Generating an Atlas where the basemap raster is the variable

Question

I have 100+ basemaps of a site throughout time (separate raster files) and I need to create a PDF figure for each basemap in QGIS 3.24.3 with a static site boundary polygon and constant print composer extent. How might I do this?

Answer 1

Create as many polygons as you have basemaps all laying on top of each other. Each feature should have some attribute that resembles one of the basemaps. Preferably in chronological order.

Then create an atlas using the polygons as atlas features. In the item properties of the map choose "lock layers" and click the icon for data defined overrides.

Here you can write a list of layers that should be visible in the map. You'll want to override this information in such a way, that it choses just the one basemap that is connected to the polygon. For example having a name field in which the name of a basemap is stored, you can just write "name" in the override.

Because the attribute changes for every atlas feature you will get a different basemap for every atlas page.