I am trying to create a selection of scales for graphs (called "Maps" in our terminology). The scales have two aspects: there is a color key (what range of colors to use), and there is a step size (how do we map a range of values to each color). Each color key may support one or more different step sizes. As we need to make this choice for four graphs independently in a single dialog, I'm trying to keep this compact.
To give some context, the current color key selection looks like this:
Note that the unit domain only changes the units for the top two maps, the others have a fixed unit. Currently, we do not have many variants for the keys, so the list is manageable in size. The item that does have variants just has them included in the list directly. However, as we are adding variants for all but one item in the list, we think that this solution no longer works. We would end up with four entries for most of the scales.
What the options presented are depends on the graph and the chosen unit domain (Diopter or millimeter), but lets focus on the selection of the color scale and its step size for now.
The range of options we need to start offering looks like this (for the maps in Diopters, it will be a bit different for maps in millimeters):
So, what would be a good way to handle such an item/subitem selection in a nice way? Something that is intuitive to use, but does not take too much space or effort... I have already played around with some mockups for different solutions, but as I don't want to steer or influence your suggestions, I won't post them (just now).