Terrain Taxonomy and Geographic Tags

Package provenance — this chapter ships with the Ontology & Structure Engine. Provenance tag: source-ontology-project. When loaded into a new world, grep the tag to find the engine's templates and instructions.

What this is

A system-level classification for the ground every adventure stands on. Terrain files in /Terrains/ are the reference list — one file per terrain class, each carrying its classification axes, canonical tags, real-world and fiction exemplars, and sources. Regions and Locations attach to that list two ways: Terrain references (which terrain files a place is) and terrainTags (the canonical tag vocabulary that makes retrieval consistent). This chapter is the index and the rulebook; the files are the content.

Why a taxonomy instead of free text

Geography is the stage all other knowledge stands on, and retrieval only works if "marsh," "fen," "swamp," and "bog" do not fragment into four unrelated concepts. The schema enforces the vocabulary: terrain on Region and Location is a reference field (it must point at a Terrain file), and every terrainTags entry must match the pattern ^(realm|medium|elev|climate|habitation|terrain|water|edge)\.[a-z0-9-]+$. Free recall tags (frontier, haunted, trade-hub) still belong in the ordinary tags field — terrainTags is reserved for classification, tags for recall.

The classification axes

Seven axes, each with a tag prefix. Every Terrain file sets its axes; Regions and Locations copy the relevant tags.

1. Realm — reality class (realm.) — physical (the ordinary world), planar (a plane or dimension with its own rules), pseudoreal (dream, memory, or impossible space that behaves like place). A dreamscape is not a "strange swamp"; it is a pseudoreal terrain with liminal medium.
2. Medium — the milieu (medium.) — terrestrial, aquatic, subterranean, aerial, liminal (threshold states). A terrain can span two, primary first (marsh = terrestrial + aquatic).
3. Elevation — vertical position (elev.) — subterranean, coastal, lowland, upland, highland, alpine, aerial, depth (marine depth classes).
4. Climate — weather regime (climate.) — polar, boreal, temperate, maritime, mediterranean, arid, tropical, equatorial, alpine, constant (caves, deep sea). Köppen-derived so real and fantasy worlds share one scale.
5. Habitation — settlement pressure (habitation.) — inhabited, sparse, uninhabited, abandoned. Terrain files carry the class tendency; Regions and Locations carry their own habitation field (the actual state), and the instance wins.
6. Terrain type — the named landform (terrain.) — the biome list in the vocabulary below. Primary classifier.
7. Refinements — water. (fresh / salt / brackish / still / running / ice) and edge. (ecotone — gradual blend; interface — hard boundary, e.g. a coastline or planar threshold).

The canonical tag vocabulary

Use only these values. terrain.* may grow as new Terrain files are created; the other prefixes are closed vocabularies.

realm.physical  realm.planar  realm.pseudoreal
medium.terrestrial  medium.aquatic  medium.subterranean  medium.aerial  medium.liminal
elev.subterranean  elev.coastal  elev.lowland  elev.upland  elev.highland  elev.alpine  elev.aerial  elev.depth
climate.polar  climate.boreal  climate.temperate  climate.maritime  climate.mediterranean
climate.arid  climate.tropical  climate.equatorial  climate.alpine  climate.constant
habitation.inhabited  habitation.sparse  habitation.uninhabited  habitation.abandoned
terrain.wetland  terrain.marsh  terrain.swamp  terrain.bog  terrain.fen  terrain.floodplain
terrain.river  terrain.lake  terrain.coast  terrain.island  terrain.forest  terrain.woodland
terrain.rainforest  terrain.jungle  terrain.taiga  terrain.grassland  terrain.steppe
terrain.savanna  terrain.prairie  terrain.desert  terrain.sand-sea  terrain.salt-flat
terrain.badlands  terrain.canyon  terrain.plateau  terrain.mountain  terrain.hill
terrain.tundra  terrain.glacier  terrain.ice-shelf  terrain.ocean  terrain.sea  terrain.reef
terrain.abyss  terrain.trench  terrain.cave  terrain.cavern  terrain.underground-sea
terrain.fungal-forest  terrain.volcanic  terrain.wasteland  terrain.blighted  terrain.ruin
terrain.urban  terrain.cloud-sea  terrain.dreamscape  terrain.planar
water.fresh  water.salt  water.brackish  water.still  water.running  water.ice
edge.ecotone  edge.interface

Attaching tags to regions and locations

Both Region and Location carry three classification fields:

• terrain — array of Terrain references, primary first. Use one for the dominant terrain; add more only when genuinely mixed.
• terrainTags — copy the referenced Terrain files' tags, pruned and extended for the specific place. Pattern-enforced by the schema.
• habitation — the actual state of this place, even when it differs from the terrain's tendency.

Example — Mistveil-region:

{
  "terrain": ["marsh-terrain"],
  "terrainTags": [
    "terrain.marsh", "terrain.wetland", "water.fresh", "water.still",
    "elev.lowland", "elev.coastal", "realm.physical",
    "climate.temperate", "climate.maritime", "habitation.sparse"
  ],
  "habitation": "sparsely-inhabited"
}

The terrain index

Seventeen reference files currently live in /Terrains/. Each lists characteristics, typicalFeatures, real-world and fiction canonicalExamples, and sources — read the file for the depth; this table is the recall surface.

Where the taxonomy comes from

• Real-world geography: the Köppen climate classification; Whittaker and Holdridge biome schemes; Cowardin wetland classes (USFWS) and the Ramsar wetland types; marine depth zones; fluvial and aeolian landform vocabulary.
• Fiction and myth: the Underdark, Moria, Journey to the Center of the Earth; planar cosmology and afterlives from a dozen legends; the Dreaming, the Fade, dreams brought to matter; clouds and skyfloat worlds; sunless seas; drowned abysses.

None of it is binding — a world without planes never uses realm.planar. The enums exist so retrieval has one stable vocabulary instead of fifteen spellings of "swamp."

Rules of thumb

1. Reference the Terrain file for the dominant terrain; use terrainTags for the rest of the classification.
2. Copy tags from the Terrain file — do not invent new terrain.* spellings. If a genuine new terrain exists, create a file in /Terrains/ and update this chapter's index.
3. habitation on the Region/Location is truth; the Terrain file's tendency is a prior.
4. Never restate a fact a Terrain file owns — link it instead.
5. World-specific color (blighted, haunted, tidelocked) goes in the free tags field, not terrainTags.