text: define([
          '../Core/freezeObject'
      ], function(
          freezeObject) {
      'use strict';
  
      // Note, these values map directly to ion asset ids.
  
      /**
       * The types of imagery provided by {@link createWorldImagery}.
       *
       * @exports IonWorldImageryStyle
       */
      var IonWorldImageryStyle = {
          /**
           * Aerial imagery.
           *
           * @type {Number}
           * @constant
           */
          AERIAL : 2,
  
          /**
           * Aerial imagery with a road overlay.
           *
           * @type {Number}
           * @constant
           */
          AERIAL_WITH_LABELS : 3,
  
          /**
           * Roads without additional imagery.
           *
           * @type {Number}
           * @constant
           */
          ROAD : 4
      };
  
      return freezeObject(IonWorldImageryStyle);
  });
  