Strategic route terrain

World schema v25 and inference rules v9 attach a required RouteTerrain to every imported travel edge. The record is a static strategic fact used for travel planning and encounter selection. It never persists tactical positions, damage, HP, enemies, or simulation ticks.

Weather is a calculation-only overlay over this immutable package. Version 1 uses coarse quarter-degree cells and six-hour absolute-time intervals. Route cells use their own imported elevation and wetland facts; settlement soil or hydrology is never projected onto arbitrary cells. Departure route payloads attest the weather rules version, aligned interval, condition, intensity, antecedent moisture, and snow cover. Validation rejects unbounded or inconsistent snapshots, and the gateway cache distinguishes them. Route search, duration, persisted span weights, and check_millirank all use the same departure overlay; weather is not a post-processing adjustment.

Rain only increases effective Wetlands when the imported normalized weight is at least 100/1000. Displaced weights are deterministically renormalized to keep the five-member total at 1000. Independent saturation severity allows a 1000/1000 wetland to become slower without corrupting the mixture.

Geometry and elevation

Viabundus supplies topology and endpoint coordinates rather than complete road polylines. Documented edges therefore retain the endpoint interpolation below. Terrain-inferred edges instead sample their canonical A* polyline. The compiler chooses N = min(1000, max(1, ceil(length / grid-cell-size))) segments, yielding a bounded profile of two through 1,001 samples with unique permille progress and required 0/1000 endpoints.

Each profile point samples GLO-30 at the center and the eight positions one configured canonical-grid cell away. The shared strict reader validates tile georeferences and handles nodata consistently with settlement elevation. Decoded tiles use a deterministic least-recently-used cache bounded to 64 MiB; eviction changes memory use only, never sample values or artifact identity. Missing tiles and terminal voids use the explicit sea-level fallback; the build report and edge Markdown record that choice.

Consecutive center samples produce ascent, descent, and signed maximum grades. Interior projected coordinates use sign-symmetric nearest-integer rounding, so reversing an edge yields the exact reversed coordinate sequence. The 3x3 neighborhoods produce Horn slope/aspect, mean absolute center-neighbor difference (TRI), and relief. Aspect is Flat below 10 permille mean slope; otherwise a circular mean selects one of eight closed compass directions.

Rules v6 classify a route as:

• Flat: maximum slope below 30 permille and relief below 30 m.
• Rolling: below 80 permille and 100 m.
• Hilly: below 150 permille and 300 m.
• Mountainous: everything else.

A center at least 20 m above/below its eight-neighbor mean marks a ridge or valley. A likely pass requires opposing high neighbors and lower orthogonal neighbors. Adjacent identical detections are deduplicated deterministically.

Water, seasons, and encounters

EU-Hydro crossings and ferry waterways become canonical nearest facts at zero meters. Feature kinds are river, canal, ditch, inland, tidal, and coastal. Seasonal rules are deliberately small and exact: ford/ferry facts dominate spring flood, autumn mud, and winter ice severity; nearby freshwater can add low mud or ice risk; mountainous or 1,000 m routes add medium winter snow. No summer-drought route rule exists in v5.

Static encounter tags cover terrain class, steep (at least 150 permille), rough (TRI at least 20 m), landforms, bridge/ford/ferry, water banks/shores, and each seasonal hazard. Empty collections mean confirmed absence, never unknown. Viabundus slope_multiplier remains a separate source cost hint and is not DEM grade.

Both the offline validator and strategic import reducer recompute profile ascent/descent, grade extrema, relief, class, seasonal risks, and encounter tags. Malformed or contradictory derived facts are rejected. Collection decoding is capped before allocation and canonical uniqueness is defined by logical key (progress, feature, hazard, or tag), not by the complete payload.

The official full GLO-30 and EU-Hydro audit remains blocked until their authenticated, completely pinned source inventories are available locally. Synthetic tests exercise deterministic algorithms and strict boundaries; this document does not claim issue #62 complete.

Native routing skill mixture

The separate native terrain-routing pack (schema 6) retains wetland, canopy, and hill coverage independently. Runtime routing cells normalize them to exactly 1,000 permille: Wetlands receives its area share first, Forest follows canopy density over the remaining land, Hills receives the hill-covered share of the remaining non-forest ground, and Plains receives the remainder. Urban is part of the Terrain skill domain but has zero route weight until an authoritative built-up-land source is added; roads are infrastructure over their underlying terrain and are never treated as Urban.

Plains, Forest, Hills, Wetlands, and Urban are intuitive mental checks governed by Intelligence on the shared rank-zero-to-five curve. Party checks use bounded party aggregation, then the cell mixture's dot product. Movement speed is multiplied by 1 + check / 10. The departure profile is in the A* cache key and the resulting adjusted spans are validated and persisted, so skill can affect route choice while an active journey remains stable.

Actual walking trains every living traveler and conserves exposure across the normalized mixture. Non-road movement grants one exposure hour per movement hour. Roads still train their underlying terrain, discounted by underlying off-road speed divided by 5 km/h: 0.25 open, 0.20 sparse woods, and 0.15 deep woods. Camp intervals grant no Terrain training. Wetland road exposure is 0.10, from 0.5 km/h divided by 5 km/h.

terrain-routing-base-v3 is a documented-road-only inference input and cannot be served as the final pack. terrain-routing-v3 is rebuilt after world compilation with the accepted inferred polylines. Both manifests carry a purpose, road-geometry digest, Jung wetland source digest, and package digest. Wetland ground moves at 0.5 km/h unless overridden by water or a road. Schema 6 uses one flag bit for the canonical EPSG:3035 1 km cultivation classification and another for native wetland coverage, so cells remain five bytes. Both bits decode to area fractions when cells are coarsened. The manifest validates the grid CRS/resolution, HYDE dependency digest, allocator rules version, and square/native-cell counts. Runtime sampling is bounded by the existing chunk LRU.