An interactive atlas of changing coastlines

The Archipelago
Machine

Raise the sea. Watch continents become islands, islands become fragments, and entire landscapes disappear. Every coastline is a moving mathematical boundary.

Atlas no. 011 / Imaginary seas
Hydrographic survey · unnamed ocean
36° N · 14° E
N
SeaLowlandsHighlands
Click an island to explore ⟶

Command the tide

Sea level71 m
Low tide · 44 mHigh tide · 104 m
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Islands
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Dry land
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Coastline, km

The fragmentation curve

Number of islands at every sea level. Peaks mark moments of maximal fragmentation.

Expedition log
Uncharted shores

Select a landmass on the map. Each island has a name, a highest point, and a story that survives only while the island does.

No island selected

A surprising fact about rising seas

Increasing the water level always decreases the amount of land, but it need not decrease the number of islands. A narrow land bridge can drown and split one island into two. Keep raising the water and those islands vanish as well. This is a small, visible example of topological change—a landscape losing area while temporarily gaining connected components.

A fictional landscape with actual connected-component calculations. Built as a self-contained, offline-capable experiment. Cartography is invented; the topology is real.