Merge branch 'main' into feat/radio-country-coverage

src/data/dataCredits.js

@@ -150,6 +150,20 @@ export const DATA_CREDITS = [
     key: 'usgs',
     html: 'Earthquakes: Data courtesy of the U.S. Geological Survey',
   },
+  {
+    key: 'openseamap',
+    html:
+      'Sea marks overlay: ' +
+      '<a href="https://www.openseamap.org" target="_blank" rel="noopener">© OpenSeaMap contributors</a> (CC BY-SA 2.0) · ' +
+      'Data © OpenStreetMap contributors (ODbL)',
+  },
+  {
+    key: 'opensnowmap',
+    html:
+      'Ski pistes overlay: ' +
+      '<a href="https://www.opensnowmap.org" target="_blank" rel="noopener">© www.opensnowmap.org</a> (CC BY-SA) · ' +
+      'Data © OpenStreetMap contributors (ODbL)',
+  },
   {
     key: 'nasa-gibs',
     html:

src/data/layerState.js

@@ -666,6 +666,8 @@ export const LAYER_STATE_REGISTRY = Object.freeze([
     disposition: 'enabled+options',
     optionOwner: 'satellites',
   }),
+  Object.freeze({ id: 'sea-marks', token: '6', disposition: 'enabled-only' }),
+  Object.freeze({ id: 'ski-pistes', token: '7', disposition: 'enabled-only' }),
   Object.freeze({
     id: 'street-level',
     token: '0',

src/data/layerState.test.mjs

@@ -202,8 +202,8 @@ function encode(state) {
 
 test('production registry is exact, canonical, and rejects incomplete contracts', async () => {
   assert.equal(validateLayerStateRegistry(), true);
-  assert.equal(REGISTERED_LAYER_IDS.length, 32);
-  assert.equal(new Set(REGISTERED_LAYER_IDS).size, 32);
+  assert.equal(REGISTERED_LAYER_IDS.length, 34);
+  assert.equal(new Set(REGISTERED_LAYER_IDS).size, 34);
   assert.ok(REGISTERED_LAYER_IDS.includes('transit'));
   assert.deepEqual(REGISTERED_LAYER_IDS, [...REGISTERED_LAYER_IDS].sort());
   assert.deepEqual(LEGACY_LAYER_STATE_TOKENS, {
@@ -242,20 +242,18 @@ test('production registry is exact, canonical, and rejects incomplete contracts'
   for (const [id, token] of Object.entries(LEGACY_LAYER_STATE_TOKENS)) {
     assert.equal(LAYER_STATE_TOKEN_RESERVATIONS[id], token);
   }
-  assert.equal(nextLayerStateToken(), '6');
+  assert.equal(nextLayerStateToken(), '8');
   assert.equal(
     nextLayerStateToken({
       ...LAYER_STATE_TOKEN_RESERVATIONS,
-      alpha: '6',
-      bravo: '7',
+      alpha: '8',
+      bravo: '9',
     }),
-    '8',
+    '00',
   );
   const digitsExhausted = {
     ...LAYER_STATE_TOKEN_RESERVATIONS,
-    ...Object.fromEntries(
-      [...'6789'].map((digit) => [`prior-${digit}`, digit]),
-    ),
+    ...Object.fromEntries([...'89'].map((digit) => [`prior-${digit}`, digit])),
   };
   assert.equal(nextLayerStateToken(digitsExhausted), '00');
   assert.equal(
@@ -307,8 +305,8 @@ test('production registry is exact, canonical, and rejects incomplete contracts'
   assert.equal(
     validateLayerStateAllocations(LAYER_STATE_TOKEN_RESERVATIONS, {
       ...LAYER_STATE_TOKEN_RESERVATIONS,
-      future: '6',
-      next: '7',
+      future: '8',
+      next: '9',
     }),
     true,
   );
@@ -318,7 +316,7 @@ test('production registry is exact, canonical, and rejects incomplete contracts'
         ...LAYER_STATE_TOKEN_RESERVATIONS,
         future: '00',
       }),
-    /next free token 6/,
+    /next free token 8/,
   );
   const beforeLastDigit = { ...digitsExhausted };
   delete beforeLastDigit['prior-9'];
@@ -341,10 +339,10 @@ test('production registry is exact, canonical, and rejects incomplete contracts'
   assert.throws(
     () =>
       validateLayerStateAllocations(
-        { ...LAYER_STATE_TOKEN_RESERVATIONS, merged: '6' },
-        { ...LAYER_STATE_TOKEN_RESERVATIONS, merged: '6', competing: '6' },
+        { ...LAYER_STATE_TOKEN_RESERVATIONS, merged: '8' },
+        { ...LAYER_STATE_TOKEN_RESERVATIONS, merged: '8', competing: '8' },
       ),
-    /next free token 7/,
+    /next free token 9/,
   );
   assert.throws(
     () => validateLayerStateAllocations({ future: '00' }, { future: '01' }),

src/data/layerStateTokenLedger.test.mjs

@@ -128,7 +128,7 @@ test('reservation ledger is complete, pinned, and rejects duplicate or malformed
     { ...parseLayerStateTokenReservations(reservationRows) },
     { ...LAYER_STATE_TOKEN_RESERVATIONS },
   );
-  assert.equal(Object.keys(LAYER_STATE_TOKEN_RESERVATIONS).length, 32);
+  assert.equal(Object.keys(LAYER_STATE_TOKEN_RESERVATIONS).length, 34);
   assert.deepEqual(
     { ...LAYER_STATE_TOKEN_RESERVATIONS },
     {
@@ -137,6 +137,8 @@ test('reservation ledger is complete, pinned, and rejects duplicate or malformed
       'gnss-integrity': '3',
       'air-quality': '4',
       's2-ghostmaps': '5',
+      'sea-marks': '6',
+      'ski-pistes': '7',
     },
   );
   assert.throws(
@@ -162,9 +164,9 @@ test('reservation ledger is complete, pinned, and rejects duplicate or malformed
     /Duplicate layer-state token reservation/,
   );
   assert.equal(
-    parseLayerStateTokenReservations([...reservationRows, ['future', '6']])
+    parseLayerStateTokenReservations([...reservationRows, ['future', '8']])
       .future,
-    '6',
+    '8',
   );
   assert.throws(
     () =>
@@ -182,14 +184,14 @@ test('reservation ledger is complete, pinned, and rejects duplicate or malformed
 
 test('published retired digits and competing PRs advance the merge-time allocation', () => {
   withPublishedBase(
-    { rows: [...reservationRows, ['retired-layer', '6']] },
+    { rows: [...reservationRows, ['retired-layer', '8']] },
     (cwd) => {
       const published = readPublishedLayerStateReservations('HEAD', cwd);
-      assert.equal(nextLayerStateToken(published), '7');
+      assert.equal(nextLayerStateToken(published), '9');
       assert.equal(
         validateLayerStateAllocations(published, {
           ...published,
-          newcomer: '7',
+          newcomer: '9',
         }),
         true,
       );
@@ -197,15 +199,15 @@ test('published retired digits and competing PRs advance the merge-time allocati
         () =>
           validateLayerStateAllocations(published, {
             ...published,
-            competing: '6',
+            competing: '8',
           }),
-        /next free token 7/,
+        /next free token 9/,
       );
       assert.throws(
         () =>
           validateLayerStateAllocations(published, {
             ...LAYER_STATE_TOKEN_RESERVATIONS,
-            newcomer: '6',
+            newcomer: '8',
           }),
         /changed or removed: retired-layer/,
       );
@@ -213,8 +215,8 @@ test('published retired digits and competing PRs advance the merge-time allocati
   );
 });
 
-test('PR B manually replaces provisional 6 with 7 after PR A publishes 6', () => {
-  withPublishedBase({ rows: [...reservationRows, ['pr-a', '6']] }, (cwd) => {
+test('PR B manually replaces provisional 8 with 9 after PR A publishes 8', () => {
+  withPublishedBase({ rows: [...reservationRows, ['pr-a', '8']] }, (cwd) => {
     mkdirSync(path.join(cwd, 'scripts'));
     const fixtureChecker = path.join(
       cwd,
@@ -235,8 +237,8 @@ test('PR B manually replaces provisional 6 with 7 after PR A publishes 6', () =>
 
     writeCodecFixture(
       cwd,
-      [...reservationRows, ['pr-b', '6']],
-      [{ id: 'pr-b', token: '6' }],
+      [...reservationRows, ['pr-b', '8']],
+      [{ id: 'pr-b', token: '8' }],
     );
     const beforeRebase = runCheck();
     assert.equal(beforeRebase.status, 1);
@@ -244,10 +246,10 @@ test('PR B manually replaces provisional 6 with 7 after PR A publishes 6', () =>
 
     writeCodecFixture(
       cwd,
-      [...reservationRows, ['pr-a', '6'], ['pr-b', '6']],
+      [...reservationRows, ['pr-a', '8'], ['pr-b', '8']],
       [
-        { id: 'pr-a', token: '6' },
-        { id: 'pr-b', token: '6' },
+        { id: 'pr-a', token: '8' },
+        { id: 'pr-b', token: '8' },
       ],
     );
     const staleRebase = runCheck();
@@ -255,16 +257,16 @@ test('PR B manually replaces provisional 6 with 7 after PR A publishes 6', () =>
     assert.match(staleRebase.stderr, /Duplicate layer-state token reservation/);
 
     const published = readPublishedLayerStateReservations('HEAD', cwd);
-    assert.equal(nextLayerStateToken(published), '7');
-    const validBaselineRows = [...reservationRows, ['pr-a', '6']];
-    writeCodecFixture(cwd, validBaselineRows, [{ id: 'pr-a', token: '6' }]);
+    assert.equal(nextLayerStateToken(published), '9');
+    const validBaselineRows = [...reservationRows, ['pr-a', '8']];
+    writeCodecFixture(cwd, validBaselineRows, [{ id: 'pr-a', token: '8' }]);
     const helper = spawnSync(
       process.execPath,
       [realpathSync(fixtureNext), 'pr-b'],
       { cwd, encoding: 'utf8' },
     );
     assert.equal(helper.status, 0, helper.stderr);
-    assert.match(helper.stdout, /pr-b: 7/);
+    assert.match(helper.stdout, /pr-b: 9/);
     assert.deepEqual(
       JSON.parse(readFileSync(path.join(cwd, LEDGER_PATH), 'utf8')),
       validBaselineRows,
@@ -272,20 +274,20 @@ test('PR B manually replaces provisional 6 with 7 after PR A publishes 6', () =>
     );
     writeCodecFixture(
       cwd,
-      [...reservationRows, ['pr-a', '6'], ['pr-b', '7']],
+      [...reservationRows, ['pr-a', '8'], ['pr-b', '9']],
       [
-        { id: 'pr-a', token: '6' },
-        { id: 'pr-b', token: '7' },
+        { id: 'pr-a', token: '8' },
+        { id: 'pr-b', token: '9' },
       ],
     );
     const corrected = runCheck();
     assert.equal(corrected.status, 0, corrected.stderr);
-    assert.match(corrected.stdout, /33 published, 1 new/);
+    assert.match(corrected.stdout, /35 published, 1 new/);
   });
 });
 
 test('allocation batches cross the last digit and base-36 pair boundaries in order', () => {
-  const digitRows = [...'6789'].map((digit) => [`retired-${digit}`, digit]);
+  const digitRows = [...'89'].map((digit) => [`retired-${digit}`, digit]);
   const allDigits = parseLayerStateTokenReservations([
     ...reservationRows,
     ...digitRows,
@@ -337,7 +339,7 @@ test('allocation batches cross the last digit and base-36 pair boundaries in ord
 test('an isolated valid two-character fixture round-trips an l field beyond the old 64-character cap', async () => {
   const cwd = mkdtempSync(path.join(tmpdir(), 'gev-layer-token-width-'));
   try {
-    const priorDigits = [...'6789'].map((digit) => [
+    const priorDigits = [...'89'].map((digit) => [
       `qa-prior-digit-${digit}`,
       digit,
     ]);
@@ -374,7 +376,7 @@ test('an isolated valid two-character fixture round-trips an l field beyond the
     const params = new URLSearchParams([['v', '2']]);
     codec.encodeLayerStateParams(params, state);
     assert.ok(params.get('l').length > 64, 'fixture must cross the old cap');
-    assert.equal(params.get('l').length, 75);
+    assert.equal(params.get('l').length, 79);
     const restored = codec.decodeLayerStateParams(params);
     assert.deepEqual(restored?.enabledLayerIds, expectedLayerIds);
     assert.deepEqual(restored?.options, state.options);
@@ -392,7 +394,7 @@ test('checker reads a complete future base ledger and rejects retired-token reus
     },
     (cwd) => {
       const published = readPublishedLayerStateReservations('HEAD', cwd);
-      assert.equal(Object.keys(published).length, 33);
+      assert.equal(Object.keys(published).length, 35);
       assert.equal(published['retired-layer'], '00');
       assert.throws(
         () =>

src/data/layerStateTokenReservations.json

@@ -22,6 +22,8 @@
   ["rocket-launches", "x"],
   ["s2-ghostmaps", "5"],
   ["satellites", "s"],
+  ["sea-marks", "6"],
+  ["ski-pistes", "7"],
   ["street-level", "0"],
   ["telegeography-submarine-cables", "u"],
   ["traffic", "t"],

src/data/osmOverlays.js

@@ -0,0 +1,190 @@
+import * as Cesium from 'cesium';
+import { NO_IMAGERY_HOST, resolveImageryHost } from '../maps/imageryHost.js';
+
+/**
+ * @file Open-data raster overlays: OpenSeaMap sea marks and OpenSnowMap ski
+ * pistes (#10). Each overlay is its own layer with its own row under
+ * Infrastructure; both are built from the descriptors below.
+ *
+ * OpenRailwayMap and OpenInfraMap, also named in #10, are deliberately not
+ * included:
+ *  - OpenRailwayMap's public tile server (tiles.openrailwaymap.org) only
+ *    serves requests whose Referer is openrailwaymap.org; every other Referer,
+ *    including none, gets 403. A tab on this app sends its own origin, so the
+ *    tiles would fail, and embedding them would run against their tile-usage
+ *    policy either way.
+ *  - OpenInfraMap serves MapLibre vector tiles, not raster XYZ tiles. That
+ *    needs a vector-tile rendering pipeline, not an imagery-layer drop-in.
+ *
+ * The overlays drape on whatever surface the active map stack offers (see
+ * `maps/imageryHost.js`): the globe on the OSM and Bing stacks, the Google
+ * Photorealistic tileset's own `imageryLayers` on Google 3D. Only a stack with
+ * neither leaves them hidden, and the row says so.
+ * @module data/osmOverlays
+ */
+
+/** @type {ReadonlyArray<{id:string,name:string,icon:string,source:string,urlTemplate:string,credit:string,maximumLevel:number}>} */
+export const OSM_OVERLAYS = Object.freeze([
+  Object.freeze({
+    id: 'sea-marks',
+    name: 'Sea Marks',
+    icon: '⚓',
+    source: 'OpenSeaMap',
+    urlTemplate: 'https://tiles.openseamap.org/seamark/{z}/{x}/{y}.png',
+    // Chart tiles CC BY-SA 2.0; the underlying data is OpenStreetMap (ODbL).
+    credit:
+      'Sea marks © OpenSeaMap contributors (CC BY-SA 2.0) · Data © OpenStreetMap contributors (ODbL)',
+    maximumLevel: 18,
+  }),
+  Object.freeze({
+    id: 'ski-pistes',
+    name: 'Ski Pistes',
+    icon: '⛷',
+    source: 'OpenSnowMap',
+    urlTemplate: 'https://www.opensnowmap.org/pistes/{z}/{x}/{y}.png',
+    // OpenSnowMap asks for "(c)www.opensnowmap.org" wherever its tiles appear.
+    credit:
+      'Ski pistes © www.opensnowmap.org (CC BY-SA) · Data © OpenStreetMap contributors (ODbL)',
+    maximumLevel: 18,
+  }),
+]);
+
+/** Why an enabled overlay is showing nothing, or null. */
+export function osmOverlayHiddenReason(enabled, hostKind) {
+  return enabled && hostKind === 'none' ? NO_IMAGERY_HOST : null;
+}
+
+/**
+ * Create the layer for one overlay descriptor. Each application catalog gets
+ * its own instances; the Cesium factories are injectable so tests run without
+ * WebGL.
+ */
+export function createOsmOverlayLayer(
+  overlay,
+  {
+    host = resolveImageryHost,
+    createProvider = (descriptor) =>
+      new Cesium.UrlTemplateImageryProvider({
+        url: descriptor.urlTemplate,
+        credit: descriptor.credit,
+        maximumLevel: descriptor.maximumLevel,
+      }),
+    createImageryLayer = (provider) => new Cesium.ImageryLayer(provider),
+  } = {},
+) {
+  if (!OSM_OVERLAYS.includes(overlay))
+    throw new TypeError(`Unknown open map overlay: ${overlay?.id}`);
+  let viewer = null;
+  let mapStack = null;
+  let unsubscribeMap = null;
+  let enabled = false;
+  let hostInfo = { collection: null, kind: 'none' };
+  /** The imagery layer this instance owns while enabled, and where it sits. */
+  let owned = null;
+
+  const usable = (collection) => collection && !collection.isDestroyed?.();
+
+  function detach(destroy) {
+    if (!owned) return;
+    const { collection, layer } = owned;
+    if (usable(collection) && collection.contains(layer))
+      collection.remove(layer, destroy);
+    else if (destroy && !layer.isDestroyed?.()) layer.destroy?.();
+    owned.collection = null;
+    if (destroy) owned = null;
+  }
+
+  function resolveHost() {
+    return (
+      host({ viewer, tileset: mapStack?.getImageryHostTileset?.() }) || {
+        collection: null,
+        kind: 'none',
+      }
+    );
+  }
+
+  /** Create, move or drop the owned imagery layer to match the state. */
+  function sync() {
+    if (!viewer) return;
+    hostInfo = enabled ? resolveHost() : { collection: null, kind: 'none' };
+    if (!enabled) {
+      detach(true);
+    } else {
+      owned ||= {
+        layer: createImageryLayer(createProvider(overlay)),
+        collection: null,
+      };
+      if (owned.collection !== hostInfo.collection) {
+        detach(false);
+        if (usable(hostInfo.collection)) {
+          // Appended, so it draws above the map stack's base imagery.
+          hostInfo.collection.add(owned.layer);
+          owned.collection = hostInfo.collection;
+        }
+      }
+    }
+    viewer.scene?.requestRender?.();
+  }
+
+  return {
+    id: overlay.id,
+    name: overlay.name,
+    icon: overlay.icon,
+    source: overlay.source,
+    updateInterval: 0,
+    init(nextViewer) {
+      viewer = nextViewer;
+    },
+    /** Follow map-stack switches so the drape moves with the surface. */
+    attachMapStackController(controller) {
+      unsubscribeMap?.();
+      unsubscribeMap = null;
+      mapStack = controller || null;
+      const off = controller?.subscribe?.(() => {
+        if (enabled) sync();
+      });
+      unsubscribeMap = typeof off === 'function' ? off : null;
+    },
+    enable() {
+      enabled = true;
+      sync();
+    },
+    disable() {
+      enabled = false;
+      sync();
+    },
+    update() {
+      return true;
+    },
+    getStats() {
+      // Without a controller subscription the stats poll doubles as the
+      // map-stack watch.
+      if (enabled && !unsubscribeMap) {
+        const next = resolveHost();
+        if (next.collection !== hostInfo.collection) sync();
+      }
+      return {
+        count: enabled ? 1 : 0,
+        error: osmOverlayHiddenReason(enabled, hostInfo.kind),
+      };
+    },
+    /** Owned layer count and host kind, for tests and live gates. */
+    diagnostics() {
+      return { host: hostInfo.kind, ownedCount: owned ? 1 : 0 };
+    },
+    destroy() {
+      enabled = false;
+      detach(true);
+      unsubscribeMap?.();
+      unsubscribeMap = null;
+      mapStack = null;
+      viewer = null;
+      hostInfo = { collection: null, kind: 'none' };
+    },
+  };
+}
+
+/** One layer per overlay, in panel order. */
+export function createOsmOverlayLayers(options) {
+  return OSM_OVERLAYS.map((overlay) => createOsmOverlayLayer(overlay, options));
+}

src/data/osmOverlays.test.mjs

@@ -0,0 +1,167 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  OSM_OVERLAYS,
+  createOsmOverlayLayer,
+  createOsmOverlayLayers,
+  osmOverlayHiddenReason,
+} from './osmOverlays.js';
+import { NO_IMAGERY_HOST } from '../maps/imageryHost.js';
+
+function fakeCollection() {
+  const layers = [];
+  const removed = [];
+  return {
+    layers,
+    removed,
+    add(layer) {
+      layers.push(layer);
+    },
+    contains(layer) {
+      return layers.includes(layer);
+    },
+    remove(layer, destroy) {
+      const index = layers.indexOf(layer);
+      if (index < 0) return false;
+      layers.splice(index, 1);
+      removed.push({ layer, destroy });
+      if (destroy) layer.destroyed = true;
+      return true;
+    },
+  };
+}
+
+function fakeMapStack() {
+  const subscribers = new Set();
+  return {
+    tileset: null,
+    getImageryHostTileset() {
+      return this.tileset;
+    },
+    subscribe(fn) {
+      subscribers.add(fn);
+      return () => subscribers.delete(fn);
+    },
+    emit() {
+      for (const fn of subscribers) fn();
+    },
+    subscribers,
+  };
+}
+
+function setup(overlay = OSM_OVERLAYS[0]) {
+  const globe = fakeCollection();
+  const viewer = {
+    imageryLayers: globe,
+    scene: { globe: { show: true }, requestRender() {} },
+  };
+  const created = [];
+  const layer = createOsmOverlayLayer(overlay, {
+    createProvider: (descriptor) => ({ descriptor }),
+    createImageryLayer: (provider) => {
+      const imagery = { provider, destroyed: false };
+      created.push(imagery);
+      return imagery;
+    },
+  });
+  const mapStack = fakeMapStack();
+  layer.init(viewer);
+  layer.attachMapStackController(mapStack);
+  return { layer, viewer, globe, created, mapStack };
+}
+
+test('OSM_OVERLAYS: the two shipped layers, each with a tile template and credit', () => {
+  assert.deepEqual(
+    OSM_OVERLAYS.map((o) => o.id),
+    ['sea-marks', 'ski-pistes'],
+  );
+  for (const overlay of OSM_OVERLAYS) {
+    assert.match(overlay.urlTemplate, /^https:\/\/.*\{z\}.*\{x\}.*\{y\}/);
+    assert.match(overlay.credit, /OpenStreetMap contributors \(ODbL\)/);
+  }
+  assert.match(OSM_OVERLAYS[0].credit, /CC BY-SA 2\.0/);
+  assert.match(OSM_OVERLAYS[1].credit, /www\.opensnowmap\.org/);
+});
+
+test('createOsmOverlayLayers builds one independent layer per overlay', () => {
+  const layers = createOsmOverlayLayers();
+  assert.deepEqual(
+    layers.map((layer) => [layer.id, layer.name]),
+    [
+      ['sea-marks', 'Sea Marks'],
+      ['ski-pistes', 'Ski Pistes'],
+    ],
+  );
+  assert.notEqual(createOsmOverlayLayers()[0], layers[0]);
+  assert.throws(() => createOsmOverlayLayer({ id: 'other' }), /Unknown/);
+});
+
+test('osmOverlayHiddenReason: only when enabled with no imagery host', () => {
+  assert.equal(osmOverlayHiddenReason(false, 'none'), null);
+  assert.equal(osmOverlayHiddenReason(true, 'globe'), null);
+  assert.equal(osmOverlayHiddenReason(true, 'tileset'), null);
+  assert.equal(osmOverlayHiddenReason(true, 'none'), NO_IMAGERY_HOST);
+});
+
+test('a layer owns no imagery until enabled and destroys it on disable', () => {
+  const { layer, globe, created } = setup(OSM_OVERLAYS[1]);
+  assert.equal(created.length, 0);
+
+  layer.enable();
+  assert.equal(globe.layers.length, 1);
+  assert.equal(globe.layers[0].provider.descriptor.id, 'ski-pistes');
+  assert.deepEqual(layer.getStats(), { count: 1, error: null });
+
+  layer.disable();
+  assert.equal(globe.layers.length, 0);
+  assert.equal(created[0].destroyed, true);
+  assert.deepEqual(layer.diagnostics(), { host: 'none', ownedCount: 0 });
+  assert.deepEqual(layer.getStats(), { count: 0, error: null });
+
+  layer.enable();
+  assert.equal(created.length, 2, 're-enabling creates a fresh imagery layer');
+});
+
+test('the overlay follows a map-stack switch onto the Google 3D tileset and back', () => {
+  const { layer, viewer, globe, mapStack } = setup();
+  layer.enable();
+  const [imagery] = globe.layers;
+
+  const tileset = { imageryLayers: fakeCollection() };
+  viewer.scene.globe.show = false;
+  mapStack.tileset = tileset;
+  mapStack.emit();
+  assert.equal(globe.layers.length, 0);
+  assert.deepEqual(tileset.imageryLayers.layers, [imagery]);
+  assert.equal(globe.removed[0].destroy, false);
+  assert.equal(layer.diagnostics().host, 'tileset');
+  assert.equal(layer.getStats().error, null);
+
+  viewer.scene.globe.show = true;
+  mapStack.tileset = null;
+  mapStack.emit();
+  assert.deepEqual(globe.layers, [imagery]);
+  assert.equal(tileset.imageryLayers.layers.length, 0);
+});
+
+test('with no surface to drape on the row explains itself, and recovers when one appears', () => {
+  const { layer, viewer, globe, mapStack } = setup();
+  viewer.scene.globe.show = false;
+  layer.enable();
+  assert.equal(globe.layers.length, 0);
+  assert.equal(layer.getStats().error, NO_IMAGERY_HOST);
+
+  viewer.scene.globe.show = true;
+  mapStack.emit();
+  assert.equal(globe.layers.length, 1);
+  assert.equal(layer.getStats().error, null);
+});
+
+test('destroy removes owned imagery and unsubscribes from the map stack', () => {
+  const { layer, globe, created, mapStack } = setup();
+  layer.enable();
+  layer.destroy();
+  assert.equal(globe.layers.length, 0);
+  assert.equal(created[0].destroyed, true);
+  assert.equal(mapStack.subscribers.size, 0);
+});