Watersheds visualized

Am I just reinventing GIS software now?

I spent quite some time refactoring the drainage so that lakes could be known map entities such that they could be given names, and as part of that I captured watershed information.

I’m hoping watersheds will help biome boundaries in the game to feel more natural and well situated in the landscape, though watersheds won’t be the only thing determining biomes.

This is the first time I’m seeing what they look like, and it’s almost like I imagined - many small ones near the coast, much larger ones inland etc., but there are some surprises - cells dotted around the place that aren’t in any watershed, perhaps these are the tiny lakes and sinks that don’t meet my rendering threshold for a lake and are too small to have information such as their watershed stored about them - I store the largest x lakes and watersheds of each continent, where x is currently 1024.

I’ve also seen rivers cross into neighboring watersheds, not sure what’s going on there.

And one showing whole game continents: