Note that this post has been superseded by a more complete, ongoing inventory: An Inventory of Martian Hypsometric Tints.
I have a peculiar and growing hobby of collecting Martian hypsometric tinting schemes: those sets of colors that cartographers use to depict elevations on the Red Planet.
Unfortunately, the great majority of Mars maps that I have seen use a rainbow scheme for their hypsometric tints, which make a mess of everything. They are garish and confusing, and also problematic for any readers who have color vision impairments.
However, there are a few cartographers that have taken the time to craft some more interesting and attractive alternatives. Below, I present all the Mars hypsometric tinting schemes that I know of (that aren’t rainbows or, with one exception, rehashes of Earth-style hypsometric tints).
Important note: I grabbed each of these schemes from the authors’ original maps (which you can visit by clicking each image), and then applied them to my own map so that they could be compared easily. There may be some slight variations based on how accurately I was able to sample colors. Most maps gave a legend with the colors used, but I often found that they didn’t quite match the colors on the map, usually due to modulation by shaded relief. So I instead reconstructed schemes based on the final appearance, not the map legend.
Daniel P. Huffman, 2017
Rationale
Before I get into these schemes in more detail, a question: why collect and look at these?
On Earth, elevation is generally shown with a color scheme that starts with green lowlands, and then proceeds through some combination of brown/yellow/orange/red until it reaches white in the highest areas. It’s a flawed visual proxy for land cover, though one that’s well-understood.
But what we use for the Earth doesn’t make sense on Mars: its mountains are not snowy, nor are its valleys green (of course, we often tint desert valleys green on Earth maps). Setting aside the idea of these colors mimicking land cover, Mars is a vastly different place, and so it feels wrong to me if it doesn’t look different than Earth. So, I’m very interested in how mappers are approaching Martian elevations. Right now, it’s a sort of cartographic frontier, and I want to document it in its early stages. Centuries from now, we all may settle on a standard of some sort, as we have with Earth.
So, now that we’ve dispensed with the question of why, let’s meet our contestants! You can click on each image below to view a larger version.
The Schemes
Carl Churchill’s map, Mars, starts with a dark grey in the far depths of the Hellas Planitia, which then picks up some saturation to become a dark purple that covers much of the north. It moves from blood red through the oranges, before finishing with a pale yellow (which looks almost like an off-white) at the tops of the peaks of Olympus Mons and the Tharsis Montes. Of all the schemes featured here, this is one of the ones that uses the biggest chunk of the color space.
The scheme from Kenneth Field’s (Is There) Life on Mars? looks at first like a less saturated version of Churchill’s. It starts with deep purple in the Hellas Planitia, and then proceeds through some nice rusty oranges before settling on a sandy tan (though its context on the map makes it look more yellow). The upper half of the scheme is basically a single color. In Field’s original map, details at the high end are distinguished by contour lines and relief shading, so the clipping seen here isn’t a problem.
Henrik Hargitai’s Mars map for Country Movers takes an unusual approach, in that it is at its brightest in the low areas, starting with yellow and turning deep red as elevation increases, and finally finishing off with a little dark pink highlight on the tops of Olympus Mons and the Tharsis Montes.
My own scheme, which I made exclusively for this inventory, is inspired by the colors on the surface of Mars. Due to atmospheric effects, the Red Planet is actually mostly red only if you’re looking at it from space. It’s more brown & tan on the surface, at least if the photos from Curiosity are any indication. I did make the low areas a little reddish just to contrast with the yellow highlands.
Eleanor Lutz’s take on Mars leans heavily on the “Red” in Red Planet. Starting from a blood red in the depths of Hellas Planitia, she keeps things bold and saturated through the lowlands of the Northern Hemisphere, before moving to warm grey for the highlands. It really highlights the contrast of the planet’s two halves, and the upper half of the scheme recalls Earth-based hypsometric tints, in which grey is likewise reserved for the highest elevations.
Finally, Daniel Macháček’s Topographic Map of Mars takes things in another direction; avoiding the Red Planet stereotype, he opts for blue (and a bit of purple) in the lowlands, moving through grey into a cool brown for the higher elevations. It’s a diverging color scheme, starting dark, getting lighter near the middle elevations, and then getting dark again at the mountains (including an interesting band of greenish brown, just below the mountaintops). It highlights the extremes in this way.
Tanaka et al. include a map of Martian hypsometry in the lower right corner of their Geologic Map of Mars. Their color scheme appears to be a simplified version of one you might apply to the Earth, with vegetated green lowlands and barren brown uplands. I mostly want this site to focus on representations of Mars that don’t look back too much to the Earth, but I thought it was good to keep an example of one of these schemes. It’s certainly possible that, centuries from now, cartographers will decide to use the same green–brown scheme for all planets. Note that, like Field’s scheme above, the upper half of the range is all a single color, so that color transitions can be focused on the elevation range that covers 95% of the planet’s area.
Other Observations
- All of these schemes do a good job of highlighting the Martian dichotomy — basically, the northern hemisphere is a few kilometers lower than the southern hemisphere.
- One good thing about a typical Earth hypsometric scheme is that it includes a wide range of colors (greens, yellows, oranges, greys, etc.), which means it can show more detail. The schemes above all cover a narrower color range. But, if you’re going for a color scheme inspired by the actual appearance of Mars, you’re kind of limited. Mars is much more uniform in color than the Earth.
- Much of the Martian elevation range is taken up by a few giant mountains. Notice in Kenneth Field’s scheme how little of the map area is tan, and yet that tan covers the entire upper half of the scheme. Each scheme is marked to show the elevations that cover 95% of the planet, which better reflects most of what’s actually seen in the final map.
These are the only non-rainbow Mars schemes I’ve found. I’m sure others are out there, and I encourage you to send my way any that you find that are: (A) not rainbows, (B) cover all or most of the planet (at least the highest and lowest point), and (C) not based on an Earth-style hypsometric scheme. By collecting them in one place, I hope to document this little mapping frontier, and perhaps give any future Mars mappers some inspiration for their efforts.
somethingaboutmaps 
If you’re concerned about palettes that are amenable to colorblind users (and grayscale printing), the “viridis” collection of palettes (https://cran.r-project.org/web/packages/viridis/vignettes/intro-to-viridis.html) may be helpful. Three of them (“magma”, “plasma”, and “inferno”) would be suitable for the Red Planet theme, and “magma” is particularly robust to all forms of colorblindness.
Thanks! This reminds me that I forgot to discuss color vision impairments in the post (which is something I’m usually very focused on). I look forward to seeing someone’s Mars map that uses one of these.
This is a brilliant idea and long overdue for revisiting. To me the biggest problem about multi hues maps of Mars is that if blue is used for lowlands it gives a false impression of water. There are lots of people who would wish huge oceans existed in Mars and with blue as a lowland color this just seems to reinforce the prejudice.
Whether there was a lot of water once is actually still an open debate
Well done for this initiative!