Wondering about the best approach for applying elevation color layers in maps

[BillSiever]

Hello all,

I'm newish to Illustrator and am wondering about the best approach for applying color layers for the different elevations in maps. I've attached two screenshots: the first is an example of what I want to do (from https://gisgeography.com/wp-content/uploads/2020/07/US-Elevation-Map.jpg), showing the US Northwest; the second is my map in progress, with a few labels and the colors exaggerated for illustration purposes.

Here's what I've done so far:

-- Added the contour lines (the thin brown lines).

-- Connected the lines off the map so that I could then create a full shape that I could fill with a color. For example, Line X is above (outside) the map, and it connects the contour lines on the left and right sides of Shape C so that I could fill Shape C with the green color. The problem is that Shape A, which is supposed to be the same color as Shape B because they're the same elevation, is now a different color because the colors are all set at 50% opacity. (I'll probably eventually go with 10% opacity: I want the colors to be very subtle.)

So this brings up a few questions:

-- Rather than using 50% opacity, should I just make the colors themselves more pale, so that I could then set them at 100% opacity? That way, Shapes A and B would look the same, since you wouldn't see the color from Shape C underneath A.

-- I think I just answered my own question, but I would appreciate hearing back from someone who knows about this stuff. For instance, should I be using masks or something like that? I don't know how to use those yet, but I could learn.

-- So if I do go with pale, 100% opaque colors, then I'm thinking I would set the layers up so that the lowest elevation would be on the bottom layer in Illustrator, with the higher elevations subsequently hiding the ones below. And then I would have all the contour lines, roads, trails, etc. on top of those layers (which I already have set up in layers). Does that sound about right?

Thanks in advance for any advice!

-- Bill

[BillSiever]

Just as a follow-up, if I do decide to make the colors more pale and 100% opaque, could someone suggest an easy way to do that consistently? I'm just learning about color swatches and libraries, so some guideance would be much appreciated.

-- Bill

[Doug A Roberts]

I would probably create a single global colour swatch, and use various tints of it for the levels. That way if you change your mind, you can change everything at once.

[BillSiever]

Thanks for the reply! I will wait to see if anyone else chimes in, and then I'll investigate that option. At the moment I'm not entirely sure what that means, but I will investigate. Thanks!

-- Bill

[Doug A Roberts]

These are tints of the same swatch at 100% opacity:

If I want to change them, I edit the global swatch definition.

[BillSiever]

Ah, I see, very cool -- thanks!

-- Bill