With Topo Maps+ PRO you can create custom maps by overlaying maps on top of each other.
You can access the map overlays from the overlay button and then Map Overlays.
On the Map Overlays screen you can toggle on the maps you want to use as overlays. When you toggle on a map overlay you have options for how you want the map to combine with the other maps and what level of transparency you want. Here I am combining a USGS topo map with a Satellite map.
You can also choose to add a counters only map with a custom color as an overlay.
When you turn on a map overlay you can choose how you want the map to blend with the other layers by tapping on the gear icon. Here is an example of the Glacier Topo map overlaying the USGS topo map. The first map is using Multiple for the blend mode and the second one is using Normal for the blend mode.
Here is another example, the Satellite Map is the base map with US Hill Shading and Contours Only as overlays.
Here is another example with a USGS base map and Thunderforest as an overlay.
