A probabilistic cellular automaton that models urban expansion. Watch a city grow from a commercial core: empty cells become residential, dense residential upgrades to commercial, and the built-up area sprawls outward.
Growth on a CA grid driven by proximity rules: empty cells near existing development have a higher chance of becoming residential; residential cells surrounded by dense neighbours upgrade to commercial. The result resembles real urban sprawl patterns.
Adjust the growth probability and densification rate. Click reset to start from a single commercial seed. Watch the concentric ring pattern emerge — commercial core, dense residential, then sparse outskirts.
Urban cellular automata were proposed by Michael Batty in the 1990s. The concentric zone model matches Burgess's urban ecology theory (1925), where cities grow outward from a central business district.