Regarding Geographical Features?
I'm in the process of refining my world that I've been writing in for a long while now (my brief foray into a high fantasy world was short, I'm back to the world I never should have left, and I am half way through writing the first draft of a novel), as I've come to a point in my writing where more details are needed.
Geographically, for a whole continent that's supposed to be rather large (if you combined all the continents together, it would be the largest part of them, and in the center), how many rivers/mountains vs. flat grasslands vs. highlands vs. deserts and the like would seem realistic, or is that all something that's up to the author? As it is, I'm going through each "section" for the map and making a list of what should be there, and I don't want to over-burden an area with too much stuff or have it have too little >.>
If you're looking for numbers or percentages I can't help you there but I can say don't overload on things except plains...it makes drawing easier. If you wanted to be very true to earth then I'd say overload on forests, hills, and rivers but those take forever to draw. If drawing is not important, and story is, then it's all up to you...just make sure that there is more sea than land.
If the radiance of a thousand suns was to burst at once into the sky, that would be like the splendor of the Mighty One...I am become Death, the Shatterer of worlds.
-J. Robert Oppenheimer (father of the atom bomb) alluding to The Bhagavad Gita (Chapter 11, Verse 32)
My Maps ~ My Brushes ~ My Tutorials ~ My Challenge Maps
It's up to you, but... (There's always a but.)
There are basic rules to climate and hydrology. That will cover most of your questions if you want to make a realistic world. Of course, in a high fantasy setting, any of these rules could be thrown out, but if they are, you should probably find an explanation for it. Even if the explanation is 'It's magic!', knowing what magical effect is needed to explain a desert right next to a shoreline will give you a better background and a more believable world.
So... That said. Start with mountain ranges. Mountain ranges and trade winds will drive a lot of your climate and hydrology. On a realistic spherical planet, trade winds are very easy to predict. Bands of wind blowing east to west or west to east, with a slight curvature due to Coriolis effects. Mountains can be predicted as well, through plate tectonics, but that's very complicated and not many will call you on it if it's wrong. Pretty much any reasonable mountain configuration can be explained by picking the right set of plate boundaries if you really want to get into it. So, place your mountains where you like them. Once you understand the rules, you may add or remove mountains to facilitate other terrain features where you want them.
Wind blowing of an ocean onto land carries a lot of water. It's absorbed the water on it's way across the ocean, and once on land it generally drops it. There are two reasons for this. First of all, any land whatsoever is going to be higher than sea level. As air gets pushed upward, it expands due to lower air pressure. Cold air can't carry as much water as hot air, so it has to drop out. This is why the northwest area of the US gets so much rain. Mountain ranges make this even more effective, which is why the California Rockies get such nice storms.
After going over those mountains, the air has lost most of its moisture. This is why there are deserts to the east of the Rocky Mountains. No water in the air to fall out means no rain, means desert. This can also happen without mountains, if your continent is large enough. Winds that blow across flat land lose their water more gradually, but it still drops out. This makes the interior of large continents into desert even without a mountain chain.
So, temperate regions with lots of rain and deserts, what else? OK, rivers. Mountains control these, as well. Take a minute and draw an imaginary line connecting the highest points of any range of mountains or hills. Rain that falls on one side of this line will drain into a different river than rain that falls on the other side. This is the basic definition of a watershed. On a continent level, each watershed eventually drains into an ocean and will generally have one major river that combines all of the smaller tributaries that feed it. As you observe a smaller section of the map, the same process is repeated, except that smaller watersheds can drain into a river or lake instead of the ocean. Lakes will collect many smaller rivers and streams, and have a single outlet river that leads to an ocean. (There are rare exceptions... The Great Salt Lake of Utah is one of them. There is so little water coming into the lake that it evaporates before it overflows into a river. The evaporation leaves dissolved minerals behind, which is why it is a salt lake.) If your continent is old enough, all interior basins of any size will have filled and eroded a channel to escape to the ocean.
Flatlands exist for a few reasons. One common one is a large river that has existed for millions of years. Over time, erosion will bring down any hills or mountains that stand in the way of the water. Find the largest water basin on your map. Trace the route that the major river of this basin takes from its source to its delta. Now expand that route a few hundred miles in every direction. You've now got an area that is likely to be flat grassland, as this area has been eroded by the river of the years through flooding and river course changes.
Hmmm.. This has gotten very long already... I think that's enough for now.
A single supercontinent (similar to Pangea on Earth millions of years ago) has lower tectonic activity. Lower tectonic activity means fewer earthquakes, fewer volcanoes, and most importantly - fewer of the processes that contribute to mountains. This doesn't mean the area would be flat, but without large-scale collisions of plates, you're not going to get a high number of large ranges.
That said, the present-day Appalachians, which can be seen on the Eastern US and have influenced formations near Ireland and Britain suggests evidence that continuous ranges did exist on supercontinents.
From this, we might expect ranges on supercontinents to be fewer, but expansive and running lengths that we don't typically see today.
Last edited by stevensj2; 10-11-2011 at 07:31 AM.