text: /*global define*/
  define([
          '../Core/defaultValue',
          '../Core/defined',
          '../Core/defineProperties',
          '../Core/DeveloperError',
          '../Core/Event',
          './createPropertyDescriptor'
      ], function(
          defaultValue,
          defined,
          defineProperties,
          DeveloperError,
          Event,
          createPropertyDescriptor) {
      "use strict";
  
      /**
       * An optionally time-dynamic model.
       *
       * @alias ModelGraphics
       * @constructor
       */
      var ModelGraphics = function() {
          this._show = undefined;
          this._showSubscription = undefined;
          this._scale = undefined;
          this._scaleSubscription = undefined;
          this._minimumPixelSize = undefined;
          this._minimumPixelSizeSubscription = undefined;
          this._uri = undefined;
          this._uriSubscription = undefined;
          this._definitionChanged = new Event();
      };
  
      defineProperties(ModelGraphics.prototype, {
          /**
           * Gets the event that is raised whenever a new property is assigned.
           * @memberof ModelGraphics.prototype
           *
           * @type {Event}
           * @readonly
           */
          definitionChanged : {
              get : function() {
                  return this._definitionChanged;
              }
          },
  
          /**
           * Gets or sets the boolean {@link Property} specifying the model's visibility.
           * @memberof ModelGraphics.prototype
           * @type {Property}
           */
          show : createPropertyDescriptor('show'),
          /**
           * Gets or sets the Number {@link Property} specifying the model's scale.
           * @memberof ModelGraphics.prototype
           * @type {Property}
           */
          scale : createPropertyDescriptor('scale'),
          /**
           * Gets or sets the Number {@link Property} specifying the model's approximate minimum pixel size regardless of zoom.
           * @memberof ModelGraphics.prototype
           * @type {Property}
           */
          minimumPixelSize : createPropertyDescriptor('minimumPixelSize'),
          /**
           * Gets or sets the string {@link Property} specifying the model's uri.
           * @memberof ModelGraphics.prototype
           * @type {Property}
           */
          uri : createPropertyDescriptor('uri')
      });
  
      /**
       * Duplicates a ModelGraphics instance.
       *
       * @param {ModelGraphics} [result] The object onto which to store the result.
       * @returns {ModelGraphics} The modified result parameter or a new instance if one was not provided.
       */
      ModelGraphics.prototype.clone = function(result) {
          if (!defined(result)) {
              result = new ModelGraphics();
          }
          result.show = this.show;
          result.scale = this.scale;
          result.minimumPixelSize = this.minimumPixelSize;
          result.uri = this.uri;
          return result;
      };
  
      /**
       * Assigns each unassigned property on this object to the value
       * of the same property on the provided source object.
       *
       * @param {ModelGraphics} source The object to be merged into this object.
       */
      ModelGraphics.prototype.merge = function(source) {
          //>>includeStart('debug', pragmas.debug);
          if (!defined(source)) {
              throw new DeveloperError('source is required.');
          }
          //>>includeEnd('debug');
  
          this.show = defaultValue(this.show, source.show);
          this.scale = defaultValue(this.scale, source.scale);
          this.minimumPixelSize = defaultValue(this.minimumPixelSize, source.minimumPixelSize);
          this.uri = defaultValue(this.uri, source.uri);
      };
  
      return ModelGraphics;
  });