This discussion came up in another thread and I thought I would move it here as it is something we often discuss in the context of individual maps but not as a broader question.
My view on the RPG vs. natural topography discussion is that it is unhelpful to take either to extremes and the 'pleasing result' falls somewhere in-between (as always):
On one hand, you can have a completely topograhically unbelievable world with rivers running uphill, perfectly straight coastlines etc...which is fine if that's what you want, but it's not going to look 'believable.' And if you are going to violate very obvious natural laws (like gravity) then that is going to have to be consistent (or at least explained) in the game itself.
On the other hand you can get so wound up with tectonic plate movements, climate effects, magma flows and what have you alls that you'll probably never finish your map with the phenomenal amount of calculations you will have to do. You will also be depriving yourself of the opportunity to create beautiful locations if they violate natural laws. Why not have a 300 metre high finger of rock in the middle of a plain? It's no coincidence that exotic or exaggerated landscapes contribute immensely to our enjoyment of fantasy books or RPGs. After all, it's about escapism and the unreal.
So the happy medium is in the middle. Here are the informal rules I follow:
1. The map has to be reasonably believable. RPGing is after all about suspending disbelief, so as long as the world you've created seems reasonably possible that's fine. If it's too unreal, it becomes too difficult to suspend disbelief.
2. The more an element in a map doesn't follow the laws of nature (e.g. rivers defying gravity, floating cities etc) then the more that the element will need some form of explanation - (magic, dwarven machinery, moles with telekentic powers...whatever).
3. Don't be afraid to break the rules if the result looks good. I tend to choose 'visually pleasing' over 'realistic' (although of course the less realistic something looks, the less visually pleasing it tends to be - unless it's really uber, super-cool. Sometimes you just 'know' when to break the rules.
4. The map has to fit the story or world that you have created. That might influence your colour choices, whether you want your map to look like it's been hand drawn or shaded relief. Geographical landmarks have to appear in the right place. If place x is three days' ride from place y then you should calculate roughly what the distance should be. (i.e. not 2,000 miles or just around the corner).
5. The map has to have an internal consistency. By this I mean if you are going to (say) paint your mountains in one style, use that style throughout the map (unless there's a really good reason not to). If you decide to draw very small islands, don't just do it one corner of the map, put them where all small islands might be found (again, you may have a good reason not to do this, but make sure you have a good reason and that reason is apparent to the person looking at the map). I find internal consistency is one of the hardest things to achieve. It applies to everything in your map, colour choices, scale, how your coastlines look, how your buildings look - everything. You just have to rely on your eyes and an objective sense of self criticism (something again I'm terrible at) to see where something doesn't fit. That's one of the reasons why posting maps up here and having other people look at them is so helpful.
Does anyone else have any thoughts on the subject?