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Mapmaking, Geography & Science!

Updated: Jul 7, 2021

There is a very obvious connection between mapmaking and geography and this little article is going to talk about how you can use things like geography, geology, weather patterns and our understanding of science in general to create great looking maps full of interesting features!

Here's a quick little definition of what a map is from “a representation, usually on a flat surface, as of the features of an area of the earth or a portion of the heavens, showing them in their respective forms, sizes, and relationships according to some convention of representation”

So already there is a lot of vague wording here and every map is simply trying its best to represent a world as best it can. Even satellite maps on earth, while tremendously accurate can't emulate real life as that wouldn't be practical or even necessary. Instead we want to look at some of the best known examples of geographic features on earth and try to understand why they are like this in order to translate that over to drawing a fantasy map.

While this list is not exhaustive, hopefully it can help someone new to mapmaking create a more solid base for a map.


Tectonic Plates

This is the main reason earth looks the way it does. Instead of a solid crust, earth is comprised of a series of smaller parts or plates that smash together, pull apart and grind along one another at incredibly slow speeds over millions of years. This changes the position and shape of the continents and oceans and affects all the other things I’m going to talk about in this article.

For this to help with making a map, the first thing you need to understand is that the shape of tectonic plates are not governed by any particular rules, at least on earth they formed at some point if the very distant past pretty much randomly in shape. You can make a bunch of winding weird scraggly lines all over a piece of paper and connect them to make the plates you need. But if your having trouble remember plates are usually larger than continents and just as random looking.

After you have a few plate lines on some paper you now need to understand the different types of fault lines along the edges of your plates, these are very useful!

Transform boundaries occur where two plates slide, or perhaps more accurately, grind past each other along transform faults, where plates are neither created nor destroyed. The San Andreas Fault in California is an example of a transform line. These typically dont make volcanoes, but are hotspots for earthquakes!

Divergent boundaries occur where two plates slide apart from each other. At zones of ocean-to-ocean rifting, divergent boundaries form by seafloor spreading apart, allowing for the formation of new ocean basins. Africa's East African Rift and Valley and the Red Sea, are examples of divergent boundaries.

Convergent boundaries occur where two plates slide toward each other to form either a subduction zone (one plate moving underneath the other) or a continental collision. At zones of ocean-to-continent subduction. The Andes mountain range in South America, and the Cascade Mountains in Western United States are examples of convergent fault lines.

You can add these different types to the lines you have created with arrows. As an example I found a continent generator and created a supercontinent, I then put an overlay over it to make my own simple tectonic plates. You don't need to worry too much about what lines go where, the exact nature of why a line is either Transform, Divergent or Convergent is mostly random and doesn't seem to follow any specific rules. At leastits not worth worrying about in a fantasy world at any rate.

Tectonic plates can do alot for your world beyond mapmaking but perhaps the biggest advantage it can have is that you can now place down mountains and volcanoes in very realistic ways on the map. The himalayas for example are a huge mountain range on earth because the Indian plate is sliding under the Eurasian plate creating a buckle in the earth that rises up forming a mountain range. The Andes in South America are another mountain range that is very obviously created by plate tectonics in a similar fashion as a plate slides under the south american plate.

Volcanoes are also very likely to occur around fault lines and can add some nice features to a world or region map! If you have your tectonic plates worked out roughly you know pretty much where to put them!


Temperature Maps

If you are starting the map making process for a whole world or region and are not sure where to put down forests, deserts and jungles etc then the best thing you can do is look at temperature maps. Overlaying something similar on top of the continents you might have made will mean you can quickly figure out where cold and hot areas will be and give you a better understanding of the climates, biomes and environments. On earth the temperature map is based upon a whole host of things and is not uniform across the globe.

But to give a good example of how this might work, below is a simple uniform temperature map with our supercontinent and you can now clearly see where the cold areas of the map would be, where the really hot areas are and most likely in this specific case a massive super desert on a massive scale in the middle but that's another story entirely!

Of course you can make your own temperature map and make it colder or hotter depending on your world and what kind of map you want!


Weather Patterns

On earth our weather patterns can be just as important to why a region is hot or cold than its overall position on the temperature map. You can study weather patterns in more detail to create some weird and wonderful environments for a fantasy world and I will cover just a few here.


Wind doesnt normally cause environmental change on a large scale, at least not enough for it to be worth it for a fantasy mapmaker, but there are a few expectations. The biggest real world example is the dust and minerals in that dust from the Shahara desert in Africa blowing across the Atlantic providing essential fertilizer for the Amazon rainforest where it compensates for poor rainforest soils. The Amazon might only exist in its current form, thanks to the winds coming from another continent. Worth bearing in mind for fantasy maps anyway!

Rain Shadows

A mountain range typically creates a dry area on the side opposite a body of water like an ocean or sea. The mountains block the passage of rain-producing weather systems and cast a "shadow" of dryness behind them. Wind and moist air is drawn by the prevailing winds towards the top of the mountains, where it condenses and falls before it crosses the top. This also means that rivers almost always form on the sides of mountains facing the oceans of a world with very few exceptions.

Ocean Currents

Huge moving bodies of water, currents are critical for the health and movement of oceans and without them the oceans would stagnant. Ocean currents also influence the temperature of the regions through which they travel. For example, warm currents traveling along more temperate coasts increase the temperature of the area by warming the sea breezes that blow over them. Perhaps the most striking example is the Gulf Stream, which makes northwest Europe on earth much more temperate than any other region at the same latitude.

This can make a big difference when creating a coastal region and doesn't need to be very detailed, a simple does a warm or cold current run along the coast or not might help define how that region looks overall.

Now our little map has some ocean currents, we can start adding in some simple biomes and environments!