The Basemap Gallery widget presents a gallery of basemaps and allows you to select one from the gallery as the basemap for your map. The basemaps presented come from a group in your ArcGIS Online organization or portal. All basemaps in the Basemap Gallery widget must have the same spatial reference.
In general, basemaps with tiling schemes that are different than that of the current basemap are excluded from the widget. If the default basemap is a dynamic layer, you can switch to either dynamic layers or ArcGIS tiled map service layers. If the default basemap is a tile layer, you can switch to either tile layers with the same tiling scheme or dynamic layers. For the best performance, it is recommended that all basemaps added to the gallery be cached (tiled) layers.
See the following list of supported and unsupported basemaps in the Basemap Gallery widget:
Unsupported basemaps
Different spatial reference
Tiled basemaps with different tiling schemes
Switch from a dynamic basemap to Bing, OSM, or WMTS
Switch from a dynamic basemap to a tiled image service basemap
WMS services
Supported basemaps
Switch between tiled basemaps
Switch between dynamic basemaps
Switch from a dynamic basemap to a tiled map service basemap
Switch from a tiled basemap to a dynamic basemap
Use the Basemap Gallery widget
Clicking the Basemap Gallery widget displays all the basemaps configured for this widget. Clicking a basemap thumbnail sets it as the active basemap for the app. Click the X in the upper-right corner of the Basemap Gallery window to close it.