For a plot I want to represent two periodic angles with a single color. Theoretically this is possible, since a torus (think Doughnut, any surface point of which can be described via two angles) can be embedded into the RGB cube. My question is though, has someone already come up with a colorspace such that for a fixed third coordinate it is highly unlikely to mistake one combination of two angles for another one?
For visualization, here’s the Wikipedia image from Toroidal coordinates
One angle φ describes the yellow plane’s orientation, the other angle would be the polar angle on the circle from the intersection of that yellow plane with the blue torus. (Please ignore the red sphere which is for another coordinate (σ) that is not periodic.)
Humans as a general rule can not remember associations individual colors very well. As far as most humans are concerned its like there are about 6 to 10 colors only. Which those colors are and what they are called is another thing altogether (for a humorous nerdm scientific look at the subject see XKCD color survey results).
That said humans are good at spotting color differences if you have the colors side by side. This means that if you have a 2 to 3 color gradient then humans can spot more or less the weight correctly just as long as either the scales are visible or theres enough samples to compare. So since you in fact have a 2d space you could try to use a four corner gradient for the job.
Just remember people need their memory jogged as to what that means.