UK TopoJSON, 2014 - 2023

This repo contains scripts and input files to generate a TopoJSON file covering the following geography layers from 2014 up to the present. (You can preview and download individual geographies with this tool).

• uk United Kingdom (K02)
• ctry Countries (E92, N92, S92, W92)
• rgn Regions (E12, N92, S92, W92)
• cty Counties (E10)
• mcty Metropolitan counties (E11)
• cauth Combined authorities (E47)
• utla Upper-tier/unitary authorities (E06, E08, E09, E10, N09, S12, W06)
• ltla Lower-tier/unitary authorities (E06, E08, E07, E09, N09, S12, W06)

The output file contains layers for each of the above geographies. Each area has areacd (GSS code) and areanm (official name) attributes, and may include a start and/or end attribute for filtering by year (only for new or terminated areas).

Running the scripts

First, you will need to install the NodeJS dependencies. Assuming you have NodeJS installed, simply run:

npm install

Next, you will need to run the scripts. This can be done with a single command:

npm run make-topo

You can preview the output locally by running the included Svelte app:

npm run dev

Editing/updating the config

To update geographies for year-on-year mergers of local authorities or terminations of counties, you should only need to edit the /input/changes.csv file.

If you want to make more complex changes (eg. mergers or terminations of other geographies, or additons of new geography types), you will likely also need to edit /input/ltla14_lookup.csv, /scripts/make-lookup.js, and possibly other files.

Other notes

• The base geometries used are 2016 super generalised boundaries for lower-tier/unitary local authorities.
• There were no changes in UK local authorities from 2014 to 2016, so it is assumed that the boundaries are valid from 2014 onwards.
• In 2018 and 2019 minor boundary changes were made to four local authority areas in Scotland. The updates to their GSS codes are included, but the boundaries provided here do not change (the changes would not be discernable at a super-generalised level in any case).
• In 2018, Shepway was renamed Folkestone and Hythe without a change to its GSS code. Only the newer name is used here.