What are some basic points of designing a geologically realistic world?

This notes some of the more basic things to remember:

Drawing Realistic Fantasy Maps | Off the Wall

 

Hmmm...

1 - Planet large/dense enough to hold an atmosphere. I have seen many maps of fantasy 'worlds' which depicted smallish continents at best. My suggestion: minimum equatorial circumference of at least 15,000 miles.

2 - lots of water...as in at least one good sized ocean of the stuff, covering at least a fifth of the planets surface (a 'fifth' is open to debate)

3 - Plate tectonics and consequences. This is where you get mountains from. Unless really old mountains (geologically speaking), also a good place for earthquakes and volcanoes.

4 - Rough rule of thumb, not always applicable - the further inland you go, the drier it gets. Rivers become creeks. More arid over all. Real world examples: central Asia, not quite central North America.

5 - Another rough rule of thumb: coastlines are seldom straight lines, at least over a protracted distance. Instead, they're 'spikey' - lots of coves and capes.

6 - Trees (forests) need water. Lots of water. You got a big forest, there will be a lot of water tied up in it somehow: rivers, lakes, rainy weather, huge underground aquifers - something. Real world example: Oregon/Washington area. The coastal portions of these states are effectively temperate rain forests. Go a few hundred miles inland, and its effectively a desert, with trees being on the uncommon side.

 

The best advise I could give would be is watershed, you can't have rivers running up hill and away from the coasts. They tend to start somewhere high or from a spring which is moderately high and ideally they should grow with size but slow as the come to the sea as the watershed drains to them either through the ground or smaller channels. This means there should be a rough outline of high ground slowly sloping down toward the sea however you can still have High points like hills etc in that area but river don't tend to flow from waterfalls in to the sea unless it's in the tropical islands. all large rivers have their own basin or share with another.

http://www2.gre.ac.uk/__data/assets/image/0009/834660/mapsofthamesriverbasindistrict.jpg

that image might explain it better. Rivers aren't just a straight line they are like spaghetti with invisible strands and they shape the land around them promoting growth and carving through rock etc. Brooks lead to streams, streams lead to rivers or lakes, and they lead to bigger rivers or the sea/river delta. Sorry if its hard to read or you know it already, I'm on my phone haha.

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When I started world building I started from the basics. World size about that of earth, then I spent a lot of time establishing plate tectonics and doing research for the map. From there mountain ranges, plateaus, basins were next, all based off the tectonics. Then a climate map, for the single continent of the story, based off the koppen system, this required a lot of work because I had to learn about high and low pressure systems, currents, prevailing winds, and how the landmasses affect everything. This allowed me to create a rainfall map, which allowed me to place rivers and a refined climate map. At this point I had about 20 layers for the map, and at that point I still hadn't placed a single town or region.

So it depends on how real you want. It takes a lot of work to get where I'm at which are the major segments. However it adds the little details that I enjoy, like I have some trade routes that change depending on the season, due to the prevailing winds, local winds and currents.

As a starting point you need to know about tectonics, and climate, it will help you avoid impossible mountains or deserts. Even if you don't go into the detail i did it will help increase the realism. There where some places I allowed fantasy to come in creating highly unlikely geography but not impossible. It also creates problems in the story for your characters to overcome. Some on the cartographersguild.com have put together great guides if your interested.

 

Planet: relevancy to star(s) as well as the type of star(s). Basic research can be had quickly to the effect of "radiation produced by star(s) x and effects on planetary bodies". Some of that may only be theoretical.

Insofar as atmosphere that depends on your world. Nuclear disaster? Layered atmosphere? Something like Avatar with neurotoxic gasees (or something like that). Then you can consider your ecosystems.

If you read about levels of organization in biology that should be sufficient to give you a raw understanding of living organization. I think its atom molecule cell organelle tissue organ system orgsnism population community ecosystem biosphere or close thereto. Again simple research. A good way to learn is to lookup the really big parks, reserves, and conserves across the world although just what knowledge you have of the land and looking at a map may suffice. Geological precision actually requires a lot. Exposure to water and what type, soil type, position to equator, local aquifers or lava deposits, altitude, major land formations, tectonics (and insofar as water consider wind paths as with tornado and tropical storm zones...times of year for predictable storms...). In effect what is given off by the land is determined by what's in the land and around it which determines what is on it. But it is fantasy. Be fantastic.

 

Mind showing some pictures of your map?

 

Water and food are the two most important things to consider. If you look at every major human population centre, they're all built near fresh water (lake, river). The need for drinking water is paramount. Second if the need to grow, raise or hunt food. The larger the population the greater the need for farms to grow crops and raise livestock. Everything after this depends on what the population has at their disposal or deems as important. They could be land-locked or ocean fairing, artists or warriors, scientific of religious, and everything in between.
I have used a map maker at donjon; Fractal World Generator. It is a wonderful tool and the map you create can be saved to your computer and opened in Photoshop to modify it as you like.

 

As others have said, I think it depends how complicated you want to go. I know people can get pretty deep into this stuff. Personally, this:

Worldbuilding by Map

has been helping me ENORMOUSLY just lately. (!!!!)

One thing I think is really helpful about this guide is that it refers everything back to your plot, your story. (It can be easy to get carried away, with world-building! There is literally no end to how far you can take this, how deep and wide you can go )

That guide, though, covers the basics, like you asked for - how to use mountains, draw coastlines ("If your line doesn’t look like it was plotted by a drunken ant, you’re doing it wrong."); weather and climates, how to get your rivers right (!!); how to consider resources, strategy, the way humans would approach settling this world. How to take your world's political, cultural - and plot! - requirements into consideration too.

All in all, pretty good general overview (IMHO). Hope it helps :smile:

 

Didn't want to post on this thread so I posted a link in the fantasy art subforum.

I read through this, and it works of your not going for realism. One thing i didn't like was how the map was tailored to fit the story. I found it interesting to solve the problems of having to have the story work around the geography, if that makes any sense. But this is all personal taste so.

 

I couldn't agree more. I have a major conurbation in a fantasy setting and dropping it into surroundings that are simply incapable of sustaining the population and the commercial aspects of the city would raise so many inconsistencies that I am sure it would make for a poor write, and so a poor read. Also one should bear in mind logistics; major cities need access to rivers and larger bodies of water, plus good roads and it is the geography that comes first, not the roads in my view.

Obviously we're are talking about map making here, but I find it's easier to keep the mountains in mind and loop the road through them, rather than have the mountains follow the road, so to speak