CIVIL_SYSTEMS
HexPlan · Community planning · 25-year scenarios

Plan the pattern.
Explore the consequences.

HexPlan is a community-planning simulation. You set a direction for growth, preservation, and investment; the model lets local conditions, neighboring places, and uncertainty turn that direction into a range of plausible 25-year futures.

A planning model, not a crystal ball

HexPlan does not claim to forecast one inevitable future. It makes assumptions visible, then helps you see how those assumptions can compound across a community. The useful question is not “what will happen?” but “what patterns become likely if we choose this direction?”

Interactive model · Set a policy directionScenario 01 / synthetic metro

Choose one planning direction

Or set each policy position

Raises or lowers the baseline chance that a place advances.

LowMediumHigh

Rewards locations already connected to the central urban core.

OutwardBalancedCore-first

Adds friction to changing lower-intensity contexts.

LightModerateStrong
Year 0initial context
Rural
Town
Suburban
Urban
Core
Urban + Core0%
Rural conserved0%
Compactness0%
Autoplay begins shortly. Pause anytime, or run the full uncertainty ensemble.
01 / The engine

Three ingredients, one yearly transition.

The model tests each hex every year. A location can stay as it is or advance one context step. It does not leap across the map, and its future depends on the surrounding system.

1 / Local potential

What is around it?

Nearby higher-intensity places, access to the core, and local suitability create a bounded transition potential for each hex.

2 / Time & policy

How much change is allowed?

Development has inertia. Policy can pace or resist change by context, especially in rural and town areas.

3 / Plausible futures

What happens this run?

The transition is sampled, so small differences can accumulate. Repeat runs reveal a range of plausible planning outcomes.

The spatial signal

A logistic function keeps the local transition potential bounded between 0 and 1 while allowing the scenario weights to express different planning hypotheses.

P* = σ(β₀ + βₙNₕ + βₐAₕ + βₛSₕ)
The yearly decision

That local potential is then tempered by time since the last change and a context-specific policy gate. The result is sampled once for every hex, every year.

P(advance) = P* × (1 − e−t/τ) × Fcontext

For the uncertainty map: 100 runs produce a final-state distribution for each hex. Normalized Shannon entropy shows where those plausible futures disagree most.

H = −Σ p(state) log₂ p(state) / log₂(5)
02 / Planning judgment

The outcome is a conversation starter.

Use HexPlan to surface trade-offs early: where to concentrate investment, which contexts to protect, and where uncertainty deserves more investigation before a long-range commitment.

Compare strategies, not just maps

Run the same community under a few policy directions. The differences reveal which assumptions truly shape the pattern.

Read the edges carefully

Areas that vary most across runs are not errors. They are places where future context is sensitive to the choices and conditions in the scenario.

Bring infrastructure into the picture

Context change alters the demand, exposure, and operating conditions that transportation, water, energy, and public systems must serve.

Keep uncertainty in view

The simulation is designed for exploratory planning. It supports better questions under deep uncertainty; it does not erase the need for local evidence and judgment.

The model illustrated here is a simplified, approachable interpretation of the HexPlan spatial Markov framework: hexagonal context units, neighborhood influence, accessibility, suitability, persistence, policy friction, and stochastic scenario simulation.

See where a community's future could go.

Use HexPlan to try a planning direction, see the spatial pattern it encourages, and have a more concrete conversation about the choices in front of a community.