readLinearRing(node, objectStack) {
    const flatCoordinates = this.readFlatCoordinatesFromNode(node, objectStack);
    if (flatCoordinates) {
      return new LinearRing(flatCoordinates, 'XYZ');
    }
  }
@param {Element} node Node.
@param {Array<*>} objectStack Object stack.
@return {LinearRing|undefined} LinearRing.