What does a Map bring to a Story

(Part one)

Thanks to Chris Large, Geologist Extraordinaire (and writer of spec fic)  we have an insight into how writers can bring more verisimilitude to our world building through maps.

Take it away, Chris.



A map is a pretty standard accompaniment to a fantasy novel, right? You’ve built a completely new world. You’re proud of it, and how well it all fits together. “And look here,” you say, “it’s all on this funky little map.”

Fine, that’s great – but why? I don’t know the exact landscape of Italy, but I can still read a book set in Umbria without feeling the need to refer to a map.

To a writer, a map represents a series of obstacles her characters must overcome to reach their goal. It can also add depth to her tale, provide her characters with a home, and her readers with a feeling of ‘place’. In the real world however, a map is a representation of the effects of natural land-forming processes on the countryside. These processes are occurring both at surface by way of weathering and erosion, and below the surface in the form of tectonic, mountain-building stresses. Now I’m not suggesting all sf/f authors get themselves down to their local university for a crash course in Geology 101 (though it wouldn’t hurt), but when world-building, paying attention to natural processes will lend authenticity to your landforms and waterways, and give you a much more visually appealing result than simply pushing a river through here, and plonking a mountain down over there.

So what does a map bring to a story? Nothing if its mountain ranges, glacial valleys and winding rivers are geologically ridiculous. In fact, in the same way that a hessian sack will obscure the killer curves of a gorgeous supermodel, a poor map can significantly detract from a ripping yarn. If you include a map in your story, shouldn’t a reader reasonably expect the landscape to play at least as significant a role as one of your main characters? Surely a black and white depiction of Brave New World’s supple hills and sensuous valleys is akin to the opening description of one of its deadly heroines. But you wouldn’t make the mistake of writing a (human) character with a mouth in her ear and four butt cheeks, so why create a map with equivalent flaws?

“Don’t be so pedantic!” I hear you cry. “It’s fantasy!” Okay, but as a writer you don’t want to look foolish, and as a reader you will lose confidence in a story without a solid foundation. Let me give this (slightly tangential, but bear with me) example of an Original Series episode of Star Trek called ‘City on the Edge of Forever’. Ruins dating backten thousand centuries are discovered on the ‘Planet of Time’, apparently dating it as the oldest planet in the universe. However ten thousand centuries is only one million years. The Earth, which is far from an old planet, is thought to be around four and a half billion years old. Way to go Captain K.

So the Earth’s geological history is long, and humans have been around to witness only a tiny fraction of it. If you’re writing about a world similar to Earth – be it populated by elves, gnomes, trolls, whatever – it’s likely to be of a similar age, and to have undergone similar land-forming processes, and will therefore have similar rocks, mountains, and ore deposits.


It will not, (as I have observed on some maps) have water that runs uphill. Yes, rivers love to flow toward the sea, but under no circumstances will they run over mountain ranges to get there. Neither will they weave strategically between the foothills of the aforementioned ranges, because even though foothills may be little more than the annoying whimsy of your publisher’s cartographer, they still represent high-ground. Water is reasonably predictable in so much as it generally flows in the same direction as gravity’s pull, so unless the dread wizard Aarchon Demonstricus is exerting the mighty power of Jawlock’s Amulet of Fantastical Water Summoning from his secret mountaintop lair, running water will normally stick to lowland regions. If you’re unsure which way is up on your map, try sketching on some contours. It makes things a lot easier.

This said, and once again acknowledging that rivers absolutely and positively adore making for the sea, mature river systems generally won’t strike across county like a sprinter who really, really needs the can. Rather, they will take their time, meandering casually across the flood plain with all the enthusiasm of a pensioner making his way back to the retirement home bus, after a leisurely afternoon of lawn bowls with his mates. The older the river, the more pronounced the meander. This is because water runs fastest around the outside of a river bend, eroding the bank, and slowest around the inside of the bend, depositing sediment previously held in suspension.

People build along rivers because they need water to survive but they can pay a price for this.  Flooding can wipe out a town or a crop. Or flooding can fertilize the land, as it is in Egypt. The Nile flooded every year, bringing rich sediment to the soil and making farming possible. The locals built their lives around these floods. When the floods didn’t come there was famine. Rivers were also used as highways. The Vikings travelled all over Europe via major rivers, settling where Moscow is now, which is where the name Russia (Rus) comes from. So the writer needs to consider which kind of rivers they have in their world and how the locals use these rivers.

While we’re on a watery theme, inland water cannot exist in isolation. A lake without a feeder is akin to a barfly without a scotch: it’s either faking it, or it’s only there for messy, late-night sex. Sure, transient water such as that found in salt pans can exist on rainfall alone, but as soon as the rain stops, the pans will dry. Permanent lakes require continuous feed, and that means large catchments and significant supply via creeks and rivers. A glacier is a great source of slow feed for a lake.


But water is only one side of the story. How about mountains? Where do they spring from? Are they the equivalent of acne, popping up unwanted and unheralded across the face of your map? Or is there a more quantifiable mechanism at work? There are two easy ways to build mountains. One is by compressing the landscape until it folds and buckles, the other is by volcanism.

If you apply lateral compression to your landscape it has little choice but to either fold, or fault. If the rocks are ductile they will fold, if they’re brittle they will fault. In the case of faulting, one block will ride over the top of another, creating mountains. Equally, if you apply extension, or pull your landscape apart, one block will drop, creating a valley.

On Planet Earth, the process of plate tectonics dictates where and how the Earth’s crust is created, and where it’s destroyed. A series of mid-ocean ridges are the birthplaces of new crust (and potentially represent the spawnpoint of all life on Earth). Convecting magma from the mantle or asthenosphere, erupts onto the seafloor at divergent margins. To make way for new crust, the plate must move. Where the mobile plate meets a static plate, the mobile crust is subducted and remelted, often resulting in volcanism. If you want to see an example of how to apply this theory retrospectively to a well-known fantasy world, you can read my short piece entitled, “The Tectonics of the Misty Mountains,” appearing next year in Andromeda Spaceways Inflight Magazine # 51.

The above theory is dependent on crust being destroyed at the same rate it’s being created. Some geologists don’t believe this is the case, suggesting instead that the crust is destroyed at a much slower rate, and that the Earth is therefore expanding. Of course your characters aren’t going to stand around debating which of the various mountain-building processes are most likely apply to what mountain ranges, but at least if you know, things will make sense on the map.

And how your characters interact with the landscape has to make sense. Say the writer decides the mountains in their world are products of volcanic activity, which is still hissing away. How is this going to affect the people who live in the region? Can they harness the steaming water? People build close to volcanoes because the soil is particularly rich. But, like rivers, there’s a price for this soil as the volcano may erupt again. Do the locals have myths about past eruptions and buried villages?

If the writer’s characters are living in a mountainous region, how they farm will be affected, (terraces, anyone?) as well as how they travel. (Wheels aren’t much use in steep, rocky terrain). If the mountains are particularly high, they will affect rain flow, so the villages on the inland side will be dryer and could struggle to make a living from the soil, while the villages on the coast side will get more rain and live a more comfortable life. This could set up conflict between the two kingdoms. Now you see why where you put the mountains, the type of mountains and what effect they have on the land is important.

Next week see Part Two: Rocks and Ore Deposits, oh my!


Chris is a mineral explorer and has spent more than 15 years looking at rocks, sawing them in half, drilling holes into them, licking them, and sticking little eyes on them and giving them to his kids. Many of those 15 years have been spent in a tent in a desert. He now writes from home in Hobart while completing a MSc in Economic Geology.

See Chris Large’s blog here.

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