cfr42
commented
3 weeks ago ice-to-air/.style={fill/.style={fill=none, top color=ice, bottom color=air},},
fill=none does nothing here.
defines a color gradient, here top to bottom. Is it possible to define a binary step function gradient style where you choose the step location (in % or absolute)? Yes, of course, this is LaTeX.
Not entirely sure what you mean here, but you can create both custom fadings and custom shadings, as well as custom patterns.
Note that there is a difference between patterns and patterns.meta. white hash in example 4 in the sankey manual, for example, uses the latter. patterns.meta is newer and intended to address some of the design problems in patterns in the same way as arrows.meta is intended as an improved replacement for arrows.
You should also look at pgfplots for ideas, though I don't know how well that would cooperate with sankey.
Should display uncertainty graphically.
Hatch
This approach seems unlikely to work with flows and curves - if the flow has a different width curves will be different.
Could possibly use TikZ style? The current style
defines a color gradient, here top to bottom. Is it possible to define a binary step function gradient style where you choose the step location (in % or absolute)? Yes, of course, this is LaTeX.
Shading
It may be easiest to not auto-generate uncertainty. Just do it manually for the publication. Use hatch, dots, or shading. See for example https://www.visualcinnamon.com/portfolio/oecd-global-plastics-outlook/