Two familiar names. One island. A geographical look at where the shops are, who has the stronger listed presence, and a battle for control.
A local rivalry.
An island-wide question.
Release built 4 October 2026
Official listings: 3 October 2026
For years, Centra and SPAR have quietly fought for control of Ireland. Town by town. Forecourt by forecourt. Chicken fillet roll by chicken fillet roll.
So I did the only reasonable thing: mapped the conflict.
This project tracks who controls each town, where the strongholds are, and where the battle remains too close to call.
Welcome to the war room.
Dated inputs, source manifests and content fingerprints.
A canonical store register, reviewed corrections and explicit count eligibility.
Spatial joins, demographic enrichment and straight-line rivalry rankings.
OSM-only candidates stay separate from the counted register.
Windows Task Scheduler runs the local refresh weekly. Website export and copying remain manual; Azure storage and automatic deployment are future work.
Official locators establish the register. Source IDs, coordinate checks and evidence-backed reviews resolve identity and location conflicts. Unconfirmed OSM candidates remain visible as an optional layer, outside the main totals.
Fingerprints detect changed inputs even at the same path. Unchanged content skips rebuilding. New snapshots recheck whether earlier reviews still apply before promotion.
Frozen inputs support replay. Spatial joins and count reconciliation run before atomic publication; a failed build leaves the previous map serving. This release passed 25 quality checks.
Implemented with local Python, GeoPandas, dated files, offline CI tests and a weekly Windows refresh job. The computer must be awake, connected and signed in. Export delivery is a separate website release step; an automatic end-to-end public refresh is not implemented.
Architecture notes (private repository) ↗The map is a place to ask questions. Start wide, pick a rivalry, or follow the route you actually take.
Compare all 32 counties, then explore individual settlements. Rural shops count in county totals too.
Explore nearest-chain territory at 2, 5, 10 or 20 km. A sampled proximity surface, independent of county borders.
Find the nearest eligible shop on each side from a town, supported postcode or map point. Loyalty is optional.
Submit a road journey and compare unique shops within 2 or 5 km of its route. A corridor, not a driving detour.
The nearest pair from opposite chains.
The longest way to another shop on the same side.
Shops inside a rival’s stronghold.
Places with neither chain listed. Other retailers may be there.
Exactly one Centra and one SPAR-family shop.
Four or more on one side, no listed rival.
Every territory has a definition. Every point has a source. Here’s the context that belongs alongside the colours.
Main counts use official chain listings and reviewed evidence, including Food Standards Agency records. SPAR includes EUROSPAR. Locators can be incomplete or stale; a missing listing is not proof that a shop has closed.
In this export, 5 official records still need review and 199 OSM-only candidates are excluded from main totals. 1,289 locations fall inside settlement boundaries; 128 sit outside them.
Settlement boundaries and historical population come from CSO Census 2022 and NISRA Census 2021. Some NI population figures are unavailable; missing values stay missing. County geography uses Tailte Éireann and OSNI, with the six historic NI counties rather than council districts.
1,416 of 1,417 eligible locations are assigned to a county. 1 remains outside the saved county polygons. Rivalry distances are straight-line distances. Front Lines samples a 1 km grid and does not model roads or terrain.
Some source coordinates are inaccurate or disagree with other evidence, which can affect small distance comparisons. A future improvement would add stronger coordinate validation and a Google Maps cross-check before a release is promoted.
A stronghold defaults to at least 75% of the two chains’ stores, with four eligible stores minimum. Contested territory has 40–60% on each side. These are exploratory labels for listed presence.
The analytical snapshot is static. Leaflet and OpenStreetMap tiles need internet access. Town lookups use saved data; a submitted NI postcode goes to Postcodes.io. A submitted road journey sends its endpoints to the OSRM demo service. Eircodes match known store addresses, not a complete national address lookup.
The map retains the original source links, attribution and service limitations. Visitors need no GitHub login or data-platform credentials.
Pipeline run: 20261004T175327Z-f8e32ccc.
Listings dated 3 October 2026; manual review dated 4 October 2026. The bundle was exported from the promoted release and its saved asset hashes were verified.
The map reads a versioned export, independent of the pipeline. Official locator bulk reuse rights remain unconfirmed; public redistribution needs suitable reuse permission or a register built from appropriately licensed sources.
Documentation links point to the private project repository. The explanation and map on this page can be explored without repository access.
Pick a county. Follow a front line.
Find out where your loyalties lie.
Explore the existing map, with county territories, store evidence and six Field Intelligence dispatches.
The interactive map loads when you enter.Counts describe listed presence, not sales or market share. SPAR includes EUROSPAR.
Basemap: © OpenStreetMap contributors. NI postcode searches use Postcodes.io; submitted road journeys use the OSRM demo. Source labels and attribution remain inside the map.
