EPSG:4479 used as geographic data: coordinates reach seven digits

• Coordinates come back as -2177350, 4389500, 4070300 when TILEMATRIXSET=4479 is requested instead of degree values.
• Cesium.Cartesian3.fromDegrees(x, y, z) with those numbers flies the camera outside the Earth and the screen goes black.
• The same request with TILEMATRIXSET=4490 works normally and returns 116.397, 39.909.

1. Count the components: three values where the third is not a plausible height means geocentric XYZ.
2. Check magnitude: geocentric coordinates all fall in the 2.0e6~6.4e6 range and stay below 6378137 plus height.
3. Re-read the service documentation for the TILEMATRIXSET or SRS parameter and confirm 4490 is intended.
4. Convert 4479 to 4490 with proj4 using an explicit geocent projection and check the result lands in China.
5. Verify the rendering call: fromDegrees takes degrees, Cartesian3 takes metres.

Request 4490 only; if geocentric values arrive, convert them with proj4('+proj=geocent +datum=WGS84', 'EPSG:4490', [x,y,z]) before any renderer sees them.

proj4.defs('EPSG:4479',
  '+proj=geocent +ellps=GRS80 +units=m +no_defs');
proj4.defs('EPSG:4490',
  '+proj=longlat +ellps=GRS80 +no_defs');

proj4('EPSG:4479', 'EPSG:4490', [-2177350, 4389500, 4070300]);
// => [116.3974, 39.9092]

const p = new Cesium.Cartesian3(-2177350, 4389500, 4070300);
viewer.camera.lookAt(p, new Cesium.Cartesian3(0, 0, 0));
// Cesium.Cartesian3.fromDegrees(116.3974, 39.9092, 50)

• Dividing the geocentric X and Y by 111320 as if they were degrees.
• Mixing Cartesian3 (metres, ECEF) with fromDegrees (degrees) in Cesium; no error is thrown, the camera just ends up elsewhere.