This sample demonstrates how to display a Basemap Gallery component to allow users to switch between different basemaps.

By default, the Basemap Gallery will display a list of basemaps from arcgis.com. If you have a portalUrl defined, then the Basemap Gallery will display a list of basemaps defined in your Portal instead. In an app with a Map component, only 2D basemaps will be shown. If Scene component is used instead, also 3D basemaps (distinguishable with a ‘3D’ tag) are included.

To update the list of basemaps displayed, set the source property of the Basemap Gallery. This can either point to a different portal source, or a local list of basemaps. See Basemaps with different projections for an example defining a PortalBasemapsSource.

To create a custom list of basemaps from local sources, source should be set to an array of basemaps representing LocalBasemapsSource. This can include basemaps created by referencing their PortalItem, or from a well known basemap ID, as shown in the following code snippet.

const customBasemap = new Basemap({
  portalItem: {
    id: "46a87c20f09e4fc48fa3c38081e0cae6",
  },
});
document.querySelector("arcgis-basemap-gallery").source = new LocalBasemapsSource({
  basemaps: [Basemap.fromId("topo-vector"), Basemap.fromId("hybrid"), customBasemap],
});