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Map boundaries

Atlas publishes a simplified kommune boundary file so you can draw a map without finding, projecting and key-matching geometry yourself.

https://atlas.sovereignsky.no/geo/kommuner.geojson
formatGeoJSON FeatureCollection, EPSG:4326 (WGS 84 lon/lat)
features357 — every active, non-sentinel kommune in dim_kommune
size~1.7 MB
join keyproperties.kommune_nr — the same zero-padded text as api_v1.dim_kommune.kommune_nr
also carriesproperties.kommune_name, properties.fylke_nr
sourceKartverket / Geonorge, open data

🔴 It is not what Kartverket published​

The boundaries are simplified with Douglas–Peucker to a tolerance of 0.0003°, about 33 m, which keeps 8.5% of the original points — 997,962 down to 84,521. That is what turns 38.6 MB into 1.7 MB.

Fit for: a choropleth or a locator map at national or county scale.

⚠️ Not fit for: area calculation, cadastral work, or deciding which side of a border a point falls on. Near a boundary the simplified line can be tens of metres from the real one, and small islands may be dropped entirely.

🔵 The authoritative geometry is Kartverket's, at Administrative enheter kommuner. If the position of a boundary matters to your answer, use that, not this.

The file states all of this in its own atlas block, so it travels with the data rather than living only on this page.

Why it is a file and not an endpoint​

Full-resolution boundaries are about 38 MB. Serving them through the API would be worse than not having them at all. The file is static, cacheable and downloaded once.

Drawing a map​

kommune_nr needs no cleanup on either side — that is the whole point of taking the kommune list from dim_kommune when the file is built.

const [geo, rows] = await Promise.all([
  fetch('https://atlas.sovereignsky.no/geo/kommuner.geojson').then(r => r.json()),
  fetch('https://api-atlas.urbalurba.com/coverage_gap_barnefattigdom?select=kommune_nr,value_pct')
    .then(r => r.json()),
]);

const byKommune = new Map(rows.map(r => [r.kommune_nr, r.value_pct]));
for (const f of geo.features) {
  f.properties.value = byKommune.get(f.properties.kommune_nr) ?? null;
}
// -> hand `geo` to Leaflet, MapLibre, D3, deck.gl …

⚠️ A null here means the API had no row for that kommune, which is usually suppression, not zero — see indicator_missing_kommuner. Colour those differently from a real low value rather than filling them as 0.

Attribution​

Inneholder data under norsk lisens for offentlige data (NLOD) tilgjengeliggjort av Kartverket.

Refreshing it​

Kommune boundaries change when municipalities merge, which is rare and known in advance.

cd website && node scripts/generate-kommune-geometry.mjs

It reads the active kommune list from Atlas's own dim_kommune, then fetches each boundary from Kartverket. 🔴 If Kartverket cannot serve a kommune that dim_kommune lists, the script fails and writes nothing — a map with silent holes is worse than no map.