Ahm, thank you guys very much! I`ve already seen stunning works here!
About my process, in fact I`m still finding my way of painting, specially maps. This was my very first map, so I looked for references both traditional and realistic styles AND satellite view. My client is not an Editor or something like that, he is... my best friend. He is really into RPG games and stuff and he asked me this comission. I did all in photoshop, separating folders: forests, mountains and volcanos, castles and villages, ground, extra textures(google maps printscreen), names, icons and so on. And a little help with a big brush set I downloaded from devianart user "concept-on-mac".
I might do new and better ones, since I`m making a game concept art for my college final presentation.