sketch of the author's fictional world

Just to say this first, the map is intentionally on a slant, and so the Northern cold areas are displayed at more of a North-West Angle, for example.

I am designing the world from scratch, and am about halfway done. I'm concerned about the placement of my biomes and the paths of my rivers, mostly.

Are my biomes unrealistically placed in relation to each other?

Are my rivers starting in places a river couldn't start, and are the paths they follow too deliberate or just wrong?

I'm aware the coastlines need work. I plan to further design the coastlines after this.

  • 2
    $\begingroup$ Welcome to WorldBuilding Teqa! If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$ – Secespitus Dec 9 '17 at 18:46
  • 4
    $\begingroup$ I assume that the rivers on the map are not only actual rivers, but rather highlights of the biggest ones? Do you have any explanation / lore why are the two islands to the east entirely jungle? Why is the jungle biome almost next to tundra, does it include chinese-style bamboo forests? $\endgroup$ – Nuloen The Seeker Dec 9 '17 at 18:47
  • 1
    $\begingroup$ The rivers are mainly just the larger rivers. And, with the jungles next to the tundra, actually it does, I'm surprised you guessed that without any information! I plan to have the jungle switch from more of a bamboo styled forest to a more regular dense jungle closer towards the edge of the continent. With the two large islands, I honestly just was not entirely sure what to do with them, and thought "Wow it'd be neat if they were abandoned civilizations that had been left to overgrow with jungle and plant life. I think I should probably add more diversity to them, though. $\endgroup$ – Teqa Dec 9 '17 at 19:05
  • 5
    $\begingroup$ You should add a compass to the map. Rivers flow from higher areas to lower areas and don't split (there's always exceptions, but that's the general rule). Lakes can have multiple rivers feeding them, but only have one leaving them. To mention a few things.. $\endgroup$ – dot_Sp0T Dec 9 '17 at 20:16
  • 2
    $\begingroup$ You know, most natural phenomena which cause polar sort of effects, also cause natives to define north-south to align with the poles. Barring, you know, lake or ocean effect, for instance Vancouver never freezing even though it's north of Washington DC which freezes all the time. A reason to tilt a map might be because the map's subject fits a rectangle better when tilted, e.g. West Virginia or Afghanistan. $\endgroup$ – Harper Dec 10 '17 at 20:42

Some advice here, before I dissect your map in my giant answer: it would be really, really helpful to anybody trying to evaluate the map if you had at least the latitude lines on it (longitude would be nice, but isn't really relevant to climate). It's also useful if your map is in a known projection when presented for evaluation and/or while editing, even if you intend on a different final version; I would recommend an Equirectangular projection, because those are extremely simple and easily parsed by a wide variety of programs. I'll give you what pointers I can about climate problems (and why your map has other problems), but in the future try to work based on a known map projection for ease of use and evaluation.

First, the problems with the map itself.

Right now, with the tilted map you're using (the latitude lines would probably be diagonal if drawn on it, as I assume the icy areas are near one of the poles), I can't identify several key properties about your world, so I have a hard time estimating how accurate your biomes are. Predicting the ocean currents or wind patterns requires latitude lines, as well as knowing which way the planet is spinning (clockwise or counterclockwise; this alters their direction), and those are both needed to accurately estimate rainfall or temperature.

I can't even be sure where your equator is right now, but based on your scale (another problem: any fixed scale is inaccurate when applied to a map projection, especially on a planetary scope, so that scale will actually change depending on which part of the map you apply it to; just try moving around the world in Google Maps and watch how the scale bar changes even without adjusting the zoom) and assuming that this planet is approximately Earth-sized (meaning a circumference of roughly 40,000km, so about 10,000km along the surface from either pole to the equator), the equator would be somewhere to the southeast of what you have displayed. In other words, you're only showing one hemisphere, and not even all of it, because even taking your map at a diagonal is probably not 10,000km based on your (flawed) scale. If your planet is materially smaller than Earth, it's far enough from Earth-like that you're going to need to estimate gravity and air pressure as well, making your job even harder.

Now, to the climate.

First, your jungle biomes are hideously out of place. Tropical conditions are essentially defined as high monthly temperatures (18C or greater) year-round with at least moderate rainfall (without enough rain, you get deserts). The tropic lines (Cancer and Capricorn) are the outer limits of where you'll find tropical conditions, as these only really appear near the equator; beyond equatorial regions, seasonal variation becomes too great and you end up with temperate or continental climates.

As such, having jungles anywhere even remotely close to taiga/snow forest (which you need to clarify; snowy forests are mostly taiga, and tundra doesn't have trees if that was what you meant) is utter absurdity; taiga requires temperatures below 0C several months of the year, and often the warmest month will not reach the 18C average that is considered the minimum for tropical conditions. Assuming an Earthlike axial tilt (about 23 degrees; this is where you find the tropic lines), there's going to be at least 20-25 degrees of latitude between tropical regions and taiga regions, probably more. I'm referring to the Koppen climate classification, if you want to read up in more detail (tropical biomes make up the A group, with tropical rainforests as Af; taiga would be the colder continental areas, mostly Dfb or Dfc).

Your rivers are also flawed. As sphennings has already said, rivers flow downhill, not up, so any river heading into a mountain range is wrong; they might start in a mountain range, but barring some very deep valleys that you don't have marked, they won't flow through them. They also converge into one another except at deltas; rivers have on occasion been known to split, but it's quite rare and not a lasting phenomenon (one side of the split will draw more water and erode faster, and eventually the other side will simply dry up as the full flow goes to the other branch), so don't make them spread out as they go until right before they hit the ocean.

Rivers flowing out of lakes follow a similar principle, which you should keep in mind. Multiple rivers might flow into a single lake, but only one river should be flowing out from it. That southern continent (all forest/grassland) has a particular example; I count three rivers connected to it, and all three end in the ocean, which is unrealistic in the extreme. Two of those (I would suggest the southern two, because the tributary river that merges into the northern one has a direction that suggests it's going to the ocean) should be flowing from springs or mountains into the lake, and only the third should be continuing on to the ocean.

The southeastern desert island is also horribly, horribly wrong. You have a lake surrounded by mountains, which are surrounded by desert; that lake will not last, and you certainly won't have nice grasslands around it. It's going to look more like the interior of Australia than anything else. That interior mountain range is also suspect, from a tectonics perspective; isolated volcanic mountains can pop up almost anywhere due to hot spots, but ranges are typically formed by plate collisions, which means most ranges are near coastlines. There are some other cases where they result from ancient collisions (North America's Rocky Mountains; the west coast has two separate mountain ranges) or the collisions are inland (see the Himalayas), but your inland mountains don't really fit either bill.

Precipitation there comes from moisture blown in over the ocean, but as the clouds rise up the mountains they will rain themselves out on the opposite side from the lake; this is known as orographic lift or rain shadow. When the clouds get over the mountains to your lake, they will have little moisture left, and since it gets warmer as the clouds drop (preventing condensation and rainfall), that moisture will not fall as rain near that lake. You'll most likely get rivers flowing out from the mountains to the northeast, towards the non-mountainous coastline. The southwestern side (as seen from your map) of that continent would be bone-dry apart from the immediate coastline, due to the outer mountain range that would suck up any rainfall.

Without latitude lines, I can't predict what ocean currents would flow around that continent, so I can't tell you for certain if the coast would ever receive any real rainfall; if you end up with cold currents flowing past the coast, it's going to turn out extremely dry (you wouldn't even get the rain shadow effect, most likely, so you'd get lots of fog and clouds but next to no actual precipitation: see northwestern Africa). My best guess (based on my guess that it would probably be a warm current) is that the northeastern side will probably end up a lot like either Egypt or India, with distinct wet and dry seasons; either floodplains with one or more rivers that flood annually like the Nile, or a more general monsoon that brings lots of rain in some months and is dry for the rest. The latter scenario would probably produce savannah (Aw/As climates in the Koppen classification) and/or steppe (BS climates) biomes, the former would be a desert (BW climates).

  • 3
    $\begingroup$ Observation on snow being next to jungle - this is correct, unless there is a dramatic difference in elevation. Hawaii, which is primarily forest/jungle, routinely has snow on its volcano peaks, and the Andes mountain range creates a rapid change from desert to jungle to tundra. Some topographic lines on this map would help a ton on determining whether such variation is reasonable here. Also prevailing winds, typical rainfall, etc. $\endgroup$ – brichins Dec 11 '17 at 17:47
  • 2
    $\begingroup$ @brichins True, having a sudden 1000+meter spike in elevation can screw up a lot of normal expectations, and a sufficiently high-resolution map will show as much. When you're trying to sketch out the broad sweeps of climate so you have a general idea of what's going on, that little fact becomes less relevant, especially in the absence of detailed altitude measurements (this one just has sea/land/mountain for elevation). $\endgroup$ – Palarran Dec 11 '17 at 17:56
  • $\begingroup$ Wait, based on "if you end up with cold currents flowing past the coast, it's going to turn out extremely dry", Vancouver and Seattle are dry. Which is far from the case. (There is a cold current flowing down from alaska along the west coast of north america) $\endgroup$ – Yakk Dec 11 '17 at 18:34
  • 1
    $\begingroup$ @Yakk Look more closely, like at the maps here. The Alaska current is actually a warm one, going north from where a Pacific current hits the continent; the cold current you're thinking of is the southern branch from that point (about 40N), which is off the coast of California (which is indeed significantly drier than Vancouver). $\endgroup$ – Palarran Dec 11 '17 at 18:58
  • $\begingroup$ @Palarran oceanography fail on my part. :) $\endgroup$ – Yakk Dec 11 '17 at 19:38

Your rivers are unrealistic.

Three of your rivers flow towards mountains on their way to the sea. Water flows downhill not uphill.

Small rivers tend to aggregate into larger ones, not the other way around. You seem to be mistaking the behavior of a delta with the behavior of the river as a whole. Most of your rivers branch out as they approach the ocean. While real world rivers tend to collect together.

Many of your rivers share the same source and flow in different directions with another river.

You have rivers on your central island that start randomly and end randomly without emptying into a body of water.

  • 2
    $\begingroup$ *insert "aliens" meme, but with "ravines" $\endgroup$ – Nuloen The Seeker Dec 9 '17 at 18:49
  • $\begingroup$ Thank you, I was constantly questioning whether I should have the rivers branch out, and in which way. For the ones near the mountains, I was thinking that the river might head towards the mountain, they might be stopped by them and head around and in between the mountains, creating deep valleys with rivers in them between the mountains. Is that not likely to happen? $\endgroup$ – Teqa Dec 9 '17 at 19:10
  • 2
    $\begingroup$ That's a fijord, not a river. $\endgroup$ – sphennings Dec 9 '17 at 19:15
  • 1
    $\begingroup$ A fjord can have a river flowing into it. But it isn't formed by the river. The critique I was leveling is that a river won't flow up over a mountain range to create a valley through it. $\endgroup$ – sphennings Dec 9 '17 at 20:40
  • 8
    $\begingroup$ @Teqa There are rivers which thread across mountain ranges (the Delaware Water Gap is an example), but these are somewhat rare, and only happen when the river is older than the mountains. Basically, the river eroded its bed faster than the mountains grew - at no point did the river flow "up" the mountain. $\endgroup$ – R.M. Dec 9 '17 at 21:26

I am skeptical about the mountains. There does not seem to be a pattern to them, island to island. And they are clustered on the coast.

You can have mountains on the coast. Check out this topographical map of Peru. http://coolsummerstore.com/topographical-map-of-peru.html topo map of peru

Back your mountains off the coast a little bit. Then imagine: the mountains are being pushed up by a plate that continues under the ocean. Mountains on one island would be a continuation of that plate and you could follow the range from one island to the next.

Most realistically, the islands themselves would be a continuation of the same process that lifted the mountains. Check out Sumatra: two tectonic plates are colliding just off shore, and this process is lifting the land that makes the islands of Sumatra and Java and also smaller adjacent islands.

map showing Sumatra trench https://en.wikipedia.org/wiki/Sumatra_Trench#/media/File:Map_of_the_Sumatra_Trench.jpg

Here is an idea for making new lands from scratch if you want them to be realistic: do not make them from scratch. Take existing lands and use that map. You can tweak shapes, look at a top map and raise water levels, imagine if the mountains had weathered away. But you will have a solid real world basis to work from - like the curry pie I am currently working on, starting from a standard pumpkin pie recipe so I do not screw up the basics.
What tool can I use to draw a simple map of a fictional world?


In addition to things pointed by others the vulcans seems off. usually they form a ranges at the meting of two tectonic plates - see for example ring of fire maps:

Ring of fire map showing lines of vulcanos

I have hard time distinguishing vulcanos from mountains on your map but the creation of both is usually roughly the same (crashing one land mass to another).

Deserts seems to be rather off. The closest you have to that in real life is Australia and even that it is a) rather big and b) desert is in the middle. It is not entirely impossible as you can have a rain shadow or fog desert but this requires a mountain configuration. The island on the bottom right on the other hand seems to have north-eastern winds based on presence of savannah there. Barring that I would expect that middle was desert while the shores would have more continental climate.

Climate map of Austrailia

Contrary to others I think it might be possible to have lake in middle a deasert though I would expect it usually to be too salty to affect the area too much. I would worried about the size of basin though.

I would presume that if you have 'snowland' that you should have pole-like ice sheet connecting them. They have very important role on shipping and climate so it might be good to consider what are the variations of them.


Cold biomes running in an angle could be caused by cold sea currents, however that would mean that warm winds would often come from the south and that would bring humidity to the south-east island, so I would play a little bit with the mountain range, or add some seasonal rivers leading into the lake in the middle.


What happens on the rest of your world? The map you have given would fit within the continental U.S.

Worlds are big.

If you want to make a realistic world, then start by doing some reading about geology. While you can play fairly fast and loose you will get a more realistic world if you think about plate tectonics.

Build the landforms first, and give them topography -- elevations.

Figure out your wind patterns. Consider: Australia has mountains on the east cost, that catch the prevailing easterlies. Move the whole thing south by 15 degrees, and the prevailing winds are westerly. This gives you a much wetter interior.

Figure out where your monsoon areas are. The driving force behind monsoons is usually a large continental mass that heats up in summer and cools in winter. Central Asia is the driver for Indian and SE Asia's monsoons.

Now, with topography, wind patterns and monsoon patters you can sketch a rainfall map.

With latitudes, coasts, and wind, you can sketch a temperature map.

Wet-warm tropical jungle. Wet-cool temperate rain forest. Dry-warm tropical deserts. Dryish warm tropical savanna Dry-cool temperate grasslands. Dry-cold tundra

Right now it sounds very messy.

An easy way to figure this out is to read the wikipedia articles on things like Monsoon, Desert, Tropical rain forest, tundra, stepp. Hardwood forest... and find what makes them tick. E.g. California and the mediterranean have very similar climates. Figure out why.

MANY sci-fi worlds are badly done just because they are homogenous. Arrakis (Dune) is a desert world. And there are reasons the come out later for this, but an inhabitable world would strain credibility to be of just one time of ecology.

Look at the variation just in the U.S. or in Europe. Orange growers in Florida panic when temperatures get down to freezing. I live where there is ice on the ground for 6 months of the year. I get 16-20 inches of precipitation a year, my sister in the San Juan islands gets 3-4 times as much, and snow is fleeting.

The native ecology here is poplar trees and grassland. 200 km SE it's grassland. 200 km NW it's boreal forest.

It would be very cool if someone has built a "planet simulator" with ways to get rough climate given the geography, spin, insolation, year, inclination. Don't know if anyone has.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.