Build the Navara weather shell without the Cesium SDK: angles from geo, the surface extent in radians

Since the weather layer stopped handing Navara the Cesium global, the shared shell read ContextLimits, Math and Rectangle from an undefined SDK and drew nothing on Navara (qa-weather-engine-switch timed out). On Navara the texture limit stays unset, as Cesium's never-created context left it.

src/layers/weather/shellRendering.js

@@ -2,6 +2,7 @@ import { acquireWeatherImage } from './infraredImage.js';
 import { imageryHostStatus } from './imageryHost.js';
 import { WEATHER_DETAIL_SIZE, WEATHER_IMAGE_SIZES } from './source.js';
 import { msg } from '../../i18n/index.js';
+import * as geo from '../../geo/index.js';
 
 /** Metres above the ellipsoid. Lower shells draw first, so lightning draws last. */
 export const WEATHER_SHELL_HEIGHTS = Object.freeze({
@@ -317,7 +318,8 @@ export function createShellSurface({
 }
 
 function fitTexture(cesium, { width, height }) {
-  const limit = cesium.ContextLimits?.maximumTextureSize;
+  // Cesium's limit once its context exists; a Navara shell has no SDK.
+  const limit = cesium?.ContextLimits?.maximumTextureSize;
   // Halve, down to 1024 px wide, on devices with a smaller texture limit.
   while (limit > 0 && width > limit && width > 1024) {
     width /= 2;
@@ -574,7 +576,7 @@ export function createWeatherShell({
   /** Recompute the window from the camera's ground footprint; returns whether it changed. */
   function computeView() {
     const rectangle = detailed ? viewRectangle() : null;
-    const degrees = cesium.Math.toDegrees;
+    const degrees = geo.math.toDegrees;
     const footprint = rectangle && {
       west: degrees(rectangle.west),
       south: degrees(rectangle.south),
@@ -688,7 +690,15 @@ export function createWeatherShell({
       viewer,
       cesium,
       height,
-      rectangle: cesium.Rectangle.fromDegrees(west, south, east, north),
+      // A Navara surface reads the four radians; Cesium gets its Rectangle.
+      rectangle: cesium
+        ? cesium.Rectangle.fromDegrees(west, south, east, north)
+        : {
+            west: geo.math.toRadians(west),
+            south: geo.math.toRadians(south),
+            east: geo.math.toRadians(east),
+            north: geo.math.toRadians(north),
+          },
       onSettled: () => commit(frame),
     });
     next.bounds = frame.bounds;

src/layers/weather/shellRendering.test.mjs

@@ -1502,3 +1502,42 @@ test('global infrared keeps one full-extent image; detail images halve for small
   });
   small.shell.clear();
 });
+
+test('a Navara shell runs without the Cesium SDK and hands its surface the extent in radians', async () => {
+  const surfaces = [];
+  const shell = createWeatherShell({
+    product: 'radar',
+    viewRectangle: () => ({ west: -1.8, south: 0.5, east: -1.6, north: 0.6 }),
+    moveEnd: { addEventListener: () => () => {} },
+    requestRender: () => {},
+    fetchImpl: async () => response(),
+    decodeImage: async () => ({
+      width: 4096,
+      height: 2048,
+      close() {},
+    }),
+    createCanvas: canvas,
+    createSurface: (options) => {
+      surfaces.push(options);
+      return {
+        setAlpha() {},
+        setImage() {},
+        setWindow() {},
+        setDetail() {},
+        setHidden() {},
+        destroy() {},
+      };
+    },
+  });
+  shell.setFrame(snapshot('radar'), '2026-11-04T12:00:00Z');
+  await flush();
+  assert.equal(surfaces.length, 1);
+  assert.equal(surfaces[0].cesium, undefined);
+  const { bounds } = snapshot('radar');
+  for (const side of ['west', 'south', 'east', 'north'])
+    assert.equal(
+      surfaces[0].rectangle[side],
+      Cesium.Math.toRadians(bounds[side]),
+    );
+  shell.clear();
+});