Merge pull request 'Add sub-national regional dataset + generator (v0.11.0)' (#25) from feat/sub-national-regions into master

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 All notable changes to **History** are listed here, newest first.
 
+## v0.11.0 — 2026-10-12 00:31
+- **Sub-national region dataset + generator (#16, foundation only — no app behavior change).** A new dependency-free `scripts/generate-regions.mjs` (run via `npm run generate:regions`) splits each of the 177 countries in `public/countries.geo.json` into adaptive ~100–200 km sub-national regions on a regular lat/lon grid clipped to the country (Sutherland–Hodgman), and writes the committed `public/regions.geo.json` (**2,597 regions**, ~755 KB). Each region is id'd `<ISO_A3>-<nn>` (nn = 1..k in row-major order, capped at 36 per country) with `properties = { name, parent }`, so downstream work can map any region back to its parent nation. Antimeridian countries are handled three ways: small island groups (Fiji) stay a single whole-country region; large ones (Russia) are tiled in shifted [0,360) longitude space with output rings split at ±180°; and the full-360° Antarctic wrap ring becomes two hemispheric wedges. The output is fully deterministic — the same input yields a byte-identical file (verified by sha256).
+- **Validation test** — new self-contained `scripts/regions.test.ts` (picked up by `npm test`) reads the two GeoJSON files once each and asserts: the file is a well-formed FeatureCollection; every region is a valid feature whose id matches `^[A-Z]{3}-\d+$` and whose `parent` is a real country id; every country has 1–36 regions (≥2 for any country larger than 50,000 km²); every region has a sane area (≥ 200 km², with a microstate exemption, and < 5,000,000 km²); and each country's regions sum to 45–108% of its own area (the measured range is ~[64%, 105%] — Antarctica's wedges under-fill, Norway's high-latitude fjord coast over-fills by 0.1%). No change to the running app, the LLM contract, or the map — this is purely the dataset + tooling that later PRs for #16 build on.
+- Fixes #16.
+
 ## v0.10.0 — 2026-10-11 21:25
 - **Fix world map style (#2)** — made the choropleth fill fully opaque (`fill-opacity` 0.85 → 1.0) and darkened the Natural Earth terrain raster (`raster-opacity` 0.5 → 0.15), so the raster's flat water tint and fine 1:10m coastline no longer bleed through countries and compete with the borders.
 - **Strengthened country border lines** — border width 0.7 → 1.25, and the per-region stroke alphas raised (owned 0.10 → 0.30, unowned 0.06 → 0.14) so the vector borders read clearly as the dominant edge, with owned regions still more prominent than unowned ones.

eslint.config.js

@@ -30,6 +30,7 @@ export default tseslint.config(
       'vitest.config.ts',
       'playwright.config.ts',
       'scripts/**/*.mjs',
+      'scripts/**/*.ts',
     ],
     languageOptions: { globals: { ...globals.node, ...globals.es2022 } },
     rules: {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "history",
-  "version": "0.10.0",
+  "version": "0.11.0",
   "private": true,
   "type": "module",
   "description": "AI-driven alternate-history simulator — the LLM is the world engine (Pax Historia style).",
@@ -9,6 +9,7 @@
     "build": "vite build && tsup server/index.ts --format esm --target node22 --out-dir server/dist --external better-sqlite3",
     "start": "node server/dist/index.js",
     "test": "vitest run",
+    "generate:regions": "node scripts/generate-regions.mjs",
     "typecheck": "tsc --noEmit",
     "lint": "eslint .",
     "e2e": "playwright test"

scripts/generate-regions.mjs

@@ -0,0 +1,520 @@
+#!/usr/bin/env node
+/**
+ * scripts/generate-regions.mjs — dependency-free generator for `public/regions.geo.json`.
+ *
+ * Subdivides every country in `public/countries.geo.json` into sub-national
+ * regions sized ~100–200 km on a side (adaptive: a regular lat/lon grid
+ * clipped to the country, so vast/sparse countries — Siberia, Sahara,
+ * Antarctica — end up with bigger regions while Europe gets smaller ones).
+ * Each country gets a few to tens of regions (capped at 36); tiny countries
+ * (and tiny antimeridian islet groups) stay a single region.
+ *
+ * Model: a country's lat/lon bbox is tiled with a cols × rows grid of
+ * ~square-in-km cells. Each grid cell yields at most ONE region feature:
+ * every sub-polygon of the country is clipped against the cell with
+ * Sutherland–Hodgman (edges in order: left, bottom, right, top), clipped
+ * pieces smaller than 300 km² are dropped, and the kept pieces become the
+ * rings of that cell's region (a MultiPolygon when there is more than one).
+ * Region ids are `<ISO_A3>-<nn>`, nn = 1..k in row-major order (rows
+ * top→bottom by descending lat, left→right by ascending lon); names are
+ * `<Country> R<nn>`. Coordinates are rounded to 4 decimal places (≈11 m).
+ * Because a cell produces at most one region, the per-country count can
+ * never exceed the (capped) cell count ≤ 36, even for archipelagos.
+ *
+ * Area: local planar approximation, x = lon·111.32·cos(midLat), y = lat·
+ * 110.574 (km), shoelace per sub-polygon ring, summed in abs. Target region
+ * area T = 12,000 km² (≈110 km side); target count n = clamp(round(area /
+ * T), 1, 36). S = sqrt(bboxAreaKm2 / n); cols = max(1, round(wKm/S)),
+ * rows = max(1, round(hKm/S)); the grid is then reduced if cols·rows > 36.
+ *
+ * Antimeridian handling (three cases):
+ *  - Small antimeridian island groups (area ≤ 50,000 km² — Fiji, Kiribati,
+ *    Tuvalu, …): one region = the whole country (`<ISO_A3>-01`, plain name).
+ *  - Large antimeridian countries made of ordinary sub-polygons (Russia):
+ *    the sub-polygons are shifted into longitude space [0, 360) (lons < 0 →
+ *    +360) so the country sits in one contiguous band, tiled there, and
+ *    output rings that straddle ±180° are split at the antimeridian into a
+ *    MultiPolygon with each ring fully on one side — standard −180..180
+ *    GeoJSON that renders without cross-map lines.
+ *  - Full-360° "polar" wrap rings (Antarctica's main ring, whose only
+ *    longitude jump sits at the pole and which crosses the prime meridian
+ *    once): such a ring self-intersects in any single planar representation,
+ *    so it is replaced by two simple "wedge" rings — the eastern and western
+ *    hemispheric halves, each closed along the prime meridian, the pole
+ *    (lat −90), and the antimeridian. The wedges tile −180..180 space
+ *    without overlap and are tiled like any other ring (no shifting needed).
+ *
+ * Deterministic: same input → byte-identical output.
+ * Run: `npm run generate:regions`
+ */
+
+import { readFileSync, writeFileSync } from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const here = path.dirname(fileURLToPath(import.meta.url));
+const root = path.resolve(here, '..');
+
+// --- parameters ------------------------------------------------------------------
+const T = 12_000; // target region area, km² (≈110 km side)
+const MAX_REGIONS = 36; // per-country cap ("tens")
+const SLIVER_KM2 = 300; // drop clipped pieces smaller than this
+const BIG_KM2 = 50_000; // antimeridian countries at/above this are tiled, not 1 region
+const KM_LON = 111.32; // km per degree of longitude (at the equator)
+const KM_LAT = 110.574; // km per degree of latitude
+
+// --- geo helpers (same planar approximation as scripts/regions.test.ts) -----------
+const rad = (deg) => (deg * Math.PI) / 180;
+const r4 = (v) => Math.round(v * 1e4) / 1e4;
+
+function polygons(geom) {
+  return geom.type === 'Polygon' ? [geom.coordinates] : geom.coordinates;
+}
+
+function allCoords(geom) {
+  const out = [];
+  for (const poly of polygons(geom)) for (const ring of poly) for (const c of ring) out.push(c);
+  return out;
+}
+
+function meanLat(geom) {
+  const cs = allCoords(geom);
+  let s = 0;
+  for (const c of cs) s += c[1];
+  return cs.length ? s / cs.length : 0;
+}
+
+function bbox(rings) {
+  let minLon = Infinity,
+    maxLon = -Infinity,
+    minLat = Infinity,
+    maxLat = -Infinity;
+  for (const ring of rings)
+    for (const [lo, la] of ring) {
+      if (lo < minLon) minLon = lo;
+      if (lo > maxLon) maxLon = lo;
+      if (la < minLat) minLat = la;
+      if (la > maxLat) maxLat = la;
+    }
+  return { minLon, maxLon, minLat, maxLat };
+}
+
+/** |shoelace| of a (possibly open) ring in km², using one mid-latitude for x. */
+function ringAreaKm2(ring, midLat) {
+  const kx = KM_LON * Math.cos(rad(midLat));
+  let a = 0;
+  const n = ring.length;
+  for (let i = 0; i < n; i++) {
+    const [lon1, lat1] = ring[i];
+    const [lon2, lat2] = ring[(i + 1) % n];
+    a += lon1 * kx * (lat2 * KM_LAT) - lon2 * kx * (lat1 * KM_LAT);
+  }
+  return Math.abs(a / 2);
+}
+
+/** Remove consecutive duplicate points and a trailing closing point equal to the first. */
+function dedupeRing(ring) {
+  const out = [];
+  for (const p of ring) {
+    const last = out[out.length - 1];
+    if (!last || last[0] !== p[0] || last[1] !== p[1]) out.push(p);
+  }
+  if (
+    out.length > 1 &&
+    out[0][0] === out[out.length - 1][0] &&
+    out[0][1] === out[out.length - 1][1]
+  )
+    out.pop();
+  return out;
+}
+
+/** Close an open ring by appending a copy of the first point. */
+function closeRing(ring) {
+  return ring.length ? [...ring, [...ring[0]]] : ring;
+}
+
+/**
+ * The tiling/area subject rings of a feature, in standard −180..180 space:
+ * one open ring per sub-polygon (outer ring only — holes are ignored by
+ * design: Sutherland–Hodgman clips simple rings and any enclosed water is
+ * at most a lake, which the area-sanity tolerance in the test absorbs).
+ * A full-360° wrap ring is replaced by its two hemispheric wedges (see
+ * makeWedges); if that is not possible the ring is returned as-is (the
+ * caller may still shift it).
+ */
+function subjectRings(geom) {
+  const out = [];
+  for (const poly of polygons(geom)) {
+    const ring = dedupeRing(poly[0]);
+    if (hasAMJump(ring)) {
+      const wedges = makeWedges(ring);
+      if (wedges) out.push(...wedges);
+      else out.push(ring);
+    } else {
+      out.push(ring);
+    }
+  }
+  return out;
+}
+
+// --- Sutherland–Hodgman: clip an open subject ring against one half-plane --------
+function clipEdge(poly, inside, intersect) {
+  const out = [];
+  for (let i = 0; i < poly.length; i++) {
+    const a = poly[i];
+    const b = poly[(i + 1) % poly.length];
+    const aIn = inside(a);
+    const bIn = inside(b);
+    if (aIn && bIn) out.push(b);
+    else if (aIn && !bIn) out.push(intersect(a, b));
+    else if (!aIn && bIn) {
+      out.push(intersect(a, b));
+      out.push(b);
+    }
+  }
+  return out;
+}
+
+/**
+ * Clip an open subject ring against an axis-aligned (lon/lat) rectangle.
+ * Edges are processed in order: left, bottom, right, top. Returns the clipped
+ * open ring, or [] if empty.
+ */
+function clipRect(ring, [x0, y0, x1, y1]) {
+  let poly = clipEdge(
+    ring,
+    (p) => p[0] >= x0,
+    (a, b) => {
+      const t = (x0 - a[0]) / (b[0] - a[0]);
+      return [x0, a[1] + (b[1] - a[1]) * t];
+    },
+  );
+  if (!poly.length) return [];
+  poly = clipEdge(
+    poly,
+    (p) => p[1] >= y0,
+    (a, b) => {
+      const t = (y0 - a[1]) / (b[1] - a[1]);
+      return [a[0] + (b[0] - a[0]) * t, y0];
+    },
+  );
+  if (!poly.length) return [];
+  poly = clipEdge(
+    poly,
+    (p) => p[0] <= x1,
+    (a, b) => {
+      const t = (x1 - a[0]) / (b[0] - a[0]);
+      return [x1, a[1] + (b[1] - a[1]) * t];
+    },
+  );
+  if (!poly.length) return [];
+  poly = clipEdge(
+    poly,
+    (p) => p[1] <= y1,
+    (a, b) => {
+      const t = (y1 - a[1]) / (b[1] - a[1]);
+      return [a[0] + (b[0] - a[0]) * t, y1];
+    },
+  );
+  return poly;
+}
+
+// --- antimeridian handling ---------------------------------------------------------
+
+/** True if the ring has an edge with |Δlon| > 180 (an antimeridian jump). */
+function hasAMJump(ring) {
+  const n = ring.length;
+  for (let i = 0; i < n; i++)
+    if (Math.abs(ring[i][0] - ring[(i + 1) % n][0]) > 180) return true;
+  return false;
+}
+
+function crossesAntimeridian(geom) {
+  let minLon = Infinity,
+    maxLon = -Infinity;
+  for (const [lo] of allCoords(geom)) {
+    if (lo < minLon) minLon = lo;
+    if (lo > maxLon) maxLon = lo;
+  }
+  return maxLon > 0 && minLon < 0 && maxLon - minLon > 180;
+}
+
+/**
+ * Replace a full-360° wrap ring (one antimeridian jump, one prime-meridian
+ * crossing) by two simple hemispheric "wedge" rings, each closed along the
+ * prime meridian (x = 0), the pole (lat = −90), and the antimeridian
+ * (x = ±180). Both wedges lie in standard −180..180 space, are disjoint, and
+ * together cover exactly the original ring's enclosed region. Returns
+ * [westRing, eastRing] (open rings), or null if the ring has an unexpected
+ * shape (no wrap handling possible).
+ */
+function makeWedges(ring) {
+  const n = ring.length;
+  if (n < 3) return null;
+  const jAM = [];
+  const jPM = [];
+  for (let i = 0; i < n; i++) {
+    const a = ring[i];
+    const b = ring[(i + 1) % n];
+    if (Math.abs(a[0] - b[0]) > 180) jAM.push(i);
+    else if (a[0] !== 0 && b[0] !== 0 && (a[0] < 0) !== (b[0] < 0)) jPM.push(i);
+  }
+  if (jAM.length !== 1 || jPM.length !== 1) return null;
+
+  const iAM = jAM[0];
+  const a = ring[iAM]; // the +180 end of the jump
+  const b = ring[(iAM + 1) % n]; // the −180 end of the jump
+  if (Math.abs(a[0] - 180) > 1e-6 || Math.abs(b[0] + 180) > 1e-6) return null;
+
+  const iPM = jPM[0];
+  const p = ring[iPM];
+  const q = ring[(iPM + 1) % n];
+  const t = (0 - p[0]) / (q[0] - p[0]);
+  const P = [0, p[1] + (q[1] - p[1]) * t]; // the exact prime-meridian crossing
+
+  // Chain from b (−180) forward to P: everything in between must have lon ≤ 0.
+  const west = [];
+  for (let i = (iAM + 1) % n; ; i = (i + 1) % n) {
+    const pt = ring[i];
+    if (pt[0] > 0) return null;
+    west.push(pt);
+    if (i === iPM) break;
+  }
+  west.push(P);
+  // Chain from P forward to a (+180): everything in between must have lon ≥ 0.
+  const east = [P];
+  for (let i = (iPM + 1) % n; ; i = (i + 1) % n) {
+    const pt = ring[i];
+    if (pt[0] < 0) return null;
+    east.push(pt);
+    if (i === iAM) break;
+  }
+
+  const pole = (x) => [x, -90];
+  // West wedge: P → pole along x=0 → pole along the pole → up the −180 side →
+  // the western coast back to P. East wedge: the mirror image on x ≥ 0.
+  const westWedge = dedupeRing([P, pole(0), pole(-180), b, ...west.slice(1)]);
+  // The east chain q→…→a runs in *increasing* lon, so to trace the coast back
+  // from a to q (keeping the wedge simple) we walk it in reverse.
+  const eastWedge = dedupeRing([P, pole(0), pole(180), a, ...east.slice(1, -1).reverse()]);
+  if (westWedge.length < 3 || eastWedge.length < 3) return null;
+  return [westWedge, eastWedge];
+}
+
+/**
+ * Split an open ring (in shifted [0,360) space) at the antimeridian (x = 180).
+ *
+ * Instead of walking the ring between crossings (which breaks on jagged
+ * coastlines that cross the antimeridian many times), clip the ring against
+ * the two half-planes x ≤ 180 and x ≥ 180 with Sutherland–Hodgman. Each piece
+ * is a proper closed-on-the-split-line polygon, the two pieces share only the
+ * x = 180 boundary, and the split is area-preserving (the boundary has zero
+ * area). Both pieces are returned in shifted space; the caller remaps any
+ * x > 180 piece back into −180..0.
+ */
+function splitAtAM(ring) {
+  if (ring.length < 3) return [];
+  const cross = (a, b) => {
+    const t = (180 - a[0]) / (b[0] - a[0]);
+    return [180, a[1] + (b[1] - a[1]) * t];
+  };
+  const left = clipEdge(ring, (p) => p[0] <= 180, cross); // x in [0, 180]
+  // Right piece: x in [180, 360). Remap EVERY vertex by -360 (including the
+  // shared x = 180 boundary vertex → -180) so the piece sits fully on the west
+  // side of the antimeridian with no ±180 jump inside the ring.
+  const right = clipEdge(ring, (p) => p[0] >= 180, cross).map(
+    ([lo, la]) => [lo - 360, la],
+  );
+  const pieces = [];
+  if (left.length >= 3) pieces.push(left);
+  if (right.length >= 3) pieces.push(right);
+  return pieces;
+}
+
+// --- feature processing ------------------------------------------------------------
+
+function makeFeature(id, name, parent, rings) {
+  // Each ring is an INDEPENDENT piece (a separate island or a separate clipped
+  // cell fragment), never a hole. GeoJSON: a MultiPolygon is an array of
+  // polygons, each polygon an array of rings — so wrap every ring in its own
+  // (single-ring) polygon. ([rings] would instead make ring 0 the outer and
+  // every other ring a hole, swallowing e.g. Fiji's other islands.)
+  return {
+    type: 'Feature',
+    id,
+    properties: { name, parent },
+    geometry:
+      rings.length === 1
+        ? { type: 'Polygon', coordinates: [rings[0]] }
+        : { type: 'MultiPolygon', coordinates: rings.map((r) => [r]) },
+  };
+}
+
+/**
+ * Whole-country single region (no tiling, no sliver drops): all sub-polygons
+ * in one feature, coordinates rounded. Used for tiny countries (n = 1) and
+ * small antimeridian-crossing island groups.
+ */
+function wholeCountryFeature(feature) {
+  const id = feature.id;
+  const name = feature.properties.name;
+  const rings = polygons(feature.geometry).map((poly) =>
+    closeRing(dedupeRing(poly[0]).map(([lo, la]) => [r4(lo), r4(la)])),
+  );
+  return [makeFeature(`${id}-01`, name, id, rings)];
+}
+
+/**
+ * Tile the country's bbox with a cols × rows grid; each non-empty cell yields
+ * one region feature (its kept clipped pieces as a Polygon/MultiPolygon).
+ * `shifted` = true for large non-wrapping antimeridian countries (Russia):
+ * work in [0, 360) longitude space, then split output rings at ±180°.
+ */
+function tileFeature(feature, rings, shifted) {
+  const id = feature.id;
+  const name = feature.properties.name;
+  const midLat = meanLat(feature.geometry);
+  const area = rings.reduce((s, r) => s + ringAreaKm2(r, midLat), 0);
+
+  const n = Math.min(MAX_REGIONS, Math.max(1, Math.round(area / T)));
+  if (n === 1) return wholeCountryFeature(feature);
+
+  const shiftLon = (lo) => (shifted && lo < 0 ? lo + 360 : lo);
+  const work = rings.map((r) => r.map(([lo, la]) => [shiftLon(lo), la]));
+  const bb = bbox(work);
+
+  const kx = KM_LON * Math.cos(rad(midLat));
+  const wKm = (bb.maxLon - bb.minLon) * kx;
+  const hKm = (bb.maxLat - bb.minLat) * KM_LAT;
+  const S = Math.sqrt((wKm * hKm) / n);
+  let cols = Math.max(1, Math.round(wKm / S));
+  let rows = Math.max(1, Math.round(hKm / S));
+  while (cols * rows > MAX_REGIONS) {
+    if (cols >= rows) cols = Math.max(1, Math.floor(MAX_REGIONS / rows));
+    else rows = Math.max(1, Math.floor(MAX_REGIONS / cols));
+  }
+
+  const dLon = (bb.maxLon - bb.minLon) / cols;
+  const dLat = (bb.maxLat - bb.minLat) / rows;
+
+  const out = [];
+  let nn = 0;
+  for (let r = 0; r < rows; r++) {
+    const yTop = bb.maxLat - r * dLat;
+    const yBot = bb.maxLat - (r + 1) * dLat;
+    for (let c = 0; c < cols; c++) {
+      const xLeft = bb.minLon + c * dLon;
+      const xRight = bb.minLon + (c + 1) * dLon;
+      // One region per cell: clip every sub-ring, keep the pieces that clear
+      // the sliver threshold, and merge them into a single feature.
+      const cellPieces = [];
+      for (const ring of work) {
+        const clipped = clipRect(ring, [xLeft, yBot, xRight, yTop]);
+        if (clipped.length < 3) continue;
+        if (ringAreaKm2(clipped, midLat) < SLIVER_KM2) continue;
+        // splitAtAM returns pieces already in standard −180..180 space (the
+        // x > 180 half remapped), so no further per-vertex remap is needed.
+        const pieces = shifted
+          ? splitAtAM(dedupeRing(clipped)).map((pc) => dedupeRing(pc))
+          : [dedupeRing(clipped)];
+        for (const pc of pieces)
+          if (pc.length >= 3) cellPieces.push(pc.map(([lo, la]) => [r4(lo), r4(la)]));
+      }
+      if (!cellPieces.length) continue;
+      const closed = cellPieces
+        .map(dedupeRing)
+        .filter((pc) => pc.length >= 3)
+        .map(closeRing);
+      if (!closed.length) continue;
+      nn += 1;
+      const nnStr = String(nn).padStart(2, '0');
+      out.push(makeFeature(`${id}-${nnStr}`, `${name} R${nnStr}`, id, closed));
+    }
+  }
+  return out;
+}
+
+function processFeature(feature) {
+  const geom = feature.geometry;
+  const am = crossesAntimeridian(geom);
+  if (am && featureAreaKm2(feature) <= BIG_KM2) {
+    // Small antimeridian island group (Fiji, Kiribati, Tuvalu, …): one region.
+    return wholeCountryFeature(feature);
+  }
+  // Wrapping rings (Antarctica) are already in standard space as wedges — no
+  // shifting; non-wrapping antimeridian countries (Russia) are shifted.
+  const rings = subjectRings(geom);
+  const hasWrap = polygons(geom).some((p) => hasAMJump(dedupeRing(p[0])));
+  const shifted = am && !hasWrap;
+  return tileFeature(feature, rings, shifted);
+}
+
+/** Total planar area of a feature's tiling rings (same convention as tileFeature). */
+function featureAreaKm2(feature) {
+  const midLat = meanLat(feature.geometry);
+  return subjectRings(feature.geometry).reduce((s, r) => s + ringAreaKm2(r, midLat), 0);
+}
+
+// --- main ---------------------------------------------------------------------------
+
+function main() {
+  const src = readFileSync(path.join(root, 'public', 'countries.geo.json'), 'utf8');
+  const countries = JSON.parse(src);
+
+  const features = [];
+  const amSingletons = [];
+  const amTiled = [];
+  for (const f of countries.features) {
+    if (crossesAntimeridian(f.geometry)) {
+      (featureAreaKm2(f) <= BIG_KM2 ? amSingletons : amTiled).push(f.id);
+    }
+    features.push(...processFeature(f));
+  }
+  // Sorted by (parent, nn) — the processing order already guarantees this, but
+  // sort explicitly so the contract holds regardless of traversal changes.
+  features.sort((a, b) => {
+    if (a.properties.parent !== b.properties.parent)
+      return a.properties.parent < b.properties.parent ? -1 : 1;
+    return a.id.localeCompare(b.id, 'en', { numeric: true });
+  });
+
+  const out = { type: 'FeatureCollection', features };
+  const json = JSON.stringify(out);
+  writeFileSync(path.join(root, 'public', 'regions.geo.json'), json + '\n');
+
+  // --- summary ----------------------------------------------------------------------
+  const counts = new Map();
+  for (const f of features)
+    counts.set(f.properties.parent, (counts.get(f.properties.parent) ?? 0) + 1);
+  const sortedCounts = [...counts.values()].sort((a, b) => a - b);
+  const median =
+    sortedCounts.length % 2
+      ? sortedCounts[Math.floor(sortedCounts.length / 2)]
+      : (sortedCounts[sortedCounts.length / 2 - 1] + sortedCounts[sortedCounts.length / 2]) / 2;
+
+  // Max region area (planar approximation, same mid-latitude convention as the
+  // tiling: the parent country's mean latitude).
+  const midLatByParent = new Map(countries.features.map((f) => [f.id, meanLat(f.geometry)]));
+  let maxArea = 0;
+  let maxId = '';
+  for (const f of features) {
+    const midLat = midLatByParent.get(f.properties.parent);
+    let a = 0;
+    for (const poly of polygons(f.geometry)) for (const ring of poly) a += ringAreaKm2(ring, midLat);
+    if (a > maxArea) {
+      maxArea = a;
+      maxId = f.id;
+    }
+  }
+
+  console.log(`regions: ${features.length} total (${countries.features.length} countries)`);
+  console.log(`file:    public/regions.geo.json — ${(Buffer.byteLength(json + '\n') / 1024).toFixed(1)} KB`);
+  console.log(
+    `count:   min ${sortedCounts[0]} / median ${median} / max ${sortedCounts[sortedCounts.length - 1]} per country`,
+  );
+  console.log(`max region: ${maxId} ≈ ${Math.round(maxArea).toLocaleString('en-US')} km²`);
+  if (amSingletons.length) console.log(`AM → 1 region: ${amSingletons.join(', ')}`);
+  if (amTiled.length) console.log(`AM → tiled (shifted/wedges): ${amTiled.join(', ')}`);
+}
+
+main();

scripts/regions.test.ts

@@ -0,0 +1,191 @@
+/**
+ * scripts/regions.test.ts — validation for the committed `public/regions.geo.json`.
+ *
+ * Self-contained (no import of the generator): it re-implements the generator's
+ * exact planar area model so the assertions measure the same quantity the
+ * generator used to size and clip regions:
+ *
+ *   x = lon · 111.32 · cos(midLat),  y = lat · 110.574  (km)
+ *
+ * with a shoelace per outer ring, where each ring is measured at its own mean
+ * latitude. Outer rings only — the generator never emits holes (every ring is an
+ * independent piece: a separate island or a separate clipped cell fragment).
+ *
+ * It reads each file exactly once and runs in O(total vertices).
+ */
+import { readFileSync } from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { describe, expect, it } from 'vitest';
+
+const here = path.dirname(fileURLToPath(import.meta.url));
+const root = path.resolve(here, '..');
+
+// --- area model (must match scripts/generate-regions.mjs exactly) -----------------
+const KM_LON = 111.32;
+const KM_LAT = 110.574;
+const rad = (deg: number) => (deg * Math.PI) / 180;
+
+type Ring = [number, number][];
+type Geometry =
+  | { type: 'Polygon'; coordinates: Ring[] }
+  | { type: 'MultiPolygon'; coordinates: Ring[][] };
+
+function ringAreaKm2(ring: Ring, midLat: number): number {
+  const kx = KM_LON * Math.cos(rad(midLat));
+  let a = 0;
+  const n = ring.length;
+  for (let i = 0; i < n; i++) {
+    const [lon1, lat1] = ring[i];
+    const [lon2, lat2] = ring[(i + 1) % n];
+    a += lon1 * kx * (lat2 * KM_LAT) - lon2 * kx * (lat1 * KM_LAT);
+  }
+  return Math.abs(a / 2);
+}
+
+function outerRings(geom: Geometry): Ring[] {
+  if (geom.type === 'Polygon') return [geom.coordinates[0]];
+  if (geom.type === 'MultiPolygon') return geom.coordinates.map((p) => p[0]);
+  return [];
+}
+
+/** Sum of a feature's outer-ring areas, each ring at its own mean latitude. */
+function featureAreaKm2(geom: Geometry): number {
+  let total = 0;
+  for (const ring of outerRings(geom)) {
+    let lat = 0;
+    for (const [, la] of ring) lat += la;
+    total += ringAreaKm2(ring, ring.length ? lat / ring.length : 0);
+  }
+  return total;
+}
+// -------------------------------------------------------------------------------
+
+interface RegionFeature {
+  type: 'Feature';
+  id: string;
+  properties: { name: string; parent: string };
+  geometry: Geometry;
+}
+interface CountryFeature {
+  type: 'Feature';
+  id: string;
+  properties: { name: string };
+  geometry: Geometry;
+}
+interface FeatureCollection<T> {
+  type: 'FeatureCollection';
+  features: T[];
+}
+
+// Read each file exactly once.
+const regions = JSON.parse(
+  readFileSync(path.join(root, 'public', 'regions.geo.json'), 'utf8'),
+) as FeatureCollection<RegionFeature>;
+const countries = JSON.parse(
+  readFileSync(path.join(root, 'public', 'countries.geo.json'), 'utf8'),
+) as FeatureCollection<CountryFeature>;
+
+// Precompute areas once (O(total vertices)).
+const countryArea = new Map<string, number>();
+for (const c of countries.features) countryArea.set(c.id, featureAreaKm2(c.geometry));
+const regionArea = new Map<string, number>();
+for (const f of regions.features) regionArea.set(f.id, featureAreaKm2(f.geometry));
+const regionSumByParent = new Map<string, number>();
+for (const f of regions.features) {
+  regionSumByParent.set(
+    f.properties.parent,
+    (regionSumByParent.get(f.properties.parent) ?? 0) + (regionArea.get(f.id) ?? 0),
+  );
+}
+const countByParent = new Map<string, number>();
+for (const f of regions.features) {
+  countByParent.set(f.properties.parent, (countByParent.get(f.properties.parent) ?? 0) + 1);
+}
+
+describe('regions.geo.json', () => {
+  it('is a valid GeoJSON FeatureCollection', () => {
+    expect(regions.type).toBe('FeatureCollection');
+    expect(Array.isArray(regions.features)).toBe(true);
+    expect(regions.features.length).toBeGreaterThan(0);
+  });
+
+  it('every region is a well-formed feature with a valid id and a valid parent country', () => {
+    const countryIds = new Set(countries.features.map((c) => c.id));
+    const idRe = /^[A-Z]{3}-\d+$/;
+    for (const f of regions.features) {
+      expect(f.type, `${f.id ?? '?'}: not a Feature`).toBe('Feature');
+      expect(idRe.test(f.id), `${f.id ?? '?'}: bad id`).toBe(true);
+      expect(typeof f.properties?.name, `${f.id}: missing name`).toBe('string');
+      expect(f.properties.name.length, `${f.id}: empty name`).toBeGreaterThan(0);
+      expect(typeof f.properties.parent, `${f.id}: missing parent`).toBe('string');
+      expect(countryIds.has(f.properties.parent), `${f.id}: unknown parent ${f.properties.parent}`).toBe(true);
+      expect(f.properties.parent, `${f.id}: parent != ISO_A3 prefix`).toBe(f.id.slice(0, 3));
+      const g = f.geometry;
+      expect(
+        !!g && (g.type === 'Polygon' || g.type === 'MultiPolygon'),
+        `${f.id}: bad geometry type ${g?.type}`,
+      ).toBe(true);
+    }
+  });
+
+  it('gives every country 1..36 regions, and >=2 for any country > 50,000 km²', () => {
+    for (const c of countries.features) {
+      const n = countByParent.get(c.id) ?? 0;
+      expect(n, `country ${c.id} has no regions`).toBeGreaterThanOrEqual(1);
+      expect(n, `country ${c.id} has ${n} regions (> 36)`).toBeLessThanOrEqual(36);
+      if ((countryArea.get(c.id) ?? 0) > 50_000) {
+        expect(n, `large country ${c.id} should have >= 2 regions`).toBeGreaterThanOrEqual(2);
+      }
+    }
+  });
+
+  it('every region has a sane area: >= 200 km² (microstates exempt) and < 5,000,000 km²', () => {
+    let maxArea = 0;
+    let maxId = '';
+    for (const f of regions.features) {
+      const a = regionArea.get(f.id) ?? 0;
+      const parentArea = countryArea.get(f.properties.parent) ?? 0;
+      // A whole-country singleton of a sub-200 km² microstate is exempt.
+      expect(a >= 200 || parentArea < 200, `${f.id}: area ${a.toFixed(1)} km² is too small`).toBe(true);
+      expect(a < 5_000_000, `${f.id}: area ${Math.round(a).toLocaleString('en-US')} km² is absurdly large`).toBe(true);
+      if (a > maxArea) {
+        maxArea = a;
+        maxId = f.id;
+      }
+    }
+    console.log(`\n  max region area: ${maxId} ≈ ${Math.round(maxArea).toLocaleString('en-US')} km²`);
+  });
+
+  it('covers each country to within [45%, 108%] of its own area', () => {
+    // The band is a planar-approximation sanity check. The measured range is
+    // ~[64%, 105%]: Antarctica's hemispheric wedges under-fill to ~64%, and
+    // Norway's fjord-heavy, high-latitude coast over-fills to ~105.1% under the
+    // single-mid-latitude approximation. [45%, 108%] brackets that with margin
+    // while still catching a genuinely missing or doubled-up region.
+    let minRatio = Infinity;
+    let maxRatio = -Infinity;
+    let minId = '';
+    let maxId = '';
+    for (const c of countries.features) {
+      const ca = countryArea.get(c.id) ?? 0;
+      if (ca <= 0) continue;
+      const ratio = (regionSumByParent.get(c.id) ?? 0) / ca;
+      if (ratio < minRatio) {
+        minRatio = ratio;
+        minId = c.id;
+      }
+      if (ratio > maxRatio) {
+        maxRatio = ratio;
+        maxId = c.id;
+      }
+      expect(
+        ratio >= 0.45 && ratio <= 1.08,
+        `${c.id}: coverage ${(100 * ratio).toFixed(1)}% is outside [45%, 108%]`,
+      ).toBe(true);
+    }
+    console.log(
+      `\n  coverage range: min ${minId} ${(100 * minRatio).toFixed(1)}% / max ${maxId} ${(100 * maxRatio).toFixed(1)}% (band 45–108%)`,
+    );
+  });
+});

tsconfig.json

@@ -20,5 +20,5 @@
       "@/*": ["./src/*"]
     }
   },
-  "include": ["src", "server", "shared", "e2e", "vite.config.ts"]
+  "include": ["src", "server", "shared", "e2e", "scripts", "vite.config.ts"]
 }

vitest.config.ts

@@ -13,7 +13,7 @@ export default defineConfig({
   },
   test: {
     environment: 'node',
-    include: ['server/**/*.test.ts'],
+    include: ['server/**/*.test.ts', 'scripts/**/*.test.ts'],
     testTimeout: 20000,
     hookTimeout: 20000,
   },