The Colors of Mars

I can’t quite remember why I started, but for the past several weeks I’ve been thinking on and off about hypsometric tinting schemes for the planet Mars.

There are a wide variety of elevation coloring schemes that exist for the Earth; I won’t get into details here, but most of them start with some sort of green in the low areas and move through some combination of brown/yellow/orange/red until they reach white in high areas. It’s a visual proxy for land cover, though it’s a rather flawed one.

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Typical Earth hypsometric tints, from the Patterson & Jenny Cartographic Perspectives article linked above.

But what we use for the Earth doesn’t entirely 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.

 

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 (though they do certainly look different). They are garish and confusing, and also problematic for any readers who have color vision impairments.

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A rainbow of colors on Mars, by NASA/JPL/USGS

Some Alternatives

Fortunately, there are a (very) few maps out there that take a non-rainbow approach.

Gradients

Let’s meet our contestants!


Kenneth Field’s (Is There) Life on Mars? starts with deep purple in the basin of the Hellas Planitia, and then proceeds through some nice rusty oranges before settling on a sandy tan (though the its context on the map makes it look more yellow).

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Kenneth Field


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.

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Henrik Hargitai


My own scheme, which I’ve never actually used except for in this very blog post, 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.

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Daniel Huffman


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.

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Daniel Macháček


Honorable mention goes to Eleanor Lutz’s Here There Be Robots. It’s a medieval-inspired map, and it uses a a tint scheme that looks to be based on an Earth hypsometric tint scheme. On that account, I didn’t include it above (though it’s a lovely work and you really should check it out).

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 look of Mars, which 3 of the 4 of them are, you’re kind of limited. Mars is much more uniform in color than the Earth.
  • Much of the Mars elevation range is taken up by four giant mountains. Notice in Ken Field’s scheme how little of the map area is tan, and yet that tan covers half of the elevation range of the scheme. Likewise, Hargitai uses a deep red to cover a pretty large chunk of the elevation range.

These are the only non-rainbow Mars schemes I’ve found. You might know of some others, but in any case I was a little surprised at A) how rare they were, and B) the degree of variation among them. By collecting them in one place, perhaps I’ve given any future Mars mappers some inspiration for their efforts.

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