Tutorial 03 Climate and biomes

Part of the tutorial: page 3 of 12

▶ Watch this page: part 3 of the tutorial video (about 1 min), with narration and subtitles.

Tutorial 3: Climate and biomes

See how the biomes are worked out from the climate, add a biome of your own with a rule for where it grows, and paint it by hand.

Start from: 02-shaping-the-land.json, the map as it is at the end of Tutorial 02 Shaping the land. Download it, then open Maps on the rail and click Import JSON; the map is listed under its name, and Load opens it. Or carry on with your own map from Tutorial 02 Shaping the land.

The module works out a biome for every point of the map from four things: its height, how wet it is, how warm it is, and the latitude. Moisture follows the prevailing winds, so mountains cast rain shadows; temperature falls with latitude and with height. The Biomes tool sets the climate these come from, and lets you add biomes of your own.

Steps

1. Click Biomes on the rail, the third tool in the Shape group. Climate and Moisture hold the settings the biomes are worked out from: the whole world's temperature and moisture, the season, how fast it cools with height and when water freezes. The tutorial map keeps them as they are.

   

   The Biomes tool, with the Climate and Moisture sections.

2. Point at the land in the north-east of the continent. The information bar at the top left of the map shows the point's Elevation, Moisture and Temperature, each as a percentage, and the Biome they give: here, high, very dry, warm ground, so desert. Move around to see how they change: the land is cooler further north and higher up, and drier in the lee of hills.

   

   The information bar reads the point under the pointer.

3. Open the Edit biomes section and click Add custom biome (the + beside Custom biomes). In the dialogue, name it Moorland, set its Colour to #8c7a8a (a heather mauve) and leave Placement at Land only and Behaves like at The biome beneath.

   

   The custom biome dialogue for Moorland.

   Behaves like tells Generate how to treat the biome's land, for farming, travel and cover. The biome beneath treats moorland as whatever the climate would give there.

4. Click Confirm. Moorland is listed under Custom biomes. It has no rules yet, so it only appears where you paint it.

5. Click Biome rule editor, then + Add rule on Moorland's row. A rule has three tracks, Elevation, Moisture and Temperature, from 0 to 1 (the information bar's 58% is 0.58 here), and the biome appears wherever a point falls inside all three ranges. Click Upland under the Elevation track, then drag the right-hand handle of Moisture to 0.45 and the right-hand handle of Temperature to 0.50: moorland grows on cool, fairly dry uplands.

   

   Moorland's rule: uplands, moisture up to 0.45, temperature up to 0.50.

   Rules run from the top: the first whose ranges all match a point wins, and the built-in biomes, listed below yours, catch every point no rule matches.

6. Click Accept. The biomes are worked out again, and moorland appears on the cool, dry uplands in the north of the continent.

   

   Moorland on the northern uplands.

7. Now paint it where the rule does not reach. Click Start painting, choose Moorland in Select biome on the bar, and set Size to 10 px. Zoom in on the island to the east and paint a few short strokes along the top of the ridge you raised on page 2.

   

   Moorland painted on the crest of the island's ridge.

   The biome brush paints its whole circle at once and only where a biome's placement allows: a land biome only on land. Erase on the bar takes a painted biome away again.

8. Click Stop painting, then Save map on the rail.

What you should see

Mauve moorland on the cool, dry uplands in the north of the continent, and along the ridge of the island to the east. The rest of the map's biomes are as they were.

To compare your map with the tutorial's, or to start the next page from exactly this map, download 03-climate-and-biomes.json and import it in Maps with Import JSON.

In Foundry

Everything on this page is the same in Foundry.

On your own map

Settle the climate before you add your own biomes: Global temperature and Global moisture move every biome at once, and a custom biome's rule is matched against them. Use Preview rule coverage (the eye beside Biome rule editor) to see where your map still falls back on the built-in biomes. A custom biome's Code is carried into the exported grid data (see Grid Cell Data), and Styles and icons shares custom biomes between maps. See Biomes for the rule editor in full.

Next: Tutorial 04 Rivers and faults

Related: Biomes, Terrain, Styles and icons