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.
A new study maps the possible locations of subsurface water-ice reservoirs, vital for any crewed missions. [Sky & Telescope]
The European Space Agency’s new Climate from Space website presents satellite data on a host of different climate indicators, from aerosols to CO2, from land cover to sea ice, via 3D virtual globes. From the announcement:
The new, easy-to-use site provides access to the same satellite observations used by scientists to understand climate change and support international organisations such as the United Nations Framework Convention on Climate Change (UNFCCC) and Intergovernmental Panel on Climate Change (IPCC) to drive action.
There is a suite of 21 climate data records to explore, which are generated by ESA’s Climate Change Initiative. The suite includes sea level, sea surface temperature, soil moisture, snow depth and the greenhouse gases, carbon dioxide and methane, as well as new visualisations for the latest climate variables records such as permafrost and lakes.
The National Maritime Museum is closed right now, obviously, but in the meantime they’ve given us a virtual version of one of their treasures: a 1541 table globe by Gerardus Mercator.
The digital globes will be available to view on the British Library website—www.bl.uk/collection-items—from 26 March, via a viewing platform which includes an augmented reality function (available on phone or tablet via the Sketchfab app). This online access will allow unprecedented up-close interaction with the globes from anywhere in the world and means that for the first time, a variety of previously illegible surface features on the globes can be read.
A total of 30 globes are being scanned this way. [The Guardian]
Web mapping uses Web Mercator. As Kenneth Field points out, this is fine at large scales, but at small scales you end up replicating the problem of using the Mercator projection on a wall map of the world.1 Zoom out in Apple Maps: using the map layer you get a Mercator; using imagery you get a virtual globe (basically, an orthographic projection you can spin). Ditto in Google Earth. But Google Maps, after some tests and starts, now does this in its map layer—and not just in Chrome, either. This means, among other things, that Antarctica is usably visible, as are the Arctic regions—and, of course, Greenland is its proper size at small scales.
All of this, by the way, is in French. If reading French is not your thing, the Harvard Map Collection also has a pair of Mercator globes, which you can view via their (rather dated) website.
The David Rumsey Map Collection has a number of virtual globes, but its AR Globe app may be the most unusual way to view them. Released last December for the iPhone and iPad, it uses augmented reality to superimpose one of seven celestial or terrestrial globes from the 15th through 19th centuries. The globes can be manipulated—spun, zoomed in and out—or observed from the inside (which is a good thing with celestial globes).
To be honest I’m not sold on using augmented reality to view virtual globes. It’s one thing to use AR to superimpose IKEA furniture in your living room: that makes sense, because it helps you visualize where the furniture would go and what it would look like. But it’s hard to see the utility of plunking a virtual globe in your living room: what’s the point of adding your surroundings as a backdrop? Case in point:
It’s neat but not particularly useful, is what I’m saying.
Map to Globe is an online tool that makes a globe out of any two-dimensional image. (Caitlin went for the Tabula Rogeriana.) For best (read: least distorted) results, you want to upload a 2:1 ratio map in an equirectangular projection. Some examples here.
Meridian, an “experiment” from the DX Lab at the State Library of New South Wales, overlays old maps onto virtual, 3D interactive globes. Two globes have been created to date—one based on the 1706 Miranda world map (previously), the other on a set of Coronelli globe gores from 1693—with more in the works. Details here. [Cartophilia]
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;2 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.