text: define([
          '../../Core/buildModuleUrl',
          '../../Core/createWorldTerrain',
          '../../Core/EllipsoidTerrainProvider',
          '../BaseLayerPicker/ProviderViewModel'
      ], function(
          buildModuleUrl,
          createWorldTerrain,
          EllipsoidTerrainProvider,
          ProviderViewModel) {
      'use strict';
  
      /**
       * @private
       */
      function createDefaultTerrainProviderViewModels() {
          var providerViewModels = [];
          providerViewModels.push(new ProviderViewModel({
              name : 'WGS84 Ellipsoid',
              iconUrl : buildModuleUrl('Widgets/Images/TerrainProviders/Ellipsoid.png'),
              tooltip : 'WGS84 standard ellipsoid, also known as EPSG:4326',
              category: 'Cesium ion',
              creationFunction : function() {
                  return new EllipsoidTerrainProvider();
              }
          }));
  
          providerViewModels.push(new ProviderViewModel({
              name : 'Cesium World Terrain',
              iconUrl : buildModuleUrl('Widgets/Images/TerrainProviders/CesiumWorldTerrain.png'),
              tooltip : 'High-resolution global terrain tileset curated from several datasources and hosted by Cesium ion',
              category: 'Cesium ion',
              creationFunction : function(){
                  return createWorldTerrain({
                      requestWaterMask: true,
                      requestVertexNormals: true
                  });
              }
          }));
  
          return providerViewModels;
      }
  
      return createDefaultTerrainProviderViewModels;
  });
  