Hi, I'm a linguist and hobbyist conlanger. I have a map of some empty landmasses I made in Illustrator, but I don't feel knowledgeable enough to define anything more specific than that. If I were to commission someone to fill in all the natural details (e.g. rivers, mountains, biomes), who would own the rights to what? The commissioned artist would presumably own the rights to the map itself, but would she also own the idea of island X being a lush rainforest or a mountain range on continent Y? What if I wanted to commission additional maps in the future? What if I later decide that I'd like to write a novel in this setting? What does copyright cover by default, and what options would be fair for everyone involved?