Campaign Cartographer 3... yes it is a very powerful program and it can help you create those worlds you want. Doing maps like you've seen in boiks is possible, mostly they are done on CC3. It is like the standard.
It does have some down sides to it.
1.- COST. It is not a cheap program... and the expansions do cost money.
2.- Learning curve... like any good ol' fashioned CAD program... it is not the easiest of critters to use.
3.- Installation.... (I already own it, from my years producing games) It can be a pain. That is a nice way to put it.
On the up side, with practice, and after a steep learning curve and yes... time... lots of it, you too can produce things like this.
And with a lot of practice and the proper expansion....
I am making a city, after two hours of installing. Athos is it's name... and I am tempted, since it is just for personal use, to reach for the damn grid paper... and a good pencil. As is doing a rough might be a good idea anyway... Still it is coming along nicely... So get some coffee and go to the gaming machine I guess.