Nested EarthA RECURSIVE ISLAND ATLAS
OSM SHORELINE SURVEY
Canadian Arctic · Canada
Island layers —

Counts in this survey, by observed order.

Check a layer to show its islands. Orders can be lower bounds.
Island Lake

Loading the island chain…

THE ISLAND INSIDE THE ISLAND

Island orders, explained.

Every new lake with an island adds one order.
Count the islands, not the shorelines.

01 / FIRST ORDER

An island.

Land completely surrounded by water, in a lake or the sea. This is the outermost island in the chain.

Water → island 1
02 / SECOND ORDER

An island on an island.

A lake sits on a 1st-order island. An island inside that lake is a 2nd-order island.

Island 1 → lake → island 2
03 / THIRD ORDER

One layer deeper.

A 2nd-order island has its own lake, and that lake has another island. That innermost land is 3rd order.

Island 2 → lake → island 3
04 / FOURTH ORDER

Inside the third.

An island in a lake on a 3rd-order island. Four islands nest inside one another, with water between each level.

Island 3 → lake → island 4
Not found in these surveys
05 / FIFTH ORDER

And another island.

An island in a lake on a 4th-order island. A fifth land level requires another complete enclosing lake.

Island 4 → lake → island 5
Not found in these surveys

Our counting convention: the outermost island is order 1. Diagrams illustrate the pattern; they are not real discovered places. Land is cream, water is gray, and pink marks the innermost island.

“At least” means the view may be incomplete. OSM can omit an enclosing shoreline or a tiny island. No result at a given order means none in the loaded survey—not that none exist on Earth.

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WELCOME TO NESTED EARTH

Islands inside islands.

One island. A lake on that island. Another island in that lake.
Each new island adds one order.

These diagrams explain the pattern. The map counts real OSM islands in each loaded survey. Missing outer shorelines can make an order a lower bound; 4th and 5th order are not confirmed in our bundled surveys.

 A LITTLE GEOGRAPHIC RECURSION

One more lake.
One more island.

We count the outermost island as 1st order, whether it sits in the sea or in a lake. An island in a lake on that island is 2nd order. Repeat for 3rd, 4th, 5th… there is no detector depth limit.

Island 1 Lake Island 2 Lake Island 3

Geometry-backed means each step uses closed OSM shorelines. A water polygon’s hole supplies an island boundary. A contained lake leads to the next island. Crossing, touching, incomplete, and invalid rings are excluded.

“At least” is deliberate. Area scans can miss enclosing lakes or coastlines. Only a chain reaching a complete mapped ocean-island coastline is marked coast-anchored. Other orders are lower bounds. A 1st-order lake island on the mainland can still have an unanchored result.

Scans cover the visible area, up to 1,500 km², and run only when requested. Bundled surveys are OSM snapshots, not a worldwide census. “No 5th-order results” means none in the loaded data; it does not prove none exist. Tiny, seasonal, tidal, artificial, or unmapped features may change results. Open coastlines and antimeridian polygons need a separate global coastline pipeline.

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