The 1885 UK parliamentary constituencies for Ireland were re-created in 2017 as part of a conference paper delivered at the Southern Irish Loyalism in Context conference at Maynooth University. The intial map only included the territory of the Irish Free State and was created by Martin Charlton and Jack Kavanagh. The remaining six counties of Ulster were completed by Eoin McLaughlin in 2018-19, the combined result is a GIS map of all the parliamentary constituecies across the island of Ireland for the period 1885-1918. The map is available in both ESRI Shapefile format and as a GeoPackage (GPKG). The methodology for creating the constituencies is outlined in detail below.

Methodology

A map showing the outlines of the 1855 – 1918 Constituency boundaries can be found on page 401 of Parliamentary Elections in Ireland, 1801-1922 (Dublin, 1978) by Brian Walker. This forms the basis for the creation of a set of digital boundaries which can then be used in a GIS. The general workflow involves allocating an 1885 Constituency identifier to each of the 309 Electoral Divisions present in the boundaries made available for the 2011 Census of Population data release by CSO. The ED boundaries are available in ‘shapefile’ format (a de facto standard for spatial data transfer). Once a Constituency identifier has been given to each ED, the GIS operation known as ‘dissolve’ is used to remove the boundaries between EDs in the same Constituency. To begin with Walker’s map was scanned at 1200 dots per inch in JPEG form. A scanned map cannot be linked to other spatial data without undergoing a process known as georeferencing. The CSO boundaries are available with spatial coordinates in the Irish National Grid system. The goal of georeferencing is to produce a rectified version of the map together with a world file. Rectification refers to the process of recomputing the pixel positions in the scanned map so that they are oriented with the ING coordinate system; the world file contains the extent in both the east-west and north-south directions of each pixel (in metres) and the coordinates of the most north-westerly pixel in the rectified image.

Georeferencing involves the identification of Ground Control Points – these are locations on the scanned map for which the spatial coordinates in ING are known. The Georeferencing option in ArcGIS 10.4 makes this a reasonably pain free task. For this map 36 GCPs were required for a local spline transformation. The Redistribution of Seats Act 1885 provides the legal basis for the constituencies to be used for future elections in England, Wales, Scotland and Ireland. Part III of the Seventh Schedule of the Act defines the Constituencies in terms of Baronies, Parishes (and part Parishes) and Townlands for Ireland. Part III of the Sixth Schedule provides definitions for the Boroughs of Belfast and Dublin.

The CSO boundary collection also includes a shapefile of Barony boundaries. This makes it possible code a barony in two ways: (i) allocated completely to a Division or (ii) split between two Divisions. For the first type, the code is just the division name, and for the second the code includes both (or more) division names. Allocation of these names to the data in the ED shapefile is accomplished by a spatial join operation. Recoding the areas in the split Baronies is done interactively using the GIS software’s editing option. EDs or groups of EDs can be selected on the screen, and the correct Division code updated in the attribute table. There are a handful of cases where an ED is split between divisions, so a simple ‘majority’ rule was used for the allocation. As the maps are to be used at mainly for displaying data at the national level, a misallocation is unlikely to be noticed. The final set of boundaries was created using the dissolve operation mentioned earlier. There were a dozen ED that had initially escaped being allocated a code, but these were quickly updated. Similarly, a few of the EDs in the split divisions had been overlooked; again updating was painless. This meant that the dissolve had to be run a few more times before all the errors have been corrected.

For the Northern Ireland districts, a slightly different methodology was deployed which involved linking parishes and townlands along side baronies, using open data sources from the OSM Townlands.ie project and OpenData NI.

A PDF map showing the Westminster Parliamentary Constituencies in the United Kingdom as at December 2018. (File Size - 8MB)

This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data.

The results for each candidate standing in all 73 seats in Greater London are available as an Excel file. The data is also presented as an interactive map below.

The files includes election results from the last three parliamentary constituency elections between 2005 to 2015.

The results presented here include turnout, majority and percentage of vote for each candidate that stood in the election that took place on 7 May 2015.

Read the blog, The 2015 election – the numbers behind the result, which analyses some of the results.

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London Maps

The London data is presented in this interactive Instant Atlas report.

UK Maps

Some interactive maps of the UK results have been created using Tableau.

OSNI 50k Parliamentary Constituencies 2008. Published here for OpenData. By download or use of this dataset you agree to abide by the LPS Open Government Data Licence. The boundaries were delineated in 2008 under the Partliamentary Constituencies (Northern Ireland) Order 2008 and used for the 2010 elections.

These are digital boundaries for the system of Constituencies which were and are the units from which Members of Parliament are elected, and which they then represent. The system of county and borough constituencies has early origins but was not systematically mapped until the reforms introduced by the Representation of the People Act in 1832. In 1949 the whole system of county and borough/burgh constituencies was overhauled to achieve greater consistency across the UK and all two-member and non-spatial constituencies were abolished. This file represents the system as it was established following the Boundary Commission Report of 1949.

The Rural-Urban Classification is a Government Statistical Service product developed by the Office for National Statistics; the Department for Environment, Food and Rural Affairs; and the Welsh Assembly Government.Source: Office for National Statistics licensed under the Open Government Licence v.3.0.Contains OS data © Crown copyright 2025 Links below to FAQ, Methodology and User Guide FAQ https://geoportal.statistics.gov.uk/documents/ebfac455db0642afaa5052738ce5c32e/about Methodology https://geoportal.statistics.gov.uk/documents/833a35f2a1ec49d98466b679ae0a0646/about User Guide https://geoportal.statistics.gov.uk/documents/c8e8e6db38e04cb8937569d74bce277a/about

1:1,000,000 raster map showing the parliamentary boundaries of Northern Ireland. A raster map is a static image displayed on screen which is suitable as background mapping. 1:1 000,000 Raster is smallest scale OSNI raster product giving an excellent overview of Northern Ireland. Published here for OpenData. By download or use of this dataset you agree to abide by the Open Government Data Licence.1:1,000,000 raster map showing the 2008 Parliamentary Constituency boundaries of Northern Ireland. This raster is the smallest scale OSNI raster product giving an overview of Northern Ireland.

This map is based on information contained in the WWT 'wetlands for water quality', 'wetlands for carbon storage', 'wetlands for flood resilience' and 'wetlands for urban wellbeing' indicative wetland potential maps. It summarises the combined 'multi-benefit' wetland potential map, which amalgamates these four layers, while accounting for overlaps (i.e. it avoids counting overlapping layers more than once). It is recommended that users view these datasets alongside this layer.This map summarises WWT's combined wetland potential map by Westminster parliamentary constituency as a percentage cover of the constituency area. The absence of mapped wetland potential in a constituency does not necessarily mean there is no potential to create wetlands, nor a lack of issues that wetland solutions could be used to address. Wetland potential was only mapped within 'demand' areas where there is a greater need for wetland solutions.WWT are calling for the creation of 100,000 hectares of new and restored wetlands in the UK by 2050. This map is a part of WWT’s Roadmap to 100,000 hectares project, which aims to assess both the spatial and economic potential for large-scale wetland restoration targeted at tackling some of the key issues faced by UK society. The work has a particular focus on four themes where wetlands can provide solutions, namely (1) wetlands for carbon storage (specifically saltmarsh for blue carbon), (2) wetlands for urban wellbeing, (3) wetlands for flood resilience, and (4) wetlands for water quality. Wetland potential for water quality, carbon storage, flood resilience and urban wellbeing has been mapped.Full methodology can be found here.Attributes:

Heading

Description

NAME

Constituency name

CODE

Constituency identifier

HECTARES

Area of the constituency in hectares

sum_Area_H

Total area of wetland potential in the constituency, for all four wetland potential maps combined, in hectares

Polygon_Co

Total number of wetland potential parcels in the constituency, for all four wetland potential maps combined (number may be arbitrary due to intersects used e.g. to divide parcels by constituencies)

p_percent

Percentage cover of wetland potential in the constituency for all four wetland potential maps combined

A PDF map showing the Scottish Parliamentary Constituencies in Scotland as at December 2022. (File Size - 268 KB)

This file contains the digital vector boundaries for Scottish Parliamentary Constituencies in Scotland as at May 2021. The boundaries available are: (BFC) Full resolution - clipped to the coastline (Mean High Water mark). Contains both Ordnance Survey and ONS Intellectual Property Rights.REST URL of Feature Access Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/Scottish_Parliamentary_Constituencies_May_2021_Boundaries_SC_BFC/FeatureServerREST URL of WFS Server – https://dservices1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/services/Scottish_Parliamentary_Constituencies_May_2021_Boundaries_SC_BFC/WFSServer?service=wfs&request=getcapabilitiesREST URL of MapServer – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/Scottish_Parliamentary_Constituencies_(May_2021)_Boundaries_SC_BFC/MapServer

This file contains the digital vector boundaries for Westminster Parliamentary Constituencies, in the United Kingdom, as at 4th July 2024.The boundaries available are: (BGC) Generalised (20m) - clipped to the coastline (Mean High Water mark).Contains both Ordnance Survey and ONS Intellectual Property Rights.REST URL of Feature Access Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/Westminster_Parliamentary_Constituencies_July_2024_Boundaries_UK_BGC/FeatureServerREST URL of WFS Server –https://dservices1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/services/Westminster_Parliamentary_Constituencies_July_2024_Boundaries_UK_BGC/WFSServer?service=wfs&request=getcapabilitiesREST URL of Map Server –https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/Westminster_Parliamentary_Constituencies_July_2024_Boundaries_UK_BGC/MapServer

This file contains the names and codes for Westminster parliamentary constituencies in the United Kingdom as at 31 December 2020. (File Size - 72 KB) Field Names - PCON20CD, PCON20NM, FIDField Types - Text, TextField Lengths - 9, 41FID = The FID, or Feature ID is created by the publication process when the names and codes / lookup products are published to the Open Geography portal.REST URL of Feature Access Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/Westminster_Parliamentary_Constituencies_Dec_2020_Names_and_2022/FeatureServer

UK Parliament General Election 8 June 2017 results for Paisley and Renfrewshire North and Paisley and Renfrewshire South.

This file is a lookup between electoral wards/divisions, Westminster parliamentary constituencies and local authority districts in the United Kingdom as at 31st December 2018. (File Size - 2 MB)
Field Names - WD18CD, WD18NM, PCON18CD, PCON18NM, LAD18CD, LAD18NM

This file contains the digital vector boundaries for Westminster Parliamentary Constituencies in the UK, as at 31 December 2017. The boundaries available are: Full resolution - extent of the realm (usually this is the Mean Low Water mark but in some cases boundaries extend beyond this to include off shore islands); Contains both Ordnance Survey and ONS Intellectual Property Rights. REST URL of ArcGIS for INSPIRE View Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/Westminster_Parliamentary_Constituencies_(Dec_2017)_UK_BFE/MapServerREST URL of ArcGIS for INSPIRE Feature DownloadService – https://dservices1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/services/Westminster_Parliamentary_Constituencies_Dec_2017_UK_BFE/WFSServer?service=wfs&request=getcapabilitiesREST URL of Feature Access Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/Westminster_Parliamentary_Constituencies_Dec_2017_UK_BFE_2022/FeatureServer

West Midlands Police stop and search data from data.police.uk provides an in-depth view of how, when, and why stop-and-search actions occur across Birmingham, Solihull and Coventry.Data is updated monthly and anonymized to show approximate locations and includes various details: the reason for the stop (know as the object of search), the law under which is was conducted, demographic information such as age and ethnicity as well as gender. Also recorded is the outcome of the search.Data has been enriched by the City Observatory to include additional location data including;WardConstituency (2024)Local authorityFor full details about quality, anonymisation, collection see https://data.police.uk/about/ .

This file contains the digital vector boundaries for Westminster Parliamentary Constituencies in the UK, as at 31 December 2017. The boundaries available are: Full resolution - clipped to the coastline (Mean High Water mark); Contains both Ordnance Survey and ONS Intellectual Property Rights. REST URL of ArcGIS for INSPIRE View Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/Westminster_Parliamentary_Constituencies_(Dec_2017)_UK_BFC/MapServerREST URL of ArcGIS for INSPIRE Feature DownloadService – https://dservices1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/services/Westminster_Parliamentary_Constituencies_Dec_2017_UK_BFC/WFSServer?service=wfs&request=getcapabilitiesREST URL of Feature Access Service – https://services1.arcgis.com/ESMARspQHYMw9BZ9/arcgis/rest/services/Westminster_Parliamentary_Constituencies_Dec_2017_UK_BFC_2022/FeatureServer

A PDF map showing the Scottish Parliamentary Regions in Scotland as at December 2022. (File Size - 226 KB)

This file contains the names and codes for Westminster parliamentary constituencies in the United Kingdom as at 31 December 2016. (File Size - 72 KB)