Once the coastline is clearly defined, currents can be determined. I've detailed that process elsewhere, and these are the results for the map we're working with. The blue-white scale indicates the angle of the current in each cell from 0 to 360. There's probably a better way I can show this but for now this'll do.
This algorithm takes a really long time to run, so I think I'll accept these results as is, unless some hidden issue rears its head along the line.
Continuing on with the work of generating terrain from the tectonics. My first fresh crack uses both tectonic uplift and droplet erosion. These processes are cycled over and over until some condition is met. In this case, I start from a flat plane and stop when at least one cell is at its maximum height (25599 ft). The sea level is determined such that 29% of the total surface is land. I also apply a hypsometric curve to the land area so that higher elevations appear in roughly the same proportions that they do on our earth.
However, this algorithm generates a pretty boring topography. The mountains slope up uniformly from the coast, and the tectonic uniquenesses are not presevered. Usable, but disappointing.
The problem is that the erosion cycle is too powerful as the terrain grows from zero, and only the center of the continents (that is, the areas with the least erosion) have any chance of growing at all. To fix this, I began with a terrain generated directly from the relative uplift scaled to max height. The warping effects are clearly visible here but these will be smoothed out by the erosion algorithm.
Next, I again cycle through the erosion, but this time I rescale the height at the end of each cycle and apply the same hypsometric distribution. This yields a much more interesting topography.
The grayscale map is a bit hard to parse, so I threw the map into GIMP and applied a simple colormap. where 10,000 ft begins to turn into gray/white.
There are still some issues I can see, or improvements that can be made. Coastal areas are pretty uniformly low for many hexes inland (no Chilean Andes). Most areas do not have significant mountain ranges, although there is one range similar in size to the Tibetian plateau.
But this is the process. Design, test, repeat. This will be good for now and I'll move on to some other elements of the climate system.
In the previous iteration, the tectonic plates were generated from a Voronoi algorithm, and thus had very straight edges. Here, I've made those more jagged, which should result in a more interesting coastal topography.
And it does! There is still a good deal of far-too-straight lines, but we can live with some of that. The ripple algorithm, which I'll tackle next, should help.
A bit of Gaussian blur:
Next, to closer approximate real-world distributions, I'll apply my hypsometric scaling.
Lastly, to get a feel for how this will shake out, I use the uplift values to generate a quick and dirty initial altitude map. The coastlines are a bit blobby, but I'm happy with this part of the process.
Getting the ripple algorithm to work will be my next order of business.
