Here’s a gallery of all 68 map projections supported in ArcGIS 10.7.1 and ArcGIS Pro 2.4, from Bojan Šavrič and Melita Kennedy. Some interesting projections included here, some of which are only suitable for a specific region (such as the complex New Zealand map grid). No Gall-Peters, interestingly.
Chris Whong uses a clementine as a substitute for Tissot’s indicatrix: “I found myself eating a clementine this morning, and thought it would be interesting to slice up the orange peel on an 8×8 grid to visualize how much of the earth’s surface is represented in WebMercator tiles at zoom level 3. This is kind of an inverse of the Tissot’s Indicatrix above, showing chunks of the spheroid’s surface over the projected tiles that represent them in web maps.”
Alberto Cairo’s short piece arguing that the Mercator projection isn’t a monstrosity doesn’t cover particularly new ground: the Mercator was created for a specific purpose (bearing-based navigation) and is a good choice for small-scale maps, but it has no business on a world map. But it’s probably worth reiterating, since I still see over-the-top condemnations of the projection on colonialist grounds, channeling Arno Peters (which, you know: not new).
On Sunday Tom Patterson announced that the Equal Earth Physical Map is now available for download in JPEG, Illustrator and GeoTIF formats. Unlike its political counterpart, no territorial boundaries appear on this map (though cities do). Not having borders doesn’t mean that Tom and his collaborators won’t get into trouble with the names of natural features, though: I note they use Sea of Japan rather than East Sea, for example (see above). But, importantly, they’ve released the map into the public domain: if you don’t like their labels, or their choice of cities or colours or textures, you can make changes to the map and put out your own version.
It was announced today at NACIS that the Equal Earth projection is now available as a wall map—which is a necessary thing if it’s going to go toe-to-toe with the Peters map. The political wall map is only available as a download (three versions, centred on Africa and Europe, the Americas, or the Pacific): the 19,250 × 10,150-pixel, 350 dpi file results in a 1.4 × 0.74 m (55″ × 29″) print—assuming you have access to a large-format plotter. Not everyone does, so it’s only a matter of time, I suspect, before they have prints available for sale.
The map shows countries and territories in surprising detail (it includes Clipperton, for example); and while it does show disputed regions as such, its choices of boundaries and nomenclature won’t make it many fans in South Korea or India.
This image went a bit viral earlier this week. Some context. It’s from an August 2015 blog post at Le Cartographe, in which Alexandre Nicolas discussed (and rendered, above) a projection produced in 1942 by South African oceanographer Athelstan Spilhaus. In Spilhaus’s oceanic projection, centred on Antarctica, the world’s oceans form a single, uninterrupted body of water. Which, you know, it is. The continents form the edges of the map; there is … some … spatial distortion. As Alexandre wrote in 2015, “This projection is rarely used and it’s a real shame!”
The Gall-Peters projection is a second-rate projection with first-rate public relations; cartographers’ responses to the projection that focused on its cartographic shortcomings ended up missing the point. Something different is happening with the Equal Earth projection, which was announced last month as a response to Gall-Peters: an equal-area projection with “eye appeal.” It’s getting media traction: the latest news outlet to take notice is Newsweek. So, finally, there’s an alternative that can be competitive on the PR front, without having to mumble something about all projections being compromises until the eyes glaze over.
The end result is a Robinson-like pseudocylindrical projection that nevertheless preserves area—and, like the Robinson, is nicer to look at than a cylindrical equal-area projection like the Gall-Peters. It’s actually kind of impressive that they were able to square that particular circle. The article details their decision-making process and the math behind the projection and is worth a read. It’ll be interesting to see whether this map gains any traction. I wish it well.
Geo Lounge’s Elizabeth Borneman has a piece on Tissot’s indicatrix, which tends to turn up in discussions of map projections. (See, for example, this piece from Vox’s Johnny Harris, and the accompanying video.) And for good reason: it’s a useful visualization tool. All maps distort—representing a curved surface on a flat plane, et cetera, et cetera—but a grid of Tissot’s indicatrices superimposed on a world map will measure the distortion—linear, angular, by area—produced by that map’s projection. On the Mercator projection, the indicatrices remain perfect circles, but grow larger toward the poles; on equal-area equatorial projections, they maintain their size but squish into ellipses; on other projections they also angle left or right depending on how close they are to the edge. On compromise projections like the Robinson (see above), they do all three.
“A world map tells a lot about the person who has made it, or about the market it is made for,” says Frans Blok. The edges of equatorial projections are determined so as to put the map’s audience at the centre of the map: European maps put the Bering Strait at the edges, Australian and Asian maps the Atlantic, American maps break Asia in two. If, however, only the polar regions were habitable—or if you were making a map for penguins—you might use a polar projection centred on Antarctica.
“And no, for European use this map is less suitable. But there aren’t that many penguins living here,” says Blok. [ICA]
With all this recent talk about map projections, it might be worth pointing out the existence of Flex Projector, a cross-platform Java application for creating map projections, now at version 1.0.6. Yes, creating: if you want to invent your own map projection and slap your own name on it, you can do that with this app; others certainly have. (You will need to have Java installed on your computer.) Heck, Tom Patterson’s Natural Earth projection was built with it. [GIS Lounge]
Atlas Obscura’s Cara Giaimo has an in-depth look at the reaction to the decision by Boston public schools to adopt the Peters projection in teaching materials. It’s well worth taking the time to read; the general gist from several cartographers and commentators is that swapping the Mercator for the Peters isn’t that much of an improvement. Though it includes comments from yours truly (I was in touch for this article), Giaimo talks to people who actually do know what they’re talking about, including Mark Monmonier (who, again, literally wrote the book on the Mercator projection) and Matthew Edney (who spoke to WZON 3 about this topic earlier).
Joshua Stevens, NASA’s data visualization and cartography lead:
(2/2) Are kids being taught that? If so, adopting any *1* projection is counter to learning why *many map projections exist & have purpose*