Video (created before I added shorelines and fixed graphics) Sorry for the random 4 second darkness in the beginning.
All of the maps are created in 4,000 by 4,000 pixel dimensions. Each tile is 200 by 200 which means that it's a 20 by 20 grid. After I create the basic layout of the map I use fast loops to check the shorelines of the map and then overlay them with an active I created to smooth out the edges so it looks more natural than obvious tiles. After that I add tall grass, flowers, trees, and rocks randomly around the map. So far it works great.
However the method that I use now is inefficient. It uses a bunch of fast loops which in turn makes it slow to transition between the title frame and the game frame (in iOS about 5-10 seconds.) So right now I'm editing the code to hopefully make it faster and more efficient. It's taking awhile though... but in the end it should pay off because nobody wants to wait 5-10 seconds during a game.