There is no map editor as the maps are the carrot that brings in the customer. That being said there are six maps for Gettysburg, three for Pipe Creek, three for Antietam, and coming soon will be the three overlapping Chancellorsville maps plus the Salem Church map. There are two generic maps, Kansas and Alpine that have several surface mods released. In addition, there are map pack maps for the battles of Olustee, Secessionville, Valverde and Trevilian Station. Finally a map pack is in development for the Red River campaign (4 maps at least). So there is no shortage of places to fight and more on the way.
There is no scenario editor but the game includes by design extensive modding capabilities and an SDK that documents most of what files do what in this rather complex system. There is an entire section of the NSD forum devoted to released mods and answering questions on how to build better mods. You can create an OOB and scenario for any battle you want although most of the OOBs have been done already for SOW or have been ported in from TC2M and can just be downloaded for your fighting pleasure.
Design Lead: Scourge of War
"My God, if we've not got a cool brain and a big one too, to manage this affair, the nation is ruined forever." Unknown private, 14th Vermont Infantry, 2 July 1863