Currents V: Refresher

Try to avoid SVGs with a quarter million linked objects, if you can.

In the meantime, the currents are looking nice when applied to the generated terrain surface.

I begin with a handful of hexes in the ocean, on the coasts where the trade winds are blowing more or less perpendicularly into the ocean. I then propagate this current forward (curving around the map folds). When the current reaches an opposite coast, it curves back around.

The next step is to fill in all the gaps using IDW (with nearest neighbor distance $k=20$ and exponent $n=2$), which I've used quite commonly in the past for many applications. It's a really useful little algorithm. This generates a smooth fill.

Lastly, I apply a Gaussian filter to smooth out the sharp bits even more.

This has proven more than adequate for my needs, especially concerning the influence of cold and warm coastal currents, as well as trade and migration routes further down the line. The possibilities present themselves endlessly.