More Mountains, Islands and Rivers, Oh My!

Very late Thursday, early Friday- I had a bad day… although it really wasn’t so bad, I just zonked out. I did watch ‘Father Brown’, but then I zonked out again. What I did get done was to consider how to make archipelagos at the borders of sea Voronoi Cells, just like we get mountain ranges; archipelagos are just mountain ranges which stick up out of the sea! I also decided that rivers drain river basins so we need to be able to enter and leave VC, but mostly leave. If we enter from another VC, there will be a river pixel bordering the entry and one bordering the exit, unless it’s already ocean pixels. We pick a border pixel for the exit point and can use the feature point of the VC averaged with a random pixel coordinate in the VC for the ‘source’ of the river.

Land, including sea coast and river pixels, is above sea level. Mountain ranges are considerably above sea level, but definitely higher than neighboring non-mountain range pixels. Each point in the river is some little bit above links which are ‘downstream’, so we can map out the course of a river, procedurally, by simply adding a few points between the source and the river mouth, then finding the pixels between those turns or stages, making them successively higher. By definition the land bordering the river course is a little higher, those pixels drain to the river. Thus I can make a map of relative heights and add some random variation as I go along, or later.

I want to be clear here that land and sea pixels, mountain range and archipelago pixels especially but any coasts are just ‘mostly’ coastal land or sea, mountains or islands. This is fractal, especially the coastline at a higher resolution. but this is all, always, going to be work in progress, the highest level of detail we can access globally. I can’t generate a one meter resolution world instantly, and even a 1 km resolution world would be around half a billion pixels, so no, that’s not happening. But we can drill down as we need to, refine our numbers and use PR#s to make sure it’s the same zoomed in map the next time we go there...