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RoninFrosty
03-11-2009, 03:31 PM
I'd like the geography in my world to follow real world patterns, but I'm not really even 100% on the rules on Earth, lol. Does anyone have any resources I could use to this end?

Midgardsormr
03-11-2009, 04:18 PM
I find a good place to start to be Expeditious Retreat Press' free A Magical Society: Guide to Mapping (http://xrp.yourgamesnow.com/index.php?main_page=product_info&cPath=1&products_id=5)

Redrobes
03-11-2009, 05:43 PM
I'd like the geography in my world to follow real world patterns, but I'm not really even 100% on the rules on Earth, lol. Does anyone have any resources I could use to this end?

I'm not sure anyone fully understands the rules. There are some pretty nifty climate modeling bits of software running on big machines and they cant seem to predict whats going on.

Theres so many things to describe. We have talked about rivers a lot and how they are made and where they flow etc and theres no easy way to predict or describe that other than in simple terms like water flows downhill. Part of the issues are that much of the world is in balance where a number of factors adjust something which have knock on effects. Many political problems are caused from people desiring an outcome and making changes which they think will cause that outcome only to find that something unrelated and usually pretty catastrophic occurs too.

So are we talking about global stuff, regional terrain, local effects or large scale stuff ? Rock, rivers or vegetation ?

Sigurd
03-11-2009, 06:32 PM
Lots of affects to consider and not all of them are documented in any map.


Wind, climate, rainfall, seismic activity, pollution all impact land in ways not shown on most fantasy maps - and we haven't even touched on Magic. With many elements not explained you have a larger capacity to make things the way you want and call it 'realistic' - some unseen force makes it so.


You can make broad gestures - river flow always going down is a good one.

Old areas typically have more erosion.
Mountains next to trenches or canyons will probably be steep and young.
Evergreens in the north, palms in the south.
Seas are salty and deep. Rivers and lakes not so much.
Islands form in chains like the top of a ridge.
Coasts have a wild and random curve to them. They're best generated rather than drawn IMHO.


Personally, I find a great deal of 'realism' is a sense best satisfied by a random element. I question my decisions if I draw a coastline but I feel much more confident with a generated one that I 'discover'. I think its just an unnatural act to make land.


Sigurd

Kestenvarn
03-12-2009, 01:23 AM
I'm also interested in this. What forms weather patterns? What about plate tectonics? What about currents in oceans? I've heard having large oceans like several maps do would cause gigantic storms raging across the globe....

waldronate
03-12-2009, 02:43 AM
Weather is caused by uneven heating of the earth by solar radiation. This uneven heating causes air masses to move. The amount of heating of a given area and the change over time are controlled primarily by the axial tilt of the planet, year length, the size of the planet, the rotation speed of the planet, and atmospheric density. The axial tilt and year length determine the seasons and the min/max possible temperature in an area. Differential heating between the equator and polar regions causes flow of air toward and away from the poles. The size and rotation speed of the planet cause that poleward flow to be deflected to the side, causing the spin that shows in large storm systems. Atmospheric density determines the total energy that can be carried by a parcel of air.

Clouds form when water is evaporated from wet areas, rises, and begins to condense in the upper reaches of the atmosphere. Storms (great masses of clouds) occur when a body of (typically warm) moist air encounters a mass of cooler air. Storms generally gain moisture over bodies of water and lose it over land (more quickly over drier land such as desert compared to woodland or jungle). Larger oceans potentially allow larger storms to form but there is an upper limit dictated by atmosphere and world characteristics.

Surface ocean currents broadly follow atmosphere dynamics. Deep ocean currents follow the same sorts of rules as the atmosphere, but with the added factor that salinity has a major impact in addition to heat (saltier water is heavier than less salty water of the same temperature; warmer water is lighter than colder water). The Gulf Stream, for example, arises in part because cold water sinks just north of Iceland, pulling in saltier water from the tropics, which gets colder and sinks, pulling in more water, and so the current flows.

Plate tectonics arises due to differential heating in the mantle from the core of the planet. Hot rock rises and cold rock sinks. The continents are formed of much lighter rock than the mantle rocks and so float around, following the mantle currents. Then continents collide, mountains tend to form in the collision zone (see the Andes and Himalaya for excellent examples). When plates pull apart, oceans form (see the Atlantic ocean and the new ocean forming in the Red Sea / Africa Rift Valley). The hot rock that rises from the mantle tends to take the form of relatively small plumes. These hot spots break through the crust in relatively small areas. The motion of the plate moving over them can be seen from the action of the hot spot on the plate rock (see the Hawaiian island / Emperor seamount chain and the Yellowstone hotspot / Snake River Valley in the US). The mountains pushed up by collisions tend to be near the edges of plates. They start high (Andes / Himalayas) and erode down over time (see the Appalachian and Ural mountains). Alluvial plains are formed from erosion products of mountains (the great plains of the US are formed from debris from the Rocky Mountains and Appalachian mountains with a bunch of gunk scraped off Canada during the last ice ages).

OK, that's enough intro to geography for now. There are lots of great textbooks out there on this subject and many good college class websites. Physical Geography is what you're looking for.

Sorry about the long-winded spewing but sometimes I can't help myself.

overlordchuck
03-12-2009, 07:51 AM
/head a splode

Kestenvarn
03-12-2009, 08:13 AM
I find a good place to start to be Expeditious Retreat Press' free A Magical Society: Guide to Mapping (http://xrp.yourgamesnow.com/index.php?main_page=product_info&cPath=1&products_id=5)
This was really helpful, thanks.

Valarian
03-12-2009, 09:11 AM
Evergreens in the north, palms in the south.
Unless you're in the southern hemisphere, in which case it's the other way around :)


Islands form in chains like the top of a ridge.
Volcanic islands do. You can have island clusters caused by sea level rising and flooding low lying areas (e.g. UK, Ireland, Isle of Wight).

Korba
03-12-2009, 10:40 AM
I'm in the process of writing a climate guide FAQ at the moment but i'm not that far along. Waldronate's post is a great summary though.

One thing i would like to add is read about Hadley Cells (http://en.wikipedia.org/wiki/Hadley_cells). They define the genral bands of climate around the globe influncing the positions of grassland/forest/tundra/desert and tropical rainforest (then influnced by mountains and ocean patterns of course.

Korba

Midgardsormr
03-12-2009, 12:47 PM
A bit off topic, but I met a fellow at art school recently who was a geologist until a few months ago. I keep trying to goad him into joining this community to share his science with us.

Bohunk
03-12-2009, 03:42 PM
Weather is caused by uneven heating of the earth by solar radiation. This uneven heating causes air masses to move. The amount of heating of a given area and the change over time are controlled primarily by the axial tilt of the planet, year length, the size of the planet, the rotation speed of the planet, and atmospheric density. The axial tilt and year length determine the seasons and the min/max possible temperature in an area. Differential heating between the equator and polar regions causes flow of air toward and away from the poles. The size and rotation speed of the planet cause that poleward flow to be deflected to the side, causing the spin that shows in large storm systems. Atmospheric density determines the total energy that can be carried by a parcel of air.

Clouds form when water is evaporated from wet areas, rises, and begins to condense in the upper reaches of the atmosphere. Storms (great masses of clouds) occur when a body of (typically warm) moist air encounters a mass of cooler air. Storms generally gain moisture over bodies of water and lose it over land (more quickly over drier land such as desert compared to woodland or jungle). Larger oceans potentially allow larger storms to form but there is an upper limit dictated by atmosphere and world characteristics.

Surface ocean currents broadly follow atmosphere dynamics. Deep ocean currents follow the same sorts of rules as the atmosphere, but with the added factor that salinity has a major impact in addition to heat (saltier water is heavier than less salty water of the same temperature; warmer water is lighter than colder water). The Gulf Stream, for example, arises in part because cold water sinks just north of Iceland, pulling in saltier water from the tropics, which gets colder and sinks, pulling in more water, and so the current flows.

Plate tectonics arises due to differential heating in the mantle from the core of the planet. Hot rock rises and cold rock sinks. The continents are formed of much lighter rock than the mantle rocks and so float around, following the mantle currents. Then continents collide, mountains tend to form in the collision zone (see the Andes and Himalaya for excellent examples). When plates pull apart, oceans form (see the Atlantic ocean and the new ocean forming in the Red Sea / Africa Rift Valley). The hot rock that rises from the mantle tends to take the form of relatively small plumes. These hot spots break through the crust in relatively small areas. The motion of the plate moving over them can be seen from the action of the hot spot on the plate rock (see the Hawaiian island / Emperor seamount chain and the Yellowstone hotspot / Snake River Valley in the US). The mountains pushed up by collisions tend to be near the edges of plates. They start high (Andes / Himalayas) and erode down over time (see the Appalachian and Ural mountains). Alluvial plains are formed from erosion products of mountains (the great plains of the US are formed from debris from the Rocky Mountains and Appalachian mountains with a bunch of gunk scraped off Canada during the last ice ages).

OK, that's enough intro to geography for now. There are lots of great textbooks out there on this subject and many good college class websites. Physical Geography is what you're looking for.

Sorry about the long-winded spewing but sometimes I can't help myself.

Yes this whole post deserves quoting. Thanks Waldronate great post! Repped!

Nomadic
03-12-2009, 05:24 PM
Don't worry about getting too accurate. I studied world models and information for nearly 8 months in order to make the world I was working on realistic. Even after all that I still don't know even a fraction of everything there is to it. It did however teach me something important. Verisimilitude trumps realism when it comes to fantasy worlds.

Don't worry about getting it perfect, instead get yourself a good set of simple rules to use as a measuring rod. There are quite a few decent rules of thumb that you can remember. Doing so will make things alot easier. Even these have alot to them but they are alot easier then full blown research. Here's a fair bit to get you started.

- Mountains form where plates collide (Himalayas), where one plate subducts under another (Cascades), or where a hotspot burns through the crust (Hawaiian Isles).
- The younger the mountain the more jagged its peak. Young mountains such as the Rockies are tall and sharp. Old mountains like the Appalachians are short and curved due to erosion.
- Rivers start high and flow with gravity, always flowing along the path best able to carry them (generally the steepest one).
- Rivers come together, they don't split apart. They might break up around obstacles or meander through different paths over time, but these breaches are rarely longer than a few hundred feet to a mile or two with the river quickly resuming a single course.
- The only time a river doesn't meet is when the above happens right as it hits the ocean. If it meanders a bunch you can get a river delta at the mouth.
- The style of the river depends on the terrain. Fine sand and silt tends to create meandering rivers that have lots of switchbacks and oxbow lakes (the Mississippi) while rocky ground creates fast flowing, straight rivers (the Columbia).
- Deserts are formed where there is little precipitation falling. This happens mostly due to barricades that the moisture can't overcome. Rain shadows for example are a physical barricade. A mountain range blocks rain from reaching the other side and a desert forms. Other barricades exist such as prevailing winds pushing the moisture out to sea or very cold temperature that lowers the atmospheric ability to hold water. The final primary barrier is one that is often overlooked. Simple distance. Moisture can only stay airborne for so long before it comes down. That is why the interiors of large landmasses tend to be dry.
- Barriers divide groups as well as weather. People on the east side of a mountain range are probably going to be very different culturally than those on the west side. An animal on an island is going to be different then its cousin on the nearby mainland if neither can travel over or through the water separating them. Again large distances are a viable barrier.

There is of course much more to learn, but just keeping a simple library of important facts will allow you to make acceptable worlds.

Yoscha
05-07-2009, 08:00 AM
I've written some tutorials about topics such as climate, shore lines, rivers, etc. specially aimed at people who want to draw quite realistic maps.
I'm a geologist, so I have few problems to do it 'realistic', but some people I know had quite some problems, so I started to write those tutorials.

The only problem is, they're all written in German, but if you're interested I could try to translate them, though it might take some time and some proofreaders will probably be needed.

Novarri
05-07-2009, 11:57 AM
some proofreaders will probably be needed.

I'd be glad to proofread, if you translate them.

ravells
05-07-2009, 01:58 PM
I question my decisions if I draw a coastline but I feel much more confident with a generated one that I 'discover'. I think its just an unnatural act to make land.
Sigurd

Tell that to Slartibartfast!!

Yoscha
05-08-2009, 05:33 AM
I'd be glad to proofread, if you translate them.

I'll remember it :).

Gidde
05-08-2009, 01:24 PM
I feel the same way as Sigurd's quote above.

Case in point: I spent last weekend (and much of monday evening) devising a world from the tectonic plates up, complete with hotspots. The end product ended up looking like I had generated it with FT or PlanetGen ... only not as pretty. I think I'll just stick with a generated map for landmasses and make the terrain/climate as realistic as possible.

I'm glad we have actual geologists around to catch us when we blatantly ignore the way geology works, though :)

pickaboo
05-13-2009, 07:29 AM
Oh my. To bring my 2 cents into this, I often search the Earth map for similar features than my own work. It's nice to see such simple guidelines :)

alaskanflyboy
05-18-2009, 05:00 PM
Given science still hasn't quite figured it all out, it's safe to say that most of us will not hold it against you if you don't either. The world is incredibly complex and would take far more computing power than I believe all of the members here have combined. Using simple generalizations as mentioned before will get you pretty darn close though. Saying "water flows down hill" and putting it in practice creates good results, but the reality is that water takes the path of least resistance, it's sooner go through loose sand than solid granite. I'm content to use erosion simulation in Wilbur even knowing runs as if the entire planet is composed of the same material.

I'll concur that Waldronate has a great summary of the basic forces at work in a world, and feel free to get as complex as you like. New, and fascinating, techniques arise when people seek to go beyond the norm.

Ryan K
05-21-2009, 10:36 PM
Just thought I'd throw this in - it's taken from a sign outside the Bureau of Meteorology in our building:


"Imagine a system on a rotating sphere that is 8000 miles wide, consists of different materials, different gases that have different properties (one of the most important of which, water exists in three different states), heated by a nuclear reactor 90 million miles away. Then, just to make life interesting, this sphere is oriented such that, as it revolves around the nuclear reactor, it is heated differently at different times of the year. Then, someone is asked to watch the mixture of gases, a fluid only 20 miles deep, that covers an area of 250 million square miles, and to predict the state of that fluid at one point on the sphere two days from now. This is the problem that Weather Forecasters face every day."

palehorse
05-21-2009, 11:57 PM
I was working on a map commission awhile back for someone who wanted an Earth-analog with the terrain modeled as realistically as possible. (That he wanted me to render it in what's probably my most artistic style - the one I use that's easily the least suited for that sort of thing - should have tipped me off right off that bat that he didn't know what it was he really wanted.)

Anyway, he sent me this big list of requirements, and I buried my head in the books and maps for a few days to get it right. When I sent him the first draft of the map, he came back with this rambling list of complaints, including one that, based on what he knew about geography, a certain river in this worlds version of Asia couldn't possibly be going the way I had it.

I pointed out to him that that particular river was, in fact, the Yangtze, which really does flow just like that.

Shortly after that I stopped working on that particular map.

Long story short, I'd just echo what Alaskanflyboy and Nomadic said. The list of simple rules that Nomadic posted is a perfectly good set of rules for 99% of the gaming world out there and will get you more than close enough for horseshoes and hand grenades.

(One good thing about working on that map though. I learned a lot about India's rivers; fascinating stuff, really.)

Ascension
05-21-2009, 11:57 PM
You mean they can't do that yet? :) kidding. In my small lifetime I can see vast improvements, when I was a kid they couldn't predict if we'd get rain or not if it was currently raining on my house and now we plan hurricane routes.

palehorse
05-22-2009, 12:03 AM
You mean they can't do that yet? :) kidding. In my small lifetime I can see vast improvements, when I was a kid they couldn't predict if we'd get rain or not if it was currently raining on my house and now we plan hurricane routes.

Over a very short time frame the good ones are pretty freakin' amazing. Seriously, I lived in Oklahoma for nearly 20 years, and the meterologists there literally saved lives every single year through their ability to figure out where tornadoes were about to form and to track them once they did, and let people know when it was time to get to your storm shelter.

Ascension
05-22-2009, 12:32 AM
Agreed, how they do what they do is Greek to me but I'm glad that they do it.

Caleb
06-09-2009, 06:10 PM
Agreed, how they do what they do is Greek to me but I'm glad that they do it.

Hahaha, took me a minute to compute that sentence. But I got it.


Though yes, meteorology has come very far. In about 2000, some news stations in California would boast about their new radar, (Doppler). And now, every news station has one, and they just keep getting more and more accurate.

It really is astounding when you look back about 200 years ago, and farther, and how people back then relied on animal signs, and cloud formations to predict weather.

Wyldabeast
08-04-2009, 02:30 PM
Great thread, I've gathered a good deal of ideas just reading over it!