Map creation · Part 3 · About 10 minutes
Terrain is a price list
Relief is the only creation setting that appears directly in a construction quote. A height difference along your route becomes a multiplier of up to five on what the road costs — and the same terrain that raises the price drives away the settlements that would have justified it.
The one-minute explanation
Four controls decide the physical character of your land: mountainousness, mountain ranges, mountain layout and maximum elevation. Two more decide how wet it is: vegetation lushness and river density.
They are usually read as scenery settings. Only one of them is:
That last term comes from the relief you generated, and it ranges from 1.0 to 5.0. Nothing else on the creation screen enters a build quote so directly — which makes relief the second most consequential decision on the screen after total area.
How a height difference becomes a price
The terrain factor is not read from an absolute altitude. It is computed from the difference in height between consecutive points along your path, averaged over the whole route:
| Height change between steps | Difficulty | Reads as |
|---|---|---|
| Under 50 m | 1.0 | Flat |
| 50–200 m | 1.5 – 2.0 | Rolling |
| 200–500 m | 2.0 – 3.0 | Hilly |
| 500–1,500 m | 3.0 – 4.5 | Mountainous |
| Over 1,500 m | 5.0 | Extreme |
Three things follow from differences, not heights, being what is measured.
A high plateau is cheap to cross. Sustained altitude with little variation scores near 1.0. It is the climb onto it and the descent off it that cost, not the elevation itself.
The average is over the whole path, so detours pay. One brutal segment is diluted by the flat kilometres around it. This is exactly why the route preview is editable — dragging an anchor around a ridge does not just shorten the hard part, it lowers the multiplier applied to the entire road. Roads: grades, tolls and upgrades covers the editing.
There is no tunnel through a mountain. On the national map, tunnels are a water-crossing option. High ground is not bored through — it is simply priced. Relief is a bill you pay, never an obstacle you engineer away.
Mountainousness and maximum elevation are different questions
This is the most common confusion on the creation screen, and the two settings genuinely do different jobs.
It reshapes the distribution of land heights. Low values push most of the country toward lowland with a few peaks; high values lift the bulk of it into upland with lowland becoming the exception.
The generated heights are relative. This setting is the real-world number the highest point maps to, and every other height is scaled against it.
They are not independent in effect, though, and this is the part worth internalising: the terrain factor is measured in metres. Maximum elevation is the conversion from relative height to metres, so raising it stretches every height difference on the map — including the ones along your routes.
Low mountainousness, 8,000 m maximum
Most of the country is lowland and cheap to build across, but the few mountainous corridors are savagely expensive. A country of easy plains with hard walls between a handful of regions.
High mountainousness, 1,500 m maximum
Most of the country is upland, but nothing is very tall, so height differences stay modest. Construction is uniformly a bit expensive with no impassable corridors — a hill country rather than an alpine one.
Case B is the setting most people actually want when they ask for "mountains" and get a map they cannot afford to build on. If your complaint is that everything costs too much, lower the maximum elevation before you lower mountainousness — you will keep the landscape and lose the surcharge.
Ranges and layout: where the relief is organised
Mountainousness sets how much high ground exists. The next two controls decide how it is arranged, which is what determines whether the mountains are an obstacle you route around or a maze you route through.
Near-parallel bands, spread across the country at low angles. Long and continuous, with clear gaps — obstacles with identifiable passes, which makes for readable trunk-route planning.
Shorter, narrower massifs at random positions, plus about three times as many isolated peaks. Nothing is a wall, but nothing is a clean corridor either.
A single broad elevated dome with a fairly sharp edge. Cheap to cross once you are on it, expensive to climb onto — the case where the terrain factor's insensitivity to altitude pays.
Bands as in Ranges, plus a few isolated peaks. The default, and the least structured of the four.
The mountain ranges count (1–5) sets how many independent range systems there are; under Scattered it also multiplies the number of isolated peaks. One range on a Ranges layout produces a single spine dividing the country in two — often the most interesting map to operate, because it forces a real decision about where to cross.
Why relief charges you twice
The construction multiplier is the visible cost. The second one is easy to miss because it never appears in a quote.
Settlements are placed by scoring every land cell for suitability, and that score punishes exactly what the terrain factor punishes:
- Lowland is rewarded
- Low ground gets a positive score, and it is the largest single positive term in the calculation.
- Upland and mountain are penalised
- Two separate penalties stack as height rises, and the second is large enough to rule out high ground almost entirely.
- Slope is penalised on its own
- Independently of altitude. Steep ground is unattractive even when it is not high — which is the same quantity the terrain factor measures.
So a mountainous country does not merely have expensive roads. It has fewer and smaller places worth connecting, concentrated in whatever lowland exists, with the expensive corridors running between them. Raising mountainousness therefore shrinks your demand base at the same time as it raises your construction bill.
That is a legitimate scenario to choose — it is arguably the most interesting transport problem the generator can produce — but choose it knowingly rather than because the map looked good.
Rivers and vegetation
Neither of these enters a construction quote, which puts them in a different class from relief.
River density
Rivers are drawn where enough drainage accumulates. The control adjusts the threshold: a higher setting requires less accumulated flow, so more of the drainage network becomes a visible river.
The detail worth knowing is that the threshold is scaled by your map's area, so a given density setting represents roughly the same real-world catchment — around 40 km² — whatever size country you generate. A river on a small map and a river on a large one mean the same thing, rather than the setting quietly meaning "more rivers" on big maps. There is also a minimum river length of about 35 km in real terms, so raising density adds rivers rather than fragments.
For operations, rivers matter mainly as crossings and as a settlement preference: the Waterways settlement distribution favours river and inland-water access, so density and distribution interact.
Vegetation lushness
Vegetation is a country-wide moisture bias applied on top of the moisture the terrain generates for itself — drier below the midpoint, wetter above, by up to about ±0.3 on a zero-to-one scale. It changes what the land looks like and what biomes appear; it does not change construction cost, capacity or demand.
Treat it as the aesthetic control it is. If you want a specific look, set it and forget it.
Choosing relief deliberately
- Decide the shape of the problem first. Do you want a country where everything is buildable and the interest is in demand and pricing, or one where geography forces hard choices? That is mountainousness plus layout, not maximum elevation.
- Use maximum elevation as the cost dial. It scales every height difference and therefore the whole terrain multiplier, while leaving the landscape's structure alone.
- One range on a Ranges layout is the sharpest scenario. A single spine with passes creates a genuine crossing decision instead of diffuse expense.
- Remember the second cost. High relief means fewer good settlement sites. If you want mountains and a substantial network to run, compensate with population density.
- Leave vegetation to taste. It is the one setting here with no mechanical consequence.
Common misconceptions
“Building at high altitude is expensive”
Building across changes in altitude is expensive. A flat plateau at 3,000 m costs about the same as a flat plain at sea level; the climb onto it is what you pay for.
“Maximum elevation is just for the numbers on screen”
It is the conversion from relative height to metres, and the terrain factor is measured in metres. Raising it raises construction costs across the whole map.
“I'll tunnel through the mountain”
On the national map, tunnels are an option for water crossings. High ground is priced, not bored through — your lever is the path, not the engineering.
“Mountains only cost me at construction time”
They also cost you at generation time. Steep and high ground is scored down for settlement, so a mountainous map gives you fewer and smaller places to serve.
Continue the collection
Next: the people. How density scales both population and the number of settlements, how places are ranked and spaced across your territory, and why the pattern you generate is the demand map you spend the rest of the game serving.