Esri provides many useful basemaps to help you make great web maps. In addition to the nine basemaps that are available in the standard Esri basemap gallery there are other basemaps available from Esri, partners, and the community that you can browse in the Living Atlas app. Your organization may design and publish its own basemap services using ArcGIS for Desktop, and there are basemaps available from other content providers that can be used in ArcGIS web maps.
As an ArcGIS Online/Portal administrator you can organize and make available the basemaps you think your members will find useful. Here are some best practices and tips for doing that...
The basics of basemaps
There are three styles of basemap: single layer, multi-layer, and tile layer.
- Single layer - A single base layer drawn underneath all other layers.
- Multi-layer - A base layer at the bottom and one or more reference layers that are drawn on top of other server-side layers (learn more here).
- Tile layer - A single base layer in a tile layer format.
Configuring your organization's basemap gallery
When authoring a web map, the easiest way to choose a basemap is to select one from the basemap picker. The selected basemap simply replaces the current basemap.
The basemaps shown in the picker can be managed by an administrator. Just create a group and configure it as the basemap gallery for your organization by going to My Organization > Edit Settings > Map > Basemap Gallery.
There is a checkbox to easily add the Esri default basemaps to your group. You can then go back to the group to remove any of the default basemaps that you don't want in your gallery. You can also share other single-layer and multi-layer basemaps to this group (as web map items) and they will appear in the picker. If you have anonymous access enabled for your organization this new group and any basemaps you put into it must be shared with everyone if you want anonymous members to access them.
Basemaps in this gallery will appear in the picker in the arcgis.com map viewer as well as Esri Maps for Office, ArcGIS Pro, ArcMap, and other ArcGIS apps when a member is signed into your organization.
Something to be aware of, however, is that adding too many basemaps to the gallery can provide an overwhelming number of choices for members and will increase the loading time of the picker (since thumbnails for every item in the gallery must be loaded). Also, tile layer basemaps do not work with the basemap picker. So only the most popular/useful single- or multi-layer basemaps should be placed the gallery.
Other ways to provide access to basemaps
So, how can you provide members with easier access to more basemaps without overloading your basemap picker? One way is to create two additional groups**, one for basemap layers and another for basemap web maps.
The layers group is mainly for single-layer basemap services saved as layer items. These basemaps can be swapped into the current web map. Just follow the easy procedure described in this blog post on using custom basemaps selecting your basemap layers group to narrow the search.
You can also add the individual layers of multi-layer basemaps as layer items to this group. This allows base layers to be used without the corresponding reference layers and also mixing-and-matching of base and reference layers from different basemaps. If you add a reference layer in this way you will have to manually manage its position in the web map's layer list.
Tile-layer and multi-layer basemaps cannot be swapped into the current web map using the method described above. To provide access to these styles of basemap create web maps with the basemap layer(s) and put these web map items in a second group. Members can use these basemaps by opening one of the the web maps in this group and adding their own layers. When they save their web map they'll be prompted to save a copy of the web map to their account.
Spreading the word
Using groups is a good way to make available any basemaps that are useful but perhaps not important or popular enough to include in the default gallery. You can provide some detail on how to use the basemaps in each group in the group summary and/or description, and make people aware of the groups by adding them to your organization's featured groups (My Organization > Edit Settings > Groups > Featured Groups), adding a link to a search that returns your organization's basemap groups to your home page description, or broadcasting their existence via email to your members.
**The separation of layers and web maps into separate groups is simply for organization, not any functional reason, so you could put all additional basemap layers and web maps in a single group. Web maps will be filtered out automatically when searching for layers in the map viewer.