Merge branch 'main' into manjunath/hal-769-gev-ux-improve-visibility-of-the-250-km-radius-circle

# Conflicts: # scripts/format-scope.json # src/layers/awareness/policy.js # src/layers/awareness/rendering.js
2026-11-05 10:53:59 +00:00 · 2026-11-03 11:00:53 -08:00
commit 0e3b1f67cf
@@ -57,7 +57,6 @@ export const CONTEXT_RIM_HEIGHT_M = 2500;
 *  keeps the 250 km edge readable between flashes, in screenshots and for
 *  low-vision viewers. Once the pulses rest, and without pulses (reduced
 *  motion, or a scene that cannot animate), it stays on screen at full. */
-
 export const AWARENESS_RANGE_RING_STYLE = Object.freeze({
  color: 'rgba(98, 181, 255, 0.95)',
  outlineColor: 'rgba(4, 12, 16, 0.8)',
@@ -234,6 +234,41 @@ for (const [place, lat, lon] of [
  });
 }

+for (const [place, lat, lon] of [
+  ['the North Pole', 90, 0],
+  ['the South Pole', -90, 0],
+  ['1e-7° from the North Pole', 90 - 1e-7, 45],
+  ['1e-8° from the South Pole', -90 + 1e-8, -120],
+]) {
+  test(`the ring stays a full circle at ${place}`, () => {
+    const center = Cesium.Cartesian3.fromDegrees(lon, lat, 0);
+    const segments = AWARENESS_RANGE_RING_STYLE.segments;
+    const positions = awarenessRangeRingPositions(
+      center,
+      AWARENESS_RADIUS_M,
+      CONTEXT_RIM_HEIGHT_M,
+    );
+    assert.equal(positions.length, segments + 1);
+    assert.ok(
+      Cesium.Cartesian3.equalsEpsilon(positions[0], positions.at(-1), 0, 1e-6),
+      'the ring closes on itself',
+    );
+    const distinct = new Set(
+      positions
+        .slice(0, segments)
+        .map(({ x, y, z }) => [x, y, z].map((v) => v.toFixed(1)).join()),
+    );
+    assert.equal(distinct.size, segments, 'every vertex is its own point');
+    // Ordinary chords are 2π × 250 km / 128 ≈ 12.3 km long.
+    for (let i = 0; i < segments; i++) {
+      const chord = Cesium.Cartesian3.distance(positions[i], positions[i + 1]);
+      assert.ok(chord > 11_500 && chord < 13_000, `chord ${i}: ${chord} m`);
+    }
+    for (const distance of surfaceDistances(center, positions))
+      assert.ok(Math.abs(distance - AWARENESS_RADIUS_M) < 100, `${distance} m`);
+  });
+}
+
 test('the ring core and halo contrast on light and dark ground', () => {
  const core = Cesium.Color.fromCssColorString(
    AWARENESS_RANGE_RING_STYLE.color,
@@ -29,7 +29,7 @@ import {
 * A closed ring of positions `radiusM` along the surface from `groundCenter`,
 * raised to `heightM`. Each bearing steps over a sphere with the ellipsoid's
 * radius of curvature in that direction (Euler's formula), which keeps the
- * ring within a few metres of the true geodesic radius at 250 km.
+ * ring within ~50 m of the true geodesic radius at 250 km.
 * @param {Cesium.Cartesian3} groundCenter Ring centre on the ellipsoid.
 * @param {number} radiusM Surface radius in metres.
 * @param {number} heightM Height of the ring above the ellipsoid.
@@ -48,31 +48,32 @@ export function awarenessRangeRingPositions(
  const e2 = 1 - (b * b) / (a * a);
  const sinLat = Math.sin(latitude);
  const cosLat = Math.cos(latitude);
+  const sinLon = Math.sin(longitude);
+  const cosLon = Math.cos(longitude);
  const w = 1 - e2 * sinLat * sinLat;
  const meridional = (a * (1 - e2)) / (w * Math.sqrt(w));
  const primeVertical = a / Math.sqrt(w);
-  const positions = new Array(segments + 1);
+  // Step along the great circle in 3D from the centre's up, north and east
+  // unit vectors. Unlike the latitude/longitude destination formula, this
+  // stays well conditioned at and next to the poles.
+  const up = [cosLat * cosLon, cosLat * sinLon, sinLat];
+  const north = [-sinLat * cosLon, -sinLat * sinLon, cosLat];
+  const east = [-sinLon, cosLon, 0];
+  const positions = [];
  for (let i = 0; i <= segments; i++) {
    const bearing = ((i % segments) / segments) * Cesium.Math.TWO_PI;
    const cosB = Math.cos(bearing);
    const sinB = Math.sin(bearing);
    const angular =
      radiusM * ((cosB * cosB) / meridional + (sinB * sinB) / primeVertical);
-    const lat = Math.asin(
-      sinLat * Math.cos(angular) + cosLat * Math.sin(angular) * cosB,
-    );
-    const lon =
-      longitude +
-      Math.atan2(
-        sinB * Math.sin(angular) * cosLat,
-        Math.cos(angular) - sinLat * Math.sin(lat),
-      );
-    positions[i] = Cesium.Cartesian3.fromRadians(
-      lon,
-      lat,
-      heightM,
-      Cesium.Ellipsoid.WGS84,
+    const cosA = Math.cos(angular);
+    const sinA = Math.sin(angular);
+    const [x, y, z] = up.map(
+      (u, k) => u * cosA + (north[k] * cosB + east[k] * sinB) * sinA,
    );
+    const lat = Math.atan2(z, Math.hypot(x, y));
+    const lon = Math.atan2(y, x);
+    positions.push(Cesium.Cartesian3.fromRadians(lon, lat, heightM));
  }
  return positions;
 }
@@ -28,6 +28,29 @@ function services() {
  };
 }

+// The application's own scene services, as src/app/layers/militaryFlights.js
+// composes them; only the surface samplers and registry are stubbed.
+async function sceneServices() {
+  return {
+    picking: await import('../../data/pickRegistry.js'),
+    sprites: await import('../../data/spriteOrder.js'),
+    trails: await import('../../data/trailRenderer.js'),
+    aircraftPresentation: await import('../../data/tr3bRegistry.js'),
+    camera: await import('../../data/trackedCamera.js'),
+    labels: await import('../../data/detectionDraw.js'),
+    geoid: await import('../../data/geoid.js'),
+    focus: await import('../../data/focusDeemphasis.js'),
+    readout: await import('../../data/trackedReadout.js'),
+    context: await import('../../data/contextStore.js'),
+    render: await import('../../renderGovernor.js'),
+    recession: await import('../../data/aircraftRecession.js'),
+    groundFloor: await import('../../data/groundFloor.js'),
+    groundSnap: await import('../../data/groundSnap.js'),
+    meshFloor: { sampleMeshFloorCells: () => {} },
+    militaryRegistry: { registerMilitaryIcaos: () => {} },
+  };
+}
+
 test('military layer instances isolate policy and restoration state without requesting a source', async () => {
  let requests = 0;
  const source = {
@@ -122,26 +145,7 @@ test('a newly seen military contact appears at its delayed position, not ahead o
  // the next fleet tick jumped it back.
  const Cesium = await import('cesium');
  const { RENDER_DELAY_SEC } = await import('./policy.js');
-  // The application's own scene services, as src/app/layers/militaryFlights.js
-  // composes them; only the surface samplers and registry are stubbed.
-  const supplied = {
-    picking: await import('../../data/pickRegistry.js'),
-    sprites: await import('../../data/spriteOrder.js'),
-    trails: await import('../../data/trailRenderer.js'),
-    aircraftPresentation: await import('../../data/tr3bRegistry.js'),
-    camera: await import('../../data/trackedCamera.js'),
-    labels: await import('../../data/detectionDraw.js'),
-    geoid: await import('../../data/geoid.js'),
-    focus: await import('../../data/focusDeemphasis.js'),
-    readout: await import('../../data/trackedReadout.js'),
-    context: await import('../../data/contextStore.js'),
-    render: await import('../../renderGovernor.js'),
-    recession: await import('../../data/aircraftRecession.js'),
-    groundFloor: await import('../../data/groundFloor.js'),
-    groundSnap: await import('../../data/groundSnap.js'),
-    meshFloor: { sampleMeshFloorCells: () => {} },
-    militaryRegistry: { registerMilitaryIcaos: () => {} },
-  };
+  const supplied = await sceneServices();
  const fixLon = -97.6;
  const fixLat = 30.3;
  const speedMps = 200;
@@ -213,6 +217,55 @@ test('a newly seen military contact appears at its delayed position, not ahead o
  );
 });

+test('a vanished military contact fades while position-less rows keep theirs', async () => {
+  // About a third of a live adsb.lol /v2/mil fetch is contacts without a
+  // position. Those rows marked every snapshot partial, so an aircraft that
+  // left the feed stayed at full opacity for five minutes.
+  const Cesium = await import('cesium');
+  const { readsbSnapshot } = await import('../../sources/live/aircraft.js');
+  const nowMs = Date.now();
+  const row = (hex, lon) => ({
+    hex,
+    lat: 30.3,
+    lon,
+    alt_baro: 20_000,
+    gs: 300,
+    track: 90,
+    seen_pos: 1,
+  });
+  const polls = [
+    [row('ae0001', -97.6), row('ae0002', -96.6), row('ae0003', -95.6)],
+    [row('ae0001', -97.5), { hex: 'ae0003' }],
+  ];
+  // Every poll also lists a contact that never has a position.
+  for (const poll of polls) poll.push({ hex: 'ae0009', type: 'mode_s' });
+  const layer = createMilitaryFlightLayer({
+    services: await sceneServices(),
+    source: {
+      label: 'Fixture aircraft',
+      getSnapshot: async () =>
+        readsbSnapshot(
+          { ac: polls.shift() },
+          { observedAtMs: nowMs, now: nowMs },
+        ),
+    },
+  });
+  const viewer = { camera: { positionCartographic: null }, scene: {} };
+  layer.testing._setTrackedMilitaryRefreshStateForTest({
+    icao24: 'seed00',
+    entity: null,
+    meta: { rawLat: 0, rawLon: 0, onGround: false },
+    billboard: { show: false, position: Cesium.Cartesian3.fromDegrees(0, 0) },
+    billboardCollection: { show: true, add: (options) => ({ ...options }) },
+    viewer,
+    tracked: false,
+  });
+  await layer.update(viewer);
+  await layer.update(viewer);
+  assert.equal(layer.findByQuery('ae0002')?.stale, true, 'vanished: fading');
+  assert.equal(layer.findByQuery('ae0003')?.stale, false, 'still listed');
+});
+
 test('voice context reads a track that rounds to north as 0°, not 360°', () => {
  const stubs = services();
  stubs.aircraftPresentation = { tr3bTypeLabel: (id, type) => type };
@@ -187,9 +187,12 @@ export class MilitaryFlightRecords {
      fixEpochMs: aircraft.positionTimeMs ?? observedAtMs,
    };
  }
-  absence(id, { complete, likelyLanded }) {
+  absence(id, { complete, retainIds, likelyLanded }) {
+    // Partial admissions and position-less rows do not prove absence, but
+    // retention remains bounded; a likely-landed position-less contact
+    // still takes the landed limit.
    if (
-      !complete &&
+      (!complete || (retainIds?.has(id) && !likelyLanded)) &&
      Date.now() - (this.data.get(id)?.observedReceiptMs ?? 0) < 300000
    )
      return 'retain';
@@ -99,6 +99,30 @@ test('military records keep bounded partial retention and release metadata only
  );
 });

+test('complete military snapshots age out vanished aircraft and retain position-less ones unless landed', () => {
+  const records = store();
+  for (const id of ['aaa001', 'aaa002', 'aaa003'])
+    records.receive(observation({ id, reference: id }), context());
+  // aaa001 and aaa003 are still listed without a position; aaa002 vanished.
+  const absent = (id, likelyLanded = false) =>
+    records.absence(id, {
+      complete: true,
+      retainIds: new Set(['aaa001', 'aaa003']),
+      likelyLanded,
+    });
+  assert.deepEqual(
+    [absent('aaa002'), absent('aaa002'), absent('aaa002')],
+    ['stale', 'stale', 'remove'],
+  );
+  assert.equal(absent('aaa001'), 'retain');
+  assert.equal(records.missingPolls.has('aaa001'), false);
+  // A landed contact that lost its position takes the landed fast-cull.
+  assert.equal(absent('aaa003', true), 'remove');
+  // Position-less retention stays bounded like partial admission.
+  records.data.get('aaa001').observedReceiptMs = Date.now() - 300001;
+  assert.equal(absent('aaa001'), 'stale');
+});
+
 test('military emergency status follows the latest poll instead of sticking', () => {
  const records = store();
  const first = records.receive(
@@ -259,6 +259,7 @@ export function createMilitarySnapshotRenderer({
      if (currentIcaos.has(icao24)) continue;
      const absence = records.absence(icao24, {
        complete: snapshot.complete,
+        retainIds: snapshot.retainIds,
        likelyLanded: queries._likelyLanded(icao24),
      });
      if (absence === 'retain') continue;
@@ -0,0 +1,184 @@
+import * as Cesium from 'cesium';
+import { msg } from '../../i18n/marker.js';
+import { OSM_PLACES_LAYER_ID } from './model.js';
+import { createNominatimStatus } from '../../sources/nominatimStatus.js';
+export * from './model.js';
+
+const OVERLAY_SOURCE_ID = OSM_PLACES_LAYER_ID;
+/** Named results that get a map label; the rest are points. */
+const LABEL_LIMIT = 48;
+const COLOR = '#7fe3ff';
+
+/**
+ * OSM Places: the results of the last voice OpenStreetMap search ("hospitals
+ * in Kathmandu"), drawn as points with name labels and queryable by
+ * analyst_query. It fetches nothing itself; `setResults` replaces the set.
+ * The search runs only on an operator-configured Overpass, so without one
+ * the layer stays empty. Session-only: never in share links or stored layer
+ * state.
+ * @param {{overlayHost: object, overpassConfigured?: () => Promise<boolean|null>}} options
+ */
+export function createOsmPlacesLayer({
+  overlayHost,
+  // The same once-per-page capability probe as Nominatim's, on Overpass.
+  overpassConfigured = createNominatimStatus({ url: '/api/overpass/status' }),
+} = {}) {
+  if (!overlayHost) throw new TypeError('OSM Places requires an overlay host');
+  let viewer = null;
+  let dataSource = null;
+  let enabled = false;
+  let records = [];
+  let meta = null;
+  let lastUpdate = null;
+  /** true / false from the server's probe, null while unknown. */
+  let configured = null;
+
+  function render() {
+    if (!dataSource) return;
+    dataSource.entities.removeAll();
+    const color = Cesium.Color.fromCssColorString(COLOR);
+    const overlay = [];
+    for (const record of records) {
+      const position = Cesium.Cartesian3.fromDegrees(record.lon, record.lat);
+      dataSource.entities.add({
+        id: `osm-place:${record.id}`,
+        position,
+        point: {
+          pixelSize: 9,
+          color,
+          outlineColor: Cesium.Color.BLACK.withAlpha(0.8),
+          outlineWidth: 2,
+          heightReference: Cesium.HeightReference.CLAMP_TO_GROUND,
+          // On top only up close (as bikeshare stations): beyond that the
+          // depth test keeps far-side points from showing through the globe.
+          disableDepthTestDistance: 2500,
+        },
+      });
+      if (record.name && overlay.length < LABEL_LIMIT)
+        overlay.push({
+          id: record.id,
+          position,
+          variant: 'label',
+          title: record.name.slice(0, 40),
+          accent: COLOR,
+          priority: LABEL_LIMIT - overlay.length,
+          collisionGroup: 'ambient-label',
+          paintLane: 'ambient-label',
+          interactive: false,
+          edgeFade: 'keyhole',
+          horizonCull: true,
+          terrainOcclusion: false,
+          gapPx: 12,
+          verticalOnly: true,
+          placement: 'above',
+        });
+    }
+    if (enabled)
+      overlayHost.setEntries(OVERLAY_SOURCE_ID, overlay, {
+        cohortLimit: LABEL_LIMIT,
+        collisionCapacity: LABEL_LIMIT,
+        moving: false,
+      });
+  }
+
+  return {
+    id: OSM_PLACES_LAYER_ID,
+    name: 'OSM Places',
+    icon: '⌖',
+    source: 'OpenStreetMap',
+    updateInterval: 0,
+
+    /** Unavailable only once the server says no Overpass is configured. */
+    getSourceAvailability() {
+      return configured === false
+        ? {
+            available: false,
+            source: OSM_PLACES_LAYER_ID,
+            reason: 'Needs an operator-configured Overpass server',
+          }
+        : { available: true, source: OSM_PLACES_LAYER_ID, reason: null };
+    },
+
+    init(nextViewer) {
+      viewer = nextViewer;
+      Promise.resolve(overpassConfigured?.())
+        .then((answer) => {
+          if (typeof answer === 'boolean') configured = answer;
+        })
+        .catch(() => {});
+      dataSource = new Cesium.CustomDataSource(OSM_PLACES_LAYER_ID);
+      dataSource.show = false;
+      viewer.dataSources.add(dataSource);
+      overlayHost.setVisible(OVERLAY_SOURCE_ID, false);
+    },
+
+    enable() {
+      enabled = true;
+      if (dataSource) dataSource.show = true;
+      overlayHost.setVisible(OVERLAY_SOURCE_ID, true);
+      render();
+      return true;
+    },
+
+    disable() {
+      enabled = false;
+      if (dataSource) dataSource.show = false;
+      overlayHost.clearSource(OVERLAY_SOURCE_ID);
+      overlayHost.setVisible(OVERLAY_SOURCE_ID, false);
+      return true;
+    },
+
+    /** Nothing to poll: results change only through setResults. */
+    async update() {
+      return true;
+    },
+
+    destroy() {
+      enabled = false;
+      overlayHost.clearSource(OVERLAY_SOURCE_ID);
+      overlayHost.setVisible(OVERLAY_SOURCE_ID, false);
+      if (dataSource && viewer) viewer.dataSources.remove(dataSource, true);
+      dataSource = null;
+      viewer = null;
+      records = [];
+      meta = null;
+      lastUpdate = null;
+    },
+
+    /**
+     * Replace the result set.
+     * @param {object[]} next Records from `mapOsmFeature`.
+     * @param {{kind: string, label: string, area: string}} nextMeta
+     */
+    setResults(next, nextMeta) {
+      records = Array.isArray(next) ? next.slice() : [];
+      meta = nextMeta ? { ...nextMeta } : null;
+      lastUpdate = Date.now();
+      render();
+    },
+
+    /** The current search, for panels and voice. */
+    getResultsMeta() {
+      return meta ? { ...meta, count: records.length } : null;
+    },
+
+    getAnalystRecords(maxCount = 2000) {
+      if (!enabled) return [];
+      const limit = Number.isFinite(maxCount)
+        ? Math.max(1, Math.floor(maxCount))
+        : 2000;
+      return records.slice(0, limit).map((record) => ({ ...record }));
+    },
+
+    getStats() {
+      return {
+        count: records.length,
+        lastUpdate,
+        error: null,
+        statusMessage: meta
+          ? `${meta.label} · ${meta.area}`
+          : msg('Voice place search (needs an Overpass server)'),
+      };
+    },
+  };
+}
@@ -0,0 +1,152 @@
+// OSM Places holds the last voice search's results: queryable while shown,
+// labelled through the overlay host, and nothing when switched off.
+//
+// Run with: npm test
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { createOsmPlacesLayer } from './index.js';
+
+function fakeOverlayHost() {
+  const calls = [];
+  return {
+    calls,
+    setEntries: (...args) => calls.push(['setEntries', ...args]),
+    clearSource: (...args) => calls.push(['clearSource', ...args]),
+    setVisible: (...args) => calls.push(['setVisible', ...args]),
+  };
+}
+
+const RECORDS = [
+  {
+    id: 'node/1',
+    lat: 27.7,
+    lon: 85.3,
+    name: 'Bir Hospital',
+    kind: 'hospital',
+  },
+  { id: 'node/2', lat: 27.71, lon: 85.31, name: null, kind: 'hospital' },
+];
+
+test('results are queryable only while the layer is on, and labels follow names', () => {
+  const host = fakeOverlayHost();
+  const layer = createOsmPlacesLayer({ overlayHost: host });
+  layer.setResults(RECORDS, {
+    kind: 'hospital',
+    label: 'hospitals',
+    area: 'Kathmandu',
+  });
+  assert.deepEqual(layer.getAnalystRecords(), [], 'off: nothing to count');
+  assert.equal(layer.getStats().count, 2);
+  assert.equal(layer.getStats().statusMessage, 'hospitals · Kathmandu');
+  layer.enable();
+  const records = layer.getAnalystRecords();
+  assert.equal(records.length, 2);
+  records[0].name = 'changed';
+  assert.equal(
+    layer.getAnalystRecords()[0].name,
+    'Bir Hospital',
+    'callers get copies',
+  );
+  assert.deepEqual(layer.getResultsMeta(), {
+    kind: 'hospital',
+    label: 'hospitals',
+    area: 'Kathmandu',
+    count: 2,
+  });
+  layer.disable();
+  assert.ok(
+    host.calls.some(
+      ([name, id]) => name === 'clearSource' && id === 'osm-places',
+    ),
+  );
+});
+
+test('an empty layer tells the operator how to fill it', () => {
+  const layer = createOsmPlacesLayer({ overlayHost: fakeOverlayHost() });
+  assert.match(layer.getStats().statusMessage, /needs an Overpass server/);
+  assert.throws(() => createOsmPlacesLayer(), TypeError);
+});
+
+test('destroy and re-init expose a fresh empty session', () => {
+  const host = fakeOverlayHost();
+  const layer = createOsmPlacesLayer({ overlayHost: host });
+  layer.setResults(RECORDS, {
+    kind: 'hospital',
+    label: 'hospitals',
+    area: 'Kathmandu',
+  });
+  assert.ok(layer.getStats().lastUpdate);
+  layer.destroy();
+  const dataSources = {
+    added: [],
+    removed: [],
+    add(source) {
+      this.added.push(source);
+      return source;
+    },
+    remove(source, destroy) {
+      this.removed.push([source, destroy]);
+      return true;
+    },
+  };
+  layer.init({ dataSources });
+  layer.enable();
+  assert.equal(layer.getResultsMeta(), null);
+  assert.deepEqual(layer.getAnalystRecords(), []);
+  assert.deepEqual(layer.getStats(), {
+    count: 0,
+    lastUpdate: null,
+    error: null,
+    statusMessage: 'Voice place search (needs an Overpass server)',
+  });
+});
+
+test('without an operator Overpass the layer shows as unavailable', async () => {
+  const added = [];
+  const viewer = { dataSources: { add: (ds) => added.push(ds), remove() {} } };
+  const off = createOsmPlacesLayer({
+    overlayHost: fakeOverlayHost(),
+    overpassConfigured: async () => false,
+  });
+  assert.equal(
+    off.getSourceAvailability().available,
+    true,
+    'unknown until asked',
+  );
+  off.init(viewer);
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.equal(off.getSourceAvailability().available, false);
+  const unknown = createOsmPlacesLayer({
+    overlayHost: fakeOverlayHost(),
+    overpassConfigured: async () => null,
+  });
+  unknown.init(viewer);
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.equal(
+    unknown.getSourceAvailability().available,
+    true,
+    'an unknown answer keeps it listed',
+  );
+});
+
+test('places are depth-tested past close range, so they never show through the globe', () => {
+  const added = [];
+  const viewer = { dataSources: { add: (ds) => added.push(ds), remove() {} } };
+  const layer = createOsmPlacesLayer({
+    overlayHost: fakeOverlayHost(),
+    overpassConfigured: async () => true,
+  });
+  layer.init(viewer);
+  layer.enable();
+  layer.setResults(RECORDS, {
+    kind: 'hospital',
+    label: 'hospitals',
+    area: 'Kathmandu',
+  });
+  const point = added[0].entities.values[0].point;
+  const distance = point.disableDepthTestDistance.getValue();
+  assert.ok(
+    Number.isFinite(distance) && distance <= 5000,
+    `depth test off only within ${distance} m`,
+  );
+});
@@ -0,0 +1,111 @@
+/**
+ * OSM Places records: OpenStreetMap features found by a voice search,
+ * mapped to plain analyst records. Pure — no Cesium.
+ * @module layers/osmPlaces/model
+ */
+
+export const OSM_PLACES_LAYER_ID = 'osm-places';
+/** A node and a way/relation of the same name this close are one site mapped twice. */
+const SAME_SITE_M = 75;
+
+/** Longest tag value kept; OSM names are open text that reaches the model. */
+const MAX_TEXT = 120;
+
+/**
+ * A tag value as plain bounded text: control characters (newlines, tabs)
+ * become spaces; format characters (bidi overrides, zero-width spaces) are
+ * dropped, except the zero-width (non-)joiners Persian and Indic names spell
+ * with; runs of whitespace collapse, and long values are cut with an
+ * ellipsis.
+ */
+function text(value) {
+  if (typeof value !== 'string') return null;
+  const clean = value
+    .replace(/\p{Cc}+/gu, ' ')
+    .replace(/(?![\u200c\u200d])\p{Cf}/gu, '')
+    .replace(/\s+/g, ' ')
+    .trim();
+  if (!clean) return null;
+  // Cut on code points so an emoji's surrogate pair is never split.
+  const chars = Array.from(clean);
+  return chars.length <= MAX_TEXT
+    ? clean
+    : `${chars
+        .slice(0, MAX_TEXT - 1)
+        .join('')
+        .trimEnd()}…`;
+}
+
+function distanceM(a, b) {
+  const toRad = Math.PI / 180;
+  const x = (b.lon - a.lon) * toRad * Math.cos(((a.lat + b.lat) / 2) * toRad);
+  const y = (b.lat - a.lat) * toRad;
+  return Math.hypot(x, y) * 6_371_000;
+}
+
+/**
+ * One feature from `/api/osm/features` → an analyst record.
+ * @param {{id: string, lat: number, lon: number, tags?: object}} feature
+ * @param {{id: string, label: string}} preset
+ * @returns {object|null}
+ */
+export function mapOsmFeature(feature, preset) {
+  if (!Number.isFinite(feature?.lat) || !Number.isFinite(feature?.lon))
+    return null;
+  const tags = feature.tags || {};
+  const [osmType] = String(feature.id || '').split('/');
+  return {
+    id: String(feature.id),
+    lat: feature.lat,
+    lon: feature.lon,
+    name: text(tags['name:en']) || text(tags.name),
+    kind: preset.id,
+    operator: text(tags.operator) || text(tags.brand),
+    emergency: text(tags.emergency),
+    wheelchair: text(tags.wheelchair),
+    openingHours: text(tags.opening_hours),
+    city: text(tags['addr:city']),
+    osmType: ['node', 'way', 'relation'].includes(osmType) ? osmType : null,
+  };
+}
+
+/**
+ * Remove double counting without merging distinct places:
+ *
+ * - the same OSM element (identical `type/id`) is counted once;
+ * - a node and a way/relation with the same name within 75 m are one site
+ *   mapped twice (a point on the building and the building outline), and
+ *   merge;
+ * - two nodes, or two ways, are always distinct places — two neighbouring
+ *   cafés of one chain are two cafés — and never merge, whatever their names.
+ *
+ * @param {object[]} records
+ * @returns {{records: object[], merged: number}}
+ */
+export function dedupeOsmRecords(records) {
+  const kept = [];
+  const seen = new Set();
+  let merged = 0;
+  for (const record of records) {
+    if (seen.has(record.id)) {
+      merged += 1;
+      continue;
+    }
+    seen.add(record.id);
+    const name = record.name?.toLowerCase();
+    const isNode = record.osmType === 'node';
+    const sameSite =
+      name &&
+      record.osmType &&
+      kept.some(
+        (other) =>
+          other.osmType &&
+          (other.osmType === 'node') !== isNode &&
+          other.name?.toLowerCase() === name &&
+          distanceM(other, record) <= SAME_SITE_M,
+      );
+    if (sameSite) merged += 1;
+    else kept.push(record);
+  }
+  return { records: kept, merged };
+}
@@ -344,14 +344,17 @@ export function createPlayback({ state: layerState, services, parts, source }) {
    }
    if (!parts.interaction.radioPresentationAllowed())
      return Promise.resolve(false);
-    if (!layerState._selectedId) {
+    if (layerState._selectedId) {
+      // Drop a fallback left by a voice step whose playback never started.
+      layerState._playFallbackId = null;
+      layerState._playFallbackFocus = null;
+    } else {
      const ranked = parts.queries.rankedVisibleStations();
      if (!ranked.length) return Promise.resolve(false);
-      layerState._playFallbackId = ranked[1]?.id || null;
-      layerState._playFallbackFocus = false;
      parts.selection.selectRadioStation(ranked[0].id, {
        autoplay: false,
        focus: false,
+        playFallback: { id: ranked[1]?.id || null, focus: false },
      });
    }
    return playSelectedRadio({ origin });
@@ -73,6 +73,16 @@ export function createSelection({
    return { filter: layerState._filter, volume: layerState._userVolume };
  }

+  // A paused or failed stream of another station would outlive its selection.
+  function releaseStaleRadioStream(stationId) {
+    if (
+      layerState._audioStationId &&
+      layerState._audioStationId !== stationId &&
+      ['paused', 'error'].includes(layerState._audioState)
+    )
+      parts.playback.stopRadioPlayback();
+  }
+
  /** Select a station. Playback occurs only when autoplay is explicitly true. */

  function selectRadioStation(
@@ -83,11 +93,18 @@ export function createSelection({
      origin = 'programmatic',
      attemptId = null,
      cameraNavigation = null,
+      playFallback = null,
    } = {},
  ) {
    if (!parts.interaction.radioPresentationAllowed()) return false;
    const station = layerState._stationById.get(String(id));
    if (!station) return false;
+    if (!autoplay) releaseStaleRadioStream(station.id);
+    // Set after the release, which clears fallbacks.
+    if (playFallback) {
+      layerState._playFallbackId = playFallback.id;
+      layerState._playFallbackFocus = playFallback.focus;
+    }
    layerState._tuningUnavailableStationId = null;
    if (
      !parts.navigation.radioCameraNavigationOwnsSelection(
@@ -104,6 +121,7 @@ export function createSelection({
    )
      parts.tuning.endRadioTuning();
    layerState._cancelledTuningPresentationStation = null;
+    const changed = layerState._selectedId !== station.id;
    layerState._selectedId = station.id;
    const generation = ++layerState._selectionGeneration;
    const sessionGeneration = layerState._sessionGeneration;
@@ -122,6 +140,9 @@ export function createSelection({
    if (focus) parts.navigation.focusStation(station);
    parts.presentation.emitState();
    if (autoplay) void parts.playback.playSelectedRadio({ origin, attemptId });
+    // A user step to another station cancels a playback voice prepared.
+    else if (origin === 'user' && changed)
+      parts.presentation.emitPlaybackControl('select', origin);
    return true;
  }

@@ -133,6 +154,7 @@ export function createSelection({
      rotate = false,
      stationIds = null,
      autoplay = true,
+      fallback = autoplay,
      origin = 'programmatic',
    } = {},
  ) {
@@ -159,25 +181,29 @@ export function createSelection({
      current < 0
        ? 0
        : (current + (direction < 0 ? -1 : 1) + ranked.length) % ranked.length;
-    layerState._playFallbackId =
-      ranked.length > 1 ? ranked[(nextIndex + 1) % ranked.length].id : null;
+    // Voice defers playback, so its silent step keeps a fallback; silent UI steps do not.
+    const fallbackId =
+      fallback && ranked.length > 1
+        ? ranked[(nextIndex + 1) % ranked.length].id
+        : null;
    const rotationCameraState = rotate
      ? parts.navigation.radioCameraState()
      : null;
    const rotationNavigation = rotate
      ? parts.navigation.beginRadioCameraNavigation(rotationCameraState)
      : null;
-    layerState._playFallbackFocus = rotate
-      ? (fallbackStation) => {
-          parts.navigation.rotateRadioStationIntoView(
-            fallbackStation,
-            0.65,
-            rotationCameraState,
-            rotationNavigation,
-          );
-          return rotationNavigation;
-        }
-      : false;
+    const fallbackFocus =
+      fallback && rotate
+        ? (fallbackStation) => {
+            parts.navigation.rotateRadioStationIntoView(
+              fallbackStation,
+              0.65,
+              rotationCameraState,
+              rotationNavigation,
+            );
+            return rotationNavigation;
+          }
+        : false;
    const station = ranked[nextIndex];
    if (rotate)
      parts.navigation.rotateRadioStationIntoView(
@@ -191,6 +217,7 @@ export function createSelection({
      focus: false,
      origin,
      cameraNavigation: rotationNavigation,
+      playFallback: { id: fallbackId, focus: fallbackFocus },
    });
  }

@@ -217,9 +244,12 @@ export function createSelection({
      },
    );
    if (!ranked.length) return null;
-    layerState._playFallbackId = ranked[1]?.id || null;
-    layerState._playFallbackFocus = false;
-    selectRadioStation(ranked[0].id, { autoplay, focus: false, origin });
+    selectRadioStation(ranked[0].id, {
+      autoplay,
+      focus: false,
+      origin,
+      playFallback: { id: ranked[1]?.id || null, focus: false },
+    });
    return ranked[0];
  }

@@ -78,6 +78,8 @@ export function createState({ services }) {

  layerState._tuningStartStationId = null;

+  layerState._tuningResumesPlayback = false;
+
  layerState._tuningResolutionSnapshot = EMPTY_ACCEPTED_CATALOG_SNAPSHOT;

  layerState._tuningStationById = new Map();
@@ -66,6 +66,12 @@ export function createTuning({ state: layerState, services, parts, source }) {
    layerState._cancelledTuningPresentationStation = null;
    layerState._tuningStartStationId = layerState._selectedId;
    layerState._tuningPreviewId = layerState._selectedId;
+    // Like Previous/Next, the release plays only if a stream was active.
+    layerState._tuningResumesPlayback = [
+      'loading',
+      'buffering',
+      'playing',
+    ].includes(layerState._audioState);
    parts.tuningNoise.installTuningNoise();
    parts.playback.pauseRadioPlayback({ origin: 'user' });
    parts.tuningNoise.syncTuningNoiseGain();
@@ -179,7 +185,9 @@ export function createTuning({ state: layerState, services, parts, source }) {
      layerState._selectionGeneration += 1;
      parts.tuningNoise.clearRadioTuningNoise({ emit: false });
      layerState._tuningUnavailableStationId = stationId;
-      parts.presentation.emitState();
+      // The drag paused the stream; with no selection, Resume would start the
+      // nearest station. Stop also publishes the state and cancels a voice handoff.
+      parts.playback.stopRadioPlayback({ origin });
      return Object.freeze({
        ok: false,
        reason: 'station-unavailable',
@@ -187,9 +195,11 @@ export function createTuning({ state: layerState, services, parts, source }) {
        generation,
      });
    }
+    const autoplay = layerState._tuningResumesPlayback;
+    layerState._tuningResumesPlayback = false;
    layerState._tuningActive = false;
-    layerState._tuningStatic = true;
-    layerState._tuningAwaitingStationId = frozenStation.id;
+    layerState._tuningStatic = autoplay;
+    layerState._tuningAwaitingStationId = autoplay ? frozenStation.id : null;
    layerState._tuningPreviewId = null;
    layerState._tuningStartStationId = null;
    layerState._tuningUnavailableStationId = null;
@@ -204,10 +214,12 @@ export function createTuning({ state: layerState, services, parts, source }) {
    layerState._playFallbackFocus = null;
    layerState._playFallbackOrigin = 'programmatic';
    layerState._playFallbackAttemptId = null;
-    parts.tuningNoise.syncTuningNoiseGain();
+    // Muting alone would leave the noise graph running after a silent release.
+    if (autoplay) parts.tuningNoise.syncTuningNoiseGain();
+    else parts.tuningNoise.clearRadioTuningNoise({ emit: false });
    parts.presentation.emitState();
    const selected = parts.selection.selectRadioStation(frozenStation.id, {
-      autoplay: true,
+      autoplay,
      focus: false,
      origin,
      cameraNavigation,
@@ -50,6 +50,11 @@ export function createTuningNoise({
    layerState._tuningNoiseGain = null;
  }

+  function suspendTuningNoiseContext() {
+    const suspended = layerState._tuningNoiseContext?.suspend?.();
+    if (suspended?.catch) void suspended.catch(() => {});
+  }
+
  function syncTuningNoiseGain() {
    if (!layerState._tuningNoiseContext || !layerState._tuningNoiseGain) return;
    const audible = radioTuningStaticShouldPlay({
@@ -79,8 +84,21 @@ export function createTuningNoise({
    if (!AudioContextClass) return false;
    if (!layerState._tuningNoiseContext)
      layerState._tuningNoiseContext = new AudioContextClass();
-    const resumed = layerState._tuningNoiseContext.resume?.();
-    if (resumed?.catch) void resumed.catch(() => {});
+    const context = layerState._tuningNoiseContext;
+    const resumed = context.resume?.();
+    // A release before the device starts finds the context still suspended,
+    // so its suspend() is a no-op; suspend again once resume() settles.
+    if (resumed?.then)
+      void resumed.then(
+        () => {
+          if (
+            layerState._tuningNoiseContext === context &&
+            !layerState._tuningNoiseSource
+          )
+            suspendTuningNoiseContext();
+        },
+        () => {},
+      );
    if (layerState._tuningNoiseSource) return true;

    const frameCount = Math.max(
@@ -120,6 +138,7 @@ export function createTuningNoise({
    if (layerState._tuningCameraNavigation)
      parts.navigation.invalidateRadioCameraNavigation();
    layerState._tuningActive = false;
+    layerState._tuningResumesPlayback = false;
    layerState._tuningStatic = false;
    layerState._tuningAwaitingStationId = null;
    layerState._tuningPreviewId = null;
@@ -131,8 +150,7 @@ export function createTuningNoise({
    parts.rendering.updateSelectionEntity();
    syncTuningNoiseGain();
    stopTuningNoiseSource();
-    const suspended = layerState._tuningNoiseContext?.suspend?.();
-    if (suspended?.catch) void suspended.catch(() => {});
+    suspendTuningNoiseContext();
    if (emit) parts.presentation.emitState();
  }
  return {
@@ -1209,6 +1209,16 @@ export function createRecentImageryLayer({
      notify('alpha');
    },

+    /** Stop catalog/preview work owned by a cancelled voice action. */
+    cancelPendingSearch() {
+      // Without a note the emptied strip would read as "no imagery".
+      if (_searching) _notice = msg('Search cancelled');
+      cancelSearch();
+      clearPending();
+      syncRender();
+      notify();
+    },
+
    /**
     * Forget the box, the candidates, both pins, the preview and any pending
     * pick; reset opacity and split and cancel the box tool. Mode and
@@ -1385,3 +1385,13 @@ test('with SELECT BOX armed, Escape clears the preview first and the next Escape
  assert.equal(f.snap().toolActive, false);
  await tool.destroy();
 });
+
+test('a voice search cancelled mid-flight says so instead of looking empty', async () => {
+  const f = fixture();
+  f.layer.enable();
+  f.layer.setBox(BOX);
+  assert.equal(f.snap().searching, true);
+  f.layer.cancelPendingSearch();
+  assert.equal(f.snap().searching, false);
+  assert.equal(f.snap().notice, 'Search cancelled');
+});
@@ -20,6 +20,19 @@ function tileFreshness(response) {
  };
 }

+/**
+ * Clip a flow line to a box. Every piece keeps its uncut line as `line`, so
+ * pieces of one line that doubles back are never paired with each other.
+ */
+function clipFlowSegment(segment, bbox) {
+  const line = segment.line || segment;
+  return clipTileLine(segment.coords, bbox).map((coords) => ({
+    ...segment,
+    coords,
+    line,
+  }));
+}
+
 /** Own one bounded decoded flow cache; every request still passes the server tile budget. */
 export function createFlowTileSource({
  fetchImpl = (...args) => globalThis.fetch(...args),
@@ -41,12 +54,7 @@ export function createFlowTileSource({
      entry?.release();
      const segments = decodeFlowTile(bytes, z, x, y, { strict: true })
        .filter(isDrivableFlowSegment)
-        .flatMap((segment) =>
-          clipTileLine(segment.coords, tileToBBox(z, x, y)).map((coords) => ({
-            ...segment,
-            coords,
-          })),
-        );
+        .flatMap((segment) => clipFlowSegment(segment, tileToBBox(z, x, y)));
      if (mark) freshness.set(segments, mark);
      return segments;
    },
@@ -87,12 +95,9 @@ export function createFlowTileSource({
    partial = result.partial;
    const segments = bounds.coverage
      ? result.tiles.flat()
-      : result.tiles.flat().flatMap((segment) =>
-          clipTileLine(segment.coords, bounds).map((coords) => ({
-            ...segment,
-            coords,
-          })),
-        );
+      : result.tiles
+          .flat()
+          .flatMap((segment) => clipFlowSegment(segment, bounds));
    const marks = result.tiles.map((tile) => freshness.get(tile) || {});
    const times = marks
      .map((mark) => mark.fetchedAt)
@@ -35,6 +35,14 @@ const MIN_FILL_M = 40;
 * Same-class overlap keeps the full 35 m matcher radius.
 */
 const CLASS_MISMATCH_RADIUS_M = 15;
+/**
+ * Opposite-direction TomTom lines this close share one street: TomTom draws
+ * both directions of a two-way street a metre or two apart, and a divided
+ * carriageway's sides further apart.
+ */
+const PAIRED_SIDE_RADIUS_M = 5;
+/** Arc-length positions sampled along a `one_side` line for its partner. */
+const PAIRED_SIDE_SAMPLES = [0.25, 0.5, 0.75];
 const CONTROLLED_ACCESS_FLOW = new Set(['Motorway', 'International road']);
 const CONTROLLED_ACCESS_OSM = new Set(['motorway', 'trunk']);

@@ -85,20 +93,69 @@ export function isDrivableFlowSegment(segment) {
  );
 }

+/**
+ * Share of a `one_side` line's sample points (PAIRED_SIDE_SAMPLES) with an
+ * opposite-direction TomTom line beside them: TomTom draws a two-way street
+ * whose directions differ as two `one_side` lines on one centreline, while a
+ * divided carriageway's other side is further away than PAIRED_SIDE_RADIUS_M.
+ * @returns {number} Paired share in [0, 1].
+ */
+function pairedSampleShare(segment, index) {
+  const xs = [];
+  const ys = [];
+  const cum = [0];
+  for (const [lon, lat] of segment.coords) {
+    const [x, y] = index.project(lon, lat);
+    const i = xs.push(x) - 1;
+    ys.push(y);
+    if (i) cum.push(cum[i - 1] + Math.hypot(x - xs[i - 1], y - ys[i - 1]));
+  }
+  const length = cum[cum.length - 1];
+  if (!(length > 0)) return 0;
+  const line = segment.line || segment;
+  let paired = 0;
+  let i = 1;
+  for (const share of PAIRED_SIDE_SAMPLES) {
+    const target = share * length;
+    while (i < cum.length - 1 && cum[i] < target) i++;
+    const dx = xs[i] - xs[i - 1];
+    const dy = ys[i] - ys[i - 1];
+    const t = (target - cum[i - 1]) / (cum[i] - cum[i - 1] || 1);
+    const reverse = (Math.atan2(-dx, -dy) * 180) / Math.PI;
+    if (
+      index.nearest(
+        xs[i - 1] + dx * t,
+        ys[i - 1] + dy * t,
+        reverse,
+        // A line that doubles back beside itself, even clipped into pieces,
+        // is not its own pair.
+        (piece) =>
+          (piece.flow.line || piece.flow) === line ? 0 : PAIRED_SIDE_RADIUS_M,
+      ).best
+    )
+      paired++;
+  }
+  return paired / PAIRED_SIDE_SAMPLES.length;
+}
+
 /**
 * Convert decoded TomTom flow lines into road records that carry their own
 * flow. A line with `coverage: 'full'` describes both travel directions;
- * `one_side` lines describe the direction they are drawn in.
+ * `one_side` lines describe the direction they are drawn in. A `one_side`
+ * line paired with the opposite direction on the same street gets that
+ * direction's half share of dots, as a two-way road's direction does.
 * @param {Array<{coords:number[][], trafficLevel:number, roadType:string, closure:boolean, coverage?:string}>} segments
 * @returns {Array<object>} Road records (`directFlow: true`).
 */
 export function flowSegmentsToRoads(segments) {
-  return (segments || [])
-    .filter(
-      (segment) =>
-        segment?.coords?.length >= 2 && isDrivableFlowSegment(segment),
-    )
-    .map((segment) => ({
+  const drivable = (segments || []).filter(
+    (segment) => segment?.coords?.length >= 2 && isDrivableFlowSegment(segment),
+  );
+  const sides = createFlowSegmentIndex(
+    drivable.filter((segment) => segment.coverage !== 'full'),
+  );
+  return drivable.map((segment) => {
+    const road = {
      coordinates: segment.coords,
      type: FLOW_ROAD_TYPES[segment.roadType],
      drivable: true,
@@ -110,7 +167,15 @@ export function flowSegmentsToRoads(segments) {
      oneway: segment.coverage === 'full' ? 0 : 1,
      flow: { level: segment.trafficLevel, closure: segment.closure === true },
      directFlow: true,
-    }));
+    };
+    if (
+      segment.coverage !== 'full' &&
+      sides &&
+      pairedSampleShare(segment, sides) >= 0.5
+    )
+      road.densityWeight = 0.5;
+    return road;
+  });
 }

 /** Cut a projected polyline to the arc-length interval [from, to]. */
@@ -1,10 +1,12 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
+import { PbfWriter } from 'pbf';
 import {
  flowSegmentsToRoads,
  resolveRoadMode,
  selectTrafficRoads,
 } from './roadModes.js';
+import { createFlowTileSource } from './flowSource.js';
 import { createTrafficSource } from './source.js';
 import { createTrafficLayer } from './index.js';
 import {
@@ -14,6 +16,7 @@ import {
  serializeStoredLayerState,
  parseStoredLayerState,
 } from '../../data/layerState.js';
+import { tileToBBox } from '../../data/tomtomTiles.js';

 const coordinates = [
  [-97.744, 30.267],
@@ -116,6 +119,133 @@ test('a full-coverage TomTom line is two-way and covers both OSM directions', ()
  assert.equal(roads.length, 1);
  assert.equal(roads[0].directFlow, true);
 });
+test("opposite TomTom sides of one street share a two-way street's dots", () => {
+  // About 1 m and 20 m north of `coordinates`, drawn westbound.
+  const back = (dLat) => ({
+    ...flow,
+    coords: coordinates.map(([lon, lat]) => [lon, lat + dLat]).reverse(),
+  });
+  const weights = (segments) =>
+    flowSegmentsToRoads(segments).map((road) => road.densityWeight ?? 1);
+  assert.deepEqual(weights([flow, back(0.00001)]), [0.5, 0.5]);
+  assert.deepEqual(weights([flow]), [1], 'a lone side keeps the one-way share');
+  assert.deepEqual(
+    weights([flow, back(0.00018)]),
+    [1, 1],
+    'a divided carriageway keeps one-way shares',
+  );
+  assert.deepEqual(
+    weights([
+      flow,
+      {
+        ...flow,
+        coords: coordinates.map(([lon, lat]) => [lon, lat + 0.00001]),
+      },
+    ]),
+    [1, 1],
+    'same-direction lines are not a pair',
+  );
+  assert.deepEqual(
+    weights([{ ...flow, coverage: 'full' }, back(0.00001)]),
+    [1, 1],
+    'a full-coverage line is not a side, and pairs with nothing',
+  );
+});
+test('a TomTom side paired along only part of its length keeps its share', () => {
+  // Westbound partners about 1 m north, from the start of `flow` to 30% and
+  // to 60% of its length: one or two of its three sample points.
+  const partner = (toLon) => ({
+    ...flow,
+    coords: [
+      [toLon, 30.26701],
+      [-97.744, 30.26701],
+    ],
+  });
+  const weightOfFlow = (other) =>
+    flowSegmentsToRoads([flow, other])[0].densityWeight ?? 1;
+  assert.equal(weightOfFlow(partner(-97.7434)), 1);
+  assert.equal(weightOfFlow(partner(-97.7428)), 0.5);
+});
+test('a TomTom side that doubles back beside itself is not its own pair', () => {
+  // East along `coordinates`, then back west about 1 m north.
+  const hairpin = {
+    ...flow,
+    coords: [...coordinates, [-97.742, 30.26701], [-97.744, 30.26701]],
+  };
+  assert.equal(flowSegmentsToRoads([hairpin])[0].densityWeight ?? 1, 1);
+});
+/** A flow tile of one-way Major roads; each line is [x, y, x, y, ...]. */
+function flowTile(lines) {
+  const writer = new PbfWriter();
+  writer.writeMessage(3, writeFlowLayer, lines);
+  return writer.finish();
+}
+function writeFlowLayer(lines, layer) {
+  layer.writeVarintField(15, 2);
+  layer.writeStringField(1, 'Traffic flow');
+  layer.writeVarintField(5, 4096);
+  layer.writeStringField(3, 'traffic_level');
+  layer.writeMessage(4, (_, value) => value.writeDoubleField(3, 0.6), null);
+  layer.writeStringField(3, 'road_type');
+  layer.writeMessage(
+    4,
+    (_, value) => value.writeStringField(1, 'Major road'),
+    null,
+  );
+  layer.writeStringField(3, 'traffic_road_coverage');
+  layer.writeMessage(
+    4,
+    (_, value) => value.writeStringField(1, 'one_side'),
+    null,
+  );
+  for (const xy of lines) {
+    // MoveTo one point, LineTo the rest, as zigzag deltas.
+    const geometry = [9];
+    for (let i = 0; i < xy.length; i++) {
+      if (i === 2) geometry.push(2 | ((xy.length / 2 - 1) << 3));
+      const delta = xy[i] - (i < 2 ? 0 : xy[i - 2]);
+      geometry.push((delta << 1) ^ (delta >> 31));
+    }
+    layer.writeMessage(
+      2,
+      (_, feature) => {
+        feature.writeVarintField(3, 2);
+        feature.writePackedVarint(2, [0, 0, 1, 1, 2, 2]);
+        feature.writePackedVarint(4, geometry);
+      },
+      null,
+    );
+  }
+}
+test('TomTom sides clipped by their tile and the view pair only with other lines', async () => {
+  // A one-way hairpin turning in the tile buffer, its arms one tile unit
+  // (about 2 m) apart, and a separate opposite pair. The tile clip cuts the
+  // hairpin into two arms; the view clip then cuts every line again.
+  const lines = [
+    [500, 1000, 4300, 1000, 4300, 1001, 500, 1001],
+    [-200, 3000, 4300, 3000],
+    [4300, 3001, -200, 3001],
+  ];
+  const source = createFlowTileSource({
+    fetchImpl: async () => new Response(flowTile(lines)),
+  });
+  const tile = tileToBBox(12, 935, 1686);
+  const west = tile.west + (tile.east - tile.west) * 0.2;
+  const { segments } = await source.fetchFlowDetail({
+    ...tile,
+    west,
+    east: tile.east - 1e-9,
+    south: tile.south + 1e-9,
+  });
+  assert.equal(segments.length, 4);
+  assert.ok(
+    segments.every((s) => s.coords.every(([lon]) => lon >= west - 1e-10)),
+  );
+  assert.deepEqual(
+    flowSegmentsToRoads(segments).map((road) => road.densityWeight ?? 1),
+    [1, 1, 0.5, 0.5],
+  );
+});
 test('bearing and distance reject nearby crossing and separate OSM roads', () => {
  const parallel = {
    ...main,