Glad you like my map.
To answer your question, Most of the time I make the map with DundJinni and then edit a little with Photoshop. DJ is an Object / Tile based program, not a drawing program. So it is more a matter of assembling all the right parts. It is not particularly good at the kind of world and regional maps that are done so well here. I really love the program, but the DJ company is not providing any support right now. The DundJinni Forums is a huge resource of art and Battlemaps. You should check it out when you have a chance. Anyone can look and download, but you need to register and then email me to get activated before you can post.
Welcome to the Guild.