There are different maps which could be used, such as: [opencyclemap](https://www.openstreetmap.org/#map=6/40.539/-1.890&layers=Y), [StamenTerrain](http://maps.stamen.com/terrain/#12/37.7706/-122.3782), [Esri's](https://gis.stackexchange.com/questions/367189/satellite-image-in-openlayers), ... It could be nice if this map layer can be selected with an [embedded button ](https://openlayers.org/en/latest/examples/custom-controls.html)
There are different maps which could be used, such as: opencyclemap, StamenTerrain, Esri's, ...
It could be nice if this map layer can be selected with an embedded button