Use scenarios for a slippy map viewer such as OpenLayers:
- A user browses the canonical base layer only.
- The user browses a specific layer(s) that has been hardcoded into the viewer.
- The user browses some basic layer, but other available layers that are covered in the current extents are displayed in a sidebar and can be toggled on and off.
- As above, but some sort of UI allows the user to only display layers in the sidebar that match certain criteria - i.e. a slider to adjust the date range
- The layers being viewed can trigger actions in the viewer:
- Layers that are below an accuracy threshold could be overlaid with transparent red tiles to indicate to the user that it is not a reliable source for digitizing features.
- The presence of a layer which has licensing that does not allow derivative works could prevent the user from editing/creating features on it.
- Metadata about the imagery could be automatically transferred to features created upon it- i.e. tagging an OSM way with the OAM source layer ID.
Use scenarios that do not involve a webmap viewer:
- A base layer for a native mobile application. For example, using the widely popular route-me open source project for iOS.
- A base layer for an OpenGL 3D globe.