I already mentionned that it would be great to be able to "de-zoom" when you have a map really detailed (for instance 1:16000): it's really hard to find your target in the map!
Since it must really hard to compute from a really detailed map a "de-zoomed" map while preserving important datas (town's name, summit's name, ...): here could be an alternative.
Imagine a user that has the a map for the whole France, and also a map for Chartreuse's park. He selects the map "France" and move quickly to the area of interest and then start zooming. As soon as the zoom reaches a point where the whole screen shows data which are completely included in the Chartreuse's park's map, then the program switches map auto-magically. I don't know if it's easily done with your current design but it would be really great! Do you think it would consume too much memory? Since you don't have to open a map to compute if the data on the screen fit in it or not, it should be ok, isn't it (I mean: you always have only one map opened at a time)?
Of course you could imagine that the program shows a pop-up which proposes you to switch, records the setting ("auto accept switching" for instance), ...
Good luck!
