Been out of the mapping game for a while now (too busy moving house and getting settled into my new location) and this seems like the perfect theme to draw me back.
A couple of questions regarding the theme;
* As most of the world has already been mapped, must it be remapped or can one use real-world maps for an 'underlay'? An Alternate Earth will have (mostly) the same geography as this Earth and only that which is artificial will differ.
* When can it be set? Altenrnate Past, Present or Future?