be maintained as an English Region layer.

3. For customers who used the European Region layer to represent a national extent for Scotland and Wales, a new Country Region layer is available as a supplementary layer in Boundary-Line. This will be a maintained layer and represents the national extents of England, Scotland and Wales.

4. Boundary-Line is now released in vector tile (MBTiles) format as of October 2021.

5. Boundary-Line has updated the legal name of the National Assembly for Wales to Senedd Cymru/the Welsh Parliament.

a. The relevant legislation and Statutory Instruments (SIs) can be found here:

• (Amended Wales Act(2006) with changed constituency name references)

Data issues

The Global_Polygon_ID attribute is not present in the vector tile format of Boundary-Line at this release. All other formats are unaffected by this issue. This will be rectified for the subsequent release of Boundary-Line.

Statutory Instruments (SI) and non-SI changes in October 2024 Boundary-Line release

England

Changes not incorporated into the October 2024 Boundary‑Line update

Residual Statutory Instruments (SIs) and non-SIs

Boundary-Line only represents the boundaries that are currently operational; future dated or unsigned SIs will not be included. This ensures that the boundary information currency is correct at the time of the dataset release.

SIs that are operational in May and or October but signed off too late for inclusion in the May or October products would be included in the next suitable release.

Boundaries that relate to Government Office Region

Each table summarises the County, Unitary Authority and Metropolitan District boundaries within each Government Office Region.

Government Office Region: East of England

• Bedford

• Suffolk county

• Central Bedfordshire

• City of Peterborough

• Cambridgeshire county

• Luton

• Essex county

• Southend-on-Sea

• Hertfordshire county

• Thurrock

• Norfolk county

Government Office Region: East Midlands

• Derbyshire county

• City of Derby

• Leicestershire county

• City of Leicester

• Lincolnshire county

• City of Nottingham

• Northamptonshire county

• Rutland

• Nottinghamshire county

Government Office Region: London

• Kingston upon Thames London borough

• Enfield London borough

• Croydon London borough

• Waltham Forest London borough

• Bromley London borough

• Redbridge London borough

• Hounslow London borough

• Sutton London borough

• Ealing London borough

• Richmond upon Thames London borough

• Havering London borough

• Merton London borough

• Hillingdon London borough

• Wandsworth London borough

• Harrow London borough

• Hammersmith and Fulham London borough

• Brent London borough

• Kensington and Chelsea London borough

• Barnet London borough

• City of Westminster London borough

• Lambeth London borough

• Camden London borough

• Southwark London borough

• Tower Hamlets London borough

• Lewisham London borough

• Islington London borough

• Greenwich London borough

• Hackney London borough

• Bexley London borough

• Haringey London borough

• Barking and Dagenham London borough

• Newham London borough

• City of London

Government Office Region: North West

• Cheshire West and Chester

• Warrington

• Cheshire East

• Sefton metropolitan district

• Cumbria county

• Stockport metropolitan district

• Lancashire county

• St. Helens metropolitan district

• Bolton metropolitan district

• Tameside metropolitan district

• Bury metropolitan district

• Trafford metropolitan district

• Knowsley metropolitan district

• Wigan metropolitan district

• Liverpool metropolitan district

• Wirral metropolitan district

• Manchester metropolitan district

• Blackburn with Darwen

• Oldham metropolitan district

• Blackpool

• Rochdale metropolitan district

• Halton

• Salford metropolitan district

Government Office Region: North East

• County Durham

• Darlington

• Northumberland

• Hartlepool

• Gateshead metropolitan district

• Middlesbrough

• Newcastle upon Tyne metropolitan district

• Redcar and Cleveland

• North Tyneside metropolitan district

• Stockton-on-Tees

• South Tyneside metropolitan district

• Sunderland metropolitan district

Government Office Region: Scotland

• Angus

• West Dunbartonshire

• Clackmannanshire

• West Lothian

• Dundee City

• Highland

• East Ayrshire

• Moray

• East Dunbartonshire

• Orkney Islands

• East Renfrewshire

• Na h-Eileanan an Iar

• Falkirk

• Argyll and Bute

• Glasgow City

• Aberdeenshire

• Inverclyde

• Fife

• Midlothian

• Aberdeen city

• North Lanarkshire

• City of Edinburgh

• Perth and Kinross

• East Lothian

• Renfrewshire

• Shetland Islands

• Scottish Borders

• North Ayrshire

• South Lanarkshire

• Dumfries and Galloway

• Stirling

• South Ayrshire

Government Office Region: South East

• Buckinghamshire

• Milton Keynes

• East Sussex county

• Reading

• Hampshire county

• Slough

• Kent county

• The City of Brighton and Hove

• Oxfordshire county

• West Berkshire

• Surrey county

• Windsor and Maidenhead

• West Sussex county

• Wokingham

• Bracknell Forest

• Isle of Wight

• City of Southampton

• City of Portsmouth

• Medway

Government Office Region: South West

• Dorset

• Bournemouth, Christchurch and Poole

• Gloucestershire county

• City of Bristol

• Somerset county

• South Gloucestershire

• Wiltshire

• Swindon

• Devon county

• Torbay

• Cornwall

• North Somerset

• Isles of Scilly

• City of Plymouth

• Bath and North East Somerset

Government Office Region: Wales

• Abertawe – Swansea

• Sir Ddinbych – Denbighshire

• Blaenau Gwent – Blaenau Gwent

• Sir Fynwy – Monmouthshire

• Bro Morgannwg – the Vale of Glamorgan

• Sir Gaerfyrddin – Carmarthenshire

• Caerffili – Caerphilly

• Sir y Fflint – Flintshire

• Casnewydd – Newport

• Tor-faen – Torfaen

• Castell-nedd Port Talbot – Neath Port Talbot

• Wrecsam – Wrexham

• Conwy – Conwy

• Sir Ynys Mon – Isle of Anglesey

• Merthyr Tudful – Merthyr Tydfil

• Gwynedd – Gwynedd

• Pen-y-bont ar Ogwr – Bridgend

• Caerdydd – Cardiff

• Powys – Powys

• Sir Ceredigion – Ceredigion

• Rhondda Cynon Taf – Rhondda Cynon Taff

• Sir Benfro – Pembrokeshire

Government Office Region: West Midlands

• Shropshire

• Dudley metropolitan district

• Staffordshire county

• Sandwell metropolitan district

• Warwickshire county

• Solihull metropolitan district

• Worcestershire county

• Walsall metropolitan district

• Birmingham metropolitan district

• City of Stoke-on-Trent

• City of Wolverhampton metropolitan district

• County of Herefordshire

• Coventry metropolitan district

• Telford and Wrekin

Government Office Region: Yorkshire and the Humber

• North Yorkshire county

• Sheffield metropolitan district

• Barnsley metropolitan district

• Wakefield metropolitan district

• Bradford metropolitan district

• City of Kingston upon Hull

• Calderdale metropolitan district

• East Riding of Yorkshire

• Doncaster metropolitan district

• North East Lincolnshire

• Kirklees metropolitan district

• North Lincolnshire

• Leeds metropolitan district

• York

• Rotherham Metropolitan District

Boroughs

Previously, the reference to boroughs has not been included in the Boundary-Line product. In striving to improve the product, and at the request of the end users, the inclusion of a reference to the boroughs will enable users to search within their GIS and locate them more easily. This addition was introduced in October 2006.

These additions only apply to England and affect the districts that have been granted Charters of Incorporation (CoI), unitary authorities that have been created from previous districts with CoI, and metropolitan districts that have borough status. The tables below identify where _ (B) has been added to the file name and (B) to the boundary data. This addition does not affect the structure or specification of the product and will not impact on your GIS or translation software.

Metropolitan Districts (England)

Districts (England)

Unitary Authorities (England)

European statistical classifications aligned to Boundary-Line

Information published by the Office for National Statistics (ONS) identifies the European classification system called NUTS (Nomenclature of Units for Territorial Statistics). This information provides a breakdown of UK regions and countries, allowing for a comparable view of economic activity across the European Union.

• NUTS1 – English Government Office Regions, Wales, Scotland and Northern Ireland.

  • South West

  • South East

  • East of England

  • East Midlands

  • London

  • North West

  • North East

  • Scotland

  • Wales

  • West Midlands

  • Yorkshire and The Humber

• NUTS2 – 37 areas, mainly groups of counties and unitary authorities.

• NUTS3 – 133 areas, principally individual counties and unitary authorities.

South West

South East

East of England

East Midlands

London

North West

North East

Scotland

Wales

West Midlands

Yorkshire and The Humber

Extent of the realm

The external bounding line of the Boundary-Line dataset is the extent of the realm (EOR). This means the boundary extent is digitised on the alignment of the mean low water (springs) (MLWS) for the seaward extent. Boundary-Line does not contain a separate mean low water (springs) (MLWS), only CODE 0071 representing the mean high water (MHW).

The Territorial Waters Jurisdiction Act 1878 and the Territorial Waters Order in Council 1964 confirm that the EOR of Great Britain as used by Ordnance Survey is properly shown to the limit of mean low water for the time being, except where extended by Parliament.

This means that the EOR will be:

• The mean low water mark (mean low water springs in Scotland) except when landward of a seaward extension or as shown in Figure 5a and indicated as Point B.

• The mean high water mark (mean high water springs in Scotland), where coincident with mean low water or mean low water springs, but not when landward of a seaward extension or Point B.

• Point B

• Seaward extensions

In the figure below, the EOR follows mean low water (springs), crossing the estuaries at LWL.

The figure below shows how these features are represented in Boundary-Line.

Foreshore

The foreshore is taken to be the area of land between mean high water (springs) mark and the EOR which will include:

• Tidal water within a seaward extension.

• Tidal water above Point B, to the normal tidal limit (NTL), together with the area between mean high water (springs) mark and the edge of the channel at mean low water (springs).

Mean high water (springs) mark is represented in Boundary-Line by a polyline feature with CODE 0071. Mean low water (springs) mark is not shown, although it is generally coincident with the EOR.

The area of non-inland is referenced within each administrative unit using the NA attribute.

Islands and rocks in the sea

The following rules govern the representation in Boundary-Line of offshore islands and rocks in the sea:

• Offshore rocks and islands will be shown if 0.4 hectares or more in area at high tide.

• Offshore islands with buildings will always be shown, irrespective of size.

Offshore islands or rocks will not be shown if they are:

• Beyond the defined EOR, irrespective of size.

• Covered at high tide.

If an offshore island or rock is shown, it will be contained within all the relevant administrative unit collections.

Mean high water (springs)

The mean high water (springs) mark is shown to NTL.

Areas of salt marsh, mudflats and so on often have very complicated tide lines. For ease of digitising and to reduce data volumes, mean high water may be generalised in these areas (not Scotland).

Mean high water (springs) mark is represented in Boundary-Line by a polyline feature with CODE 0071.

Mean high water (springs) mark is subject to continuous change but the captured alignment of a tide line is a snapshot on one day. It is not practical to revise tide lines very frequently.

Mean low water (springs)

Mean low water (springs) mark is shown as the EOR, except when contained within a seaward extension, when it is then omitted.

Banks of sand, mud, shingle or rock separated from the main line of mean low water (springs), and covered at high tide, are not shown. When there are large areas of these banks separated from the main foreshore by narrow channels, the channels are ignored and the whole bounded by mean low water (springs).

The extension of the line of mean low water (springs) into a channel above Point B becomes edge of channel and is not shown.

Mean low water (springs) mark, and hence EOR is subject to continuous change but the captured alignment of a tide line is a snapshot on one day. It is not practical to revise tide lines very frequently.

Normal tidal limit

The normal tidal limit (NTL) is the point at which the level of a river or stream ceases to be affected by the tidal flow. This point is often an artificial barrier such as a lock or weir.

Pier

A pier under which water flows is not normally considered to be within the realm. There are some cases, however, where a structure has specifically been included within the realm by act or order, in which case mean high water (springs) mark and EOR are shown around the limits of the structure.

Point B

This is the intangible line across a channel where the level of the river meets the level of the sea at low water.

Within large channels or estuaries, Point B is defined on the source documents for Boundary-Line and is therefore shown as the EOR.

In small channels, Point B is not shown on the source documents, so is assumed to be along the general line of low water and is shown as the EOR.

Seaward extensions

These are artificial extensions to the realm that have been made by an Act of Parliament. They extend the local government and parliamentary areas seaward of mean low water (springs) mark.

Structures in the sea

Breakwaters are structures of wood, stone, metal or other material built to break the force of waves. They can be separate from or joined to the mainland. If joined, they are generally included in the local government and parliamentary areas. If separate, they are not part of the local government and parliamentary area unless they are placed therein by legislation of some kind; for example, Plymouth breakwater is included in the local government area, whilst the centre portion of the Portland Harbour breakwater is not.

Permanent or solid structures in the sea, such as the forts in the Solent off Portsmouth Harbour and Brighton Marina, are usually included in local government and parliamentary areas.

INSPIRE compliant metadata in conjunction with UK Location Programme is available to access as either:

Boundary-Line features

This section describes the features for ESRI shapefile, MapInfo TAB and GeoPackage which make up the Boundary-Line product, giving the following information about each attribute:

Name and Definition

The name of the attribute and what it is describing.

Condition

A condition associated with the attribute (Optional).

Attribute Type

The nature of the attribute, for example, a numeric value or a code list value.

Multiplicity

Describes how many times this element is expected to be populated in the data. An attribute may be optional or mandatory within the Boundary-Line product. These are denoted by:

• ‘1’ – Mandatory – There must be a value.

• ‘0..1’ – Optional – If populated, a maximum of one attribute will be returned.

These values may be used in combination.

GeoPackage (GKPG) is an open, standards-based, data format as is defined by the Open Geospatial Consortium (OGC). It is designed to be a lightweight format that can contain large amounts of varied and complex data in a single, easy-to-distribute and ready-to-use file. GeoPackage offers users the following benefits:

• The single file is easy to transfer and offers the end-user a rich experience.

• Attribute names are not limited in length, making the format user-friendly.

• The file size limit is very large at 140 TB*, so lots of data can be easily accommodated.

• It supports raster, vector and database formats, making it a highly versatile solution.

List of layers