Some lovely ideas here, another of those "one day ..." projects, for my website, too !
But ... Fly in the ointment ??
If you are publishing on the web, make sure the map you are using as basis isn't copyrighted ! There are more and more firms (in Germany) making a living out of trawling the web for illegal use of copyrighted material, and then imposing fines.
Ordnance Survey, for instance, say on their web site, that you are allowed to use their maps, as long as you include a specific copright notice (for which they even give you the code to include in your website)
Bob