code: function addLocationMarker(terria, initSources) {
    if (defined(terria.locationMarker)) {
      const position = terria.locationMarker.entities.values[0].position.getValue();
      const positionDegrees = Ellipsoid.WGS84.cartesianToCartographic(position);
  
      initSources.push({
        locationMarker: {
          name: terria.locationMarker.entities.values[0].name,
          latitude: CesiumMath.toDegrees(positionDegrees.latitude),
          longitude: CesiumMath.toDegrees(positionDegrees.longitude)
        }
      });
    }
  }
docs: Add details of the location marker if it is set.
  @private