A study presented earlier this month at the Europlanet Science Congress maps the variations in Mars’s gravitational field.

Dr Root and colleagues from TU Delft and Utrecht University used tiny deviations in the orbits of satellites to investigate the gravity field of Mars and find clues about the planet’s internal mass distribution. This data was fed into models that use new observations from NASA’s Insight mission on the thickness and flexibility of the martian crust, as well as the dynamics of the planet’s mantle and deep interior, to create a global density map of Mars.

The density map shows that the northern polar features are approximately 300-400 kg/m³ denser than their surroundings. However, the study also revealed new insights into the structures underlying the huge volcanic region of Tharsis Rise, which includes the colossal volcano, Olympus Mons.

Abstract, press release, Universe Today.

Previously: New Gravity Map of Mars.

The Global CTX Mosaic of Mars, produced by CalTech’s Bruce Murray Laboratory for Planetary Visualization, is a 5.7-terapixel mosaic of the Martian surface at a resolution of five metres per pixel. The mosaic is available in a number of different formats (via ArcGIS Online, KML, shapefiles), as well as via this online viewer; and the Lab is quite transparent about how they constructed it from Mars Reconnaissance Orbiter Context Camera (CTX) data. [Maps Mania/La Cartoteca]

How often do Star Trek tie-in novels come with maps? John Jackson Miller’s Strange New Worlds novel, The High Country, which comes out today, includes maps of the low-technology world on which it is set; in Miller’s Twitter thread last month, he wondered whether his book was the first, but it turns out that a 2000 Deep Space Nine novel also had maps. Amazon (Canada/UK) | Bookshop

In my article about maps in science fiction I made reference to the maps in Kim Stanley Robinson’s 1993-1996 Mars trilogy. Mastodon user 65dBnoise decided those maps were “very few” and “very coarse” (he’s not wrong¹) and made some higher resolution maps based on USGS topographical maps of Mars.

The USGS’s Astrogeology Science Center highlights three geologic maps of Mars released in late 2021. The maps are large-scale, focusing on specific Martian features (e.g. Olympus Mons, above).

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.

The maps are of Olympus Mons Caldera, Athabasca Valles and Aeolis Dorsa. Interactive versions, with toggleable layers over spacecraft imagery, are also available: Olympus Mons Caldera, Athabasca Valles, Aeolis Dorsa.

“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.”

A new study maps the possible locations of subsurface water-ice reservoirs, vital for any crewed missions. [Sky & Telescope]

Kenneth Field’s virtual globe of Mars follows in the footsteps of his 2016 map.

Interactive maps showing the locations and paths of the Curiosity and Perseverance rovers. [Maps Mania]

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.

Huffman looks at fifteen schemes in total in the post, and in this video on YouTube:

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.

The Planetary Society’s Emily Lakdawalla noticed a thing, though:

Anybody know who I should talk to at @Google to let them know that several of the icy moon maps have names & image offset by 180 degrees?

— Lady Lakdawalla of Baltis Vallis (@elakdawalla) October 16, 2017

Emily reports that this bug affects several moons of Jupiter and Saturn; Google is apparently already on it and may have fixed it by the time you read this.

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).”

Hand-made globes are increasingly a thing, apparently. As Atlas Obscura reports this week, Michael Plichta’s company, Planetenkugel-Manufaktur, is producing a hand-crafted globe of Mars with a twist: it’s based on Percival Lowell’s maps, which (erroneously) showed the Martian surface covered in canals. It’s delightfully retro and I love it. Here’s a video:

Nowhere on the website is a price mentioned, which tells me that I won’t be able to afford one, damn it.

• 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 ICA’s Commission on Planetary Cartography has put out a call for maps of the 47 proposed exploration zones on Mars.

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.

More at the ICA and All Over the Map. [Leventhal/WMS]

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?

[Maps Mania] A print version is also available: it’s a one-gigabyte PDF that measures 38″×72″ [Kenneth Field].

Previously: Kenneth Field’s Map of Mars.

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:

Another online map of Mars, this one titled (Is There) Life on Mars? and produced by Kenneth Field using ArcGIS. On the information pane he says, cryptically, “There’s a hidden element on the map that explains why I really made it. Happy hunting.” [via]

Eleanor Lutz’s map of Mars isn’t exactly medieval in style (that’s not the right word for it), but it applies an ostensibly old aesthetic to a very modern map subject. “I thought it would be fun to use their historical design style to illustrate our current adventures into unexplored territory. […] Since the base map is hand-drawn I also added an overlay of actual NASA topographic imagery. This way even if some of my lines are a little off, you can still see what the actual ground looks like underneath.” Whatever you call it, it looks amazing. [via]

The Ordnance Survey has created a map of Mars. “The one-off Ordnance Survey Mars map, created using NASA open data and made to a 1:4,000,000 scale, is made to see if our style of mapping has potential for future Mars missions.” It looks very much like a topographic map of Mars might; the reduced version is a bit more screen-friendly.

• Dawn’s first colour map of Ceres: map-projected false-colour images of the dwarf planet taken as the spacecraft approached, assembled from images taken through blue, green and infrared filters. (Previously: At Ceres.)
• An elevation map of the Ares Vallis region of Mars (above) from the DLR, the German space agency (via io9).
• A map of known exoplanets in the Milky Way; most of them were found during the Kepler mission, which pointed at a a particular region of space.

As I said during the Q&A part of my fantasy maps presentation at Readercon (see previous entry), maps of other worlds in the solar system are usually images from space probes that have been set to a map projection. The key word is usually. On Monday the U.S. Geological Survey released a geologic map of Mars that “brings together observations and scientific findings from four orbiting spacecraft that have been acquiring data for more than 16 years.” Via io9 and Wired.

Here are some map books that I recently found out about:

• Mr. Selden’s Map of China: Decoding the Secrets of a Vanished Cartographer by Timothy Brook (Bloomsbury Press/House of Anansi Press/Profile Books, 9/13). A book-length study of the enigmatic Selden Map of China, donated to the Bodleian Library in 1659 and only rediscovered in 2009. (Amazon)
• The Golden Age of Maritime Maps: When Europe Discovered the World by Catherine Hoffman, Hélène Richard and Emmanuelle Vagnon (Firefly Books, 9/13). One of those big, illustrated books of old maps; this one looks at portolan charts. It’s an English translation of L’Âge d’or des cartes marines. (Amazon)
• Maps of Paradise by Alessandro Scafi (University of Chicago Press, 11/13). Explores “the diverse ways in which scholars and mapmakers from the eighth to the twenty-first century rose to the challenge of identifying the location of paradise on a map, despite the certain knowledge that it was beyond human reach.” (Amazon)
• The International Atlas of Mars Exploration: The First Five Decades, 1953 to 2003 by Philip J. Stooke (Cambridge University Press, 9/12). The first of two volumes (the second will be subtitled Spirit to Curiosity) that maps the extent of exploration by orbiters and landers. (Amazon, author’s page)