Add a gravity link only when the network path is at least this many times the straight distance.
Build networks at all.
Extra road links beyond the spanning tree, as a fraction of the settlement count (gravity model).
Distance exponent of the gravity model (interaction = P₁·P₂ / dᵏ).
Both ends at least this populous: highway.
Nearest settlements considered for gravity links, per settlement.
Settlements at least this populous get power lines (0 = none).
Settlements at least this populous get a railway (0 = no rail).
Extra cost per unit slope² for railways (rail hates hills).
Cost multiplier on cells an earlier route already uses, so roads merge into trunks (1 = off).
Both ends at least this populous: road (else track).
Extra cost per unit slope² for roads (cost = length × (1 + slopeCost × slope²)).
Chaikin smoothing passes on routed polylines.
Cost multiplier for crossing water (bridges).
How settlements and people are connected (see
generateNetworks).