Though maps have historically covered large areas, with crewed lunar missions on the horizon and other missions across the solar system in the planning stages, large-scale, small-area maps are starting to steal the limelight. These large-scale, small-area maps provide highly detailed views of the surface and allow scientists to investigate complex geologic relationships both on and beneath the surface. These types of maps are useful for both planning for and then conducting landed missions.
“A recently released set of topography maps provides new evidence for an ancient northern ocean on Mars. The maps offer the strongest case yet that the planet once experienced sea-level rise consistent with an extended warm and wet climate, not the harsh, frozen landscape that exists today.” Press release, video, article (JGR Planets). [Universe Today]
A new map of Mars reveals the abundance of aqueous minerals—clays and salts that form in the presence of water—that were created during the planet’s distant watery past. “The big surprise is the prevalence of these minerals. Ten years ago, planetary scientists knew of around 1000 outcrops on Mars. This made them interesting as geological oddities. However, the new map has reversed the situation, revealing hundreds of thousands of such areas in the oldest parts of the planet.”
National Geographic looks at the rivalry between two early cartographers of Mars who based their maps on observations made during Mars’s “Great Opposition” in 1877: Nathaniel Green, whose Mars “was a delicately shaded world with landforms that gradually rose from vast plains and features that blended into one another” (pictured here) and Giovanni Schiaparelli, whose Mars had more detail—including those famous canals—but was less accurate.
I have a peculiar hobby of collecting Martian hypsometric tinting schemes: those sets of colors that cartographers use to depict elevations on the Red Planet. It’s a fascinating cartographic frontier. While the classic (and somewhat flawed) way of showing Earth’s elevations is to use 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, there’s no standard yet for Mars. Maybe centuries from now, one of the schemes below will become that standard.
The Digital Museum of Planetary Mapping is an online collection of maps of the planets and moons of our solar system. There are more than two thousand maps in the catalogue, some dating as far back as the 17th century, but the bulk of them, understandably, are much more recent; also understandably, Mars and the Moon are the subject of most of the maps (40 and 46 percent, respectively).
The site is more like a blog than a library catalogue: it’s powered by WordPress and the individual listings are blog posts, but that’s perfectly legitimate, albeit less elegant. (But then who am I to judge?)
The project was presented at the European Planetary Science Congress in Berlin last month: for news coverage, see Phys.org and Space.com; the press release is here. [WMS/WMS]
The Moon and Mars were relatively early additions to Google Earth; that application may have been migrated to the web, but the planets and moons keep coming. Yesterday Google announced the addition of a dozen other worlds in our solar system; the space layer of Google Maps now includes planets Mercury, Venus and Mars; dwarf planets Ceres and Pluto;1 Jupiter’s moons Io, Europa and Ganymede; and Saturn’s moons Dione, Enceladus, Iapetus, Mimas, Rhea and Titan. Large moons Callisto and Triton aren’t included, and Iapetus is projected onto a sphere rather than appearing as the bizarre space walnut it is.
A new gravity map of Mars that shows the thickness of the Martian crust based on gravity measurements from Martian orbiters, reveals a crust that is less dense and shows less variation than earlier maps. “The researchers mapped the density of the Martian crust, estimating the average density is 2,582 kilograms per meter cubed (about 161 pounds per cubic foot). That’s comparable to the average density of the lunar crust. Typically, Mars’ crust has been considered at least as dense as Earth’s oceanic crust, which is about 2,900 kilograms per meter cubed (about 181 pounds per cubic foot).”
Concomitant with the Survey’s map of Mars was a competition to design a map symbol to represent landing sites. The winner has been announced: the OS will use Paul Marsh’s symbol, which incorporates the Mars symbol with landing gear, on its Mars maps in the future.
The project is to select one candidate landing site and design an actual map that you envision will be useful in surface operations. We ask that you do not create simply a geologic map, but rather a product that can be used by the astronauts during their approximately one-year long mission within the Exploration Zone. This requires creativity, and it is also useful to have a good knowledge of surface features, surface hazards, science goals and the use of the proper cartographic tools.
The contest is open to students, young professional cartographers, and graphic artists in any country of the world.
Kenneth Field’s map of Mars (note updated link) now includes an option to add oceans, with checkboxes to fill the landscape to various elevations.
You can irrigate the planet below the areoid on this map using the water layers. You’ll notice the water layers aren’t blue. On Earth, water appears blue due to red, orange, yellow and green wavelengths of light being absorbed more strongly than blue and also the reflectence of the blue sky. Since Mars has relatively little atmosphere and it’s farther from the sun it’s likely water will appear differently. We’re imagining wavelengths will be absorbed differently, perhaps returning an alien green?
Daniel Macháček released his topographic map of Mars, based on the latest probe data, in November 2014. It uses the Mercator projection between 65° north and 65° south latitude and stereographic projections for the poles. It can be downloaded in insanely high resolution: 17,400×14,700 (78 MB JPEG, 106 MB PDF). His blog post (in Czech: use the translate button) has all the technical details. I particularly like the colour scheme he used for elevation data: the low-lying areas are coloured like deep oceans, which seems appropriate. [Maps on the Web]
A new gravity map of Mars, based on data from three orbiting spacecraft, has been released. “Slight differences in Mars’ gravity changed the trajectory of the NASA spacecraft orbiting the planet, which altered the signal being sent from the spacecraft to the Deep Space Network. These small fluctuations in the orbital data were used to build a map of the Martian gravity field.”
The data enables the crustal thickness of Mars to be determined to a resolution of approximately 120 kilometres. Here’s a short video explaining the significance: