Lab / 02

Denmark needs fifteen machines

Norway gets one Fourier series. Denmark is a peninsula and a pile of islands, so it gets 15 separate chains of spinning arms, all hanging off the same hub in the Kattegat-ish middle of the country and all drawing at the same time. Jutland does the heavy lifting. Anholt does very little, but it does it beautifully.

One series per landmass

A Fourier series is a single closed loop, so every island needs its own. Each outline is sampled as evenly spaced points, turned into complex numbers, and run through a discrete Fourier transform. The coefficients become arms, sorted longest first.

zisland(t) = Σ ck · e2πikt

The first arm of every chain is the long straight one from the hub to the middle of that island. That is why the drawing looks like a starburst before any coast appears. Small islands only have 64 sample points, so they top out at 64 arms - turn N up and Jutland keeps improving while Fanø is already done.

Which islands

This map knows fifteen landmasses.

Denmark has more than 400 named islands. The 1:10m world map used here only knows these fifteen - Falster is not on it at all, and most of the South Funen archipelago is missing. Which is a nice lead-in to the coastline paradox: how much Denmark there is depends on how closely you look.

Outline data: Natural Earth 1:10m (public domain). Source on GitHub