map projections – The Map Room

Projection Connections: A Genealogy of Map Projections

Published on 22 December 2022 by Jonathan Crowe

Projection Connections: a diagram showing the relationships between various map projections by Daniel Huffman — Daniel Huffman

Fresh off of producing a (now sold-out) line of map projection trading cards, Daniel Huffman has produced a 16×24-inch poster showing the surprisingly close and entangled relationships between the various map projections.

I first learned about a couple of these connections several years ago. I don’t quite remember how or where, but I found out that the Mercator projection was equivalent to a Lambert Conformal Conic with the standard parallels set opposite each other across the Equator. And that if you moved both those parallels up to a pole, you got a Stereographic. My mind was suitably blown, and I saved it as a fun fact to share with people. This year, while working on The Projection Collection, I spent a lot of time on daan Strebe’s site looking up details, and I often saw his notes (usually derived from Snyder/Voxland) about how projections were related to each other. I started to realize there were a lot of these connections out there, and I thought it might be fun to diagram them in some way.

The diagram is digital-only (PDF) and donationware.

Map Projection Trading Cards

Published on 30 June 2022 by Jonathan Crowe

The Projection Collection (Daniel Huffman) — Daniel Huffman

Daniel Huffman’s map projection trading cards are now a thing you can order. Daniel, earlier this month:

A couple months back, I floated an idea for making some fun trading cards based on map projections. I’m very happy to report that several dozen of you responded and contributed designs to help make the set happen. I’ve been spending several weeks on managing everyone and working through logistics, and I’m pleased to now be able to offer a pre-order of The Projection Collection.

The cards can be pre-ordered here, with delivery later this year (or pickup at NACIS). Each pack has 16 cards, with complete sets not available by design—these are meant to be trading cards in the classic sense. Pre-orders will close on July 6, so you have until then.

Mercator: Extreme

Published on 3 May 2022 by Jonathan Crowe

To follow-up on xkcd’s Madagascator cartoon (previously), I missed the fact that clicking on the cartoon at the xkcd website actually did something, but Keir caught it: it links to Drew Roos’s Mercator: Extreme, an online tool that allows you to have some fun with the Mercator projection’s excessive polar distortion by making any point on the planet the North Pole and which clearly served as Randall’s inspiration.

xkcd’s Madagascator Projection

Published on 1 May 20223 May 2022 by Jonathan Crowe

xkcd: Bad Map Projection: Madagascator (29 Apr 2022) — Randall Munroe, “Bad Map Projection: Madagascator,“ xkcd, 29 Apr 2022.

Uncharacteristically for xkcd’s Bad Map Projection series, the Madagascator is actually totally legitimate as a projection. Not that it’s any less mischievous, mind.

Update, 3 May: Turns out there was more to this xkcd cartoon. See Mercator: Extreme.

xkcd: The Goode Homolosine to the Rescue!

Published on 6 February 2022 by Jonathan Crowe

Randall Munroe, “Sea Chase,” xkcd, 4 Feb 2022.

Randall Munroe’s map projection humour is increasingly on point, as last Friday’s xkcd demonstrates. (The mouseover text is even better: “There are two rules on this ship: Never gaze back into the projection abyss, and never touch the red button labeled DYMAXION.”)

Previously: xkcd: The Greenland Special; xkcd: All South Americas; Blame the Mercator Projection; xkcd’s Time Zone Map; xkcd’s Liquid Resize Map Projection.

Map Projection Explorer

Published on 6 January 2022 by Jonathan Crowe

Stefan Reifenberg’s Map Projection Explorer is another interactive tool that morphs a world map into the projection of your choice. The availability of data from the d3.js library seems to be enabling a lot of them. [r/Maps]

Previously: Map Projection Playground; Comparing Map Projections.

The Spilhaus Projection for Designers

Published on 22 December 2021 by Jonathan Crowe

The Spilhaus projection has been available to ArcGIS Pro users for nearly two years. Now, to expand the Spilhaus’s availability beyond ArcGIS users, John Nelson provides vector assets suitable for designers working in, say, Illustrator.

Previously: The Spilhaus Projection Comes to ArcGIS Pro; Everything’s Coming Up Spilhaus; About the Spilhaus Projection.

This Map-Print Basketball Hurts My Brain

Published on 15 December 202115 December 2021 by Jonathan Crowe

There is something decidedly off about a map-print basketball that stretches a Mercator projection across the basketball’s surface instead of, you know, doing it like a globe. Why? Why would they do such a thing?

It’s a Spalding ball exclusive to Urban Outfitters, it costs $29, and it hurts my brain. [r/Maps]

Map Projection Playground

Published on 12 October 2021 by Jonathan Crowe

A lot of fun can be had at Florian Ledermann’s Map Projection Playground, which loads up nearly a hundred map projections for you to manipulate: controls enable you to change the centre meridian and several other parameters. You can even overlay a simplified Tissot’s indicatrix! [Maps Mania]

xkcd: The Greenland Special

Published on 16 July 2021 by Jonathan Crowe

xkcd: Bad Map Projections: The Greenland Special — Randall Munroe, “Bad Map Projection: The Greenland Special,” xkcd, 14 July 2021

At some point, xkcd cartoonist Randall Munroe is going to put out a book focusing on his map-related cartoons, isn’t he. The latest in his “Bad Map Projection” series (previously: All South Americas, Time Zones, Liquid Resize) is The Greenland Special, an equal-area projection except for Greenland, which uses Mercator. And I thought he was messing with us before.

The Unicorn of Map Projections

Published on 4 May 2021 by Jonathan Crowe

It’s a shame that Sarah Battersby’s essay in The International Journal of Cartography, “The Unicorn of Map Projections,” is behind a paywall: it looks at the recent rash of map projections that purport to solve “all our mapping problems.” There have been more than a few that have claimed the title of “most accurate map”; Battersby refers to these projections as a class as unicorns. The most recent example of this I dismissed as the cartographic equivalent of a spherical cow; five years ago there was also Narukawa’s AuthaGraph map; and of course there was the Peters map.

The Spherical Cow Projection

Published on 31 March 2021 by Jonathan Crowe

Today is The Map Room’s 18th anniversary. When I started this blog back in March 2003, it was as an exercise in self-education: I liked maps a lot, but knew very little about them, and thought that the blogging process would enable me to learn things and share what I learned with my readers. The idea that I’m some kind of map expert is just silly: I have no professional credentials whatsoever, not in cartography, not in geospatial, not even in illustration. (I haven’t even taken geography since high school.)

But that’s not to say that I haven’t picked up some knowledge: I’ve turned my longstanding interest in fantasy maps into a few published articles (with more still in the works or in press), so I will concede the point on that front. But in general what I do have is exposure. Over the past 18 years I have seen just about everything to do with maps, and so I know a little bit about just about everything. Not enough to be employed at any map-related job, but 18 years of paying attention, of synthesizing everything I’ve seen and read, has afforded me some perspective.

Enough to call out obvious horseshit when I see it.

Continue reading “The Spherical Cow Projection” →

Map Projections for Babies

Published on 4 February 2021 by Jonathan Crowe

Late last year Dan Ford launched a Kickstarter to create a board book (i.e., a children’s book printed on paperboard) about map projections called Map Projections for Babies. Presumably intended to be in the same vein as other board books on surprisingly advanced science topics (Chris Ferrie has a whole series of them; Quantum Computing for Babies is a typical title), Map Projections for Babies “explains how we unwrap the round Earth to make flat maps. This guide for babies (and their loved ones) describes a complex concept in kid-friendly terms. […] This project began last year, when I was inspired threefold by my daughter’s curiosity, my love for maps, and a growing number of board books that condense complex concepts for babies.” The Kickstarter was successful, the book is now at the printing stage and is on track for delivery in April; additional orders will be accepted at some point. [Geography Realm]

Comparing Map Projections

Published on 17 August 2020 by Jonathan Crowe

Kai’s Comparing Map Projections mashes up two code blocks by Mike Bostock: Map Projections Distortions is a visualization of the types of distortion inherent to each projection; Projection Transitions morphs between projections. Combining the two is a neat trick. Refreshing to see the usual two combatants excluded. [Maps Mania]

SMBC Takes the Mercator Projection into Its Own Hands

Published on 27 February 2020 by Jonathan Crowe

SMBC: Mercator — From “Mercator”, *SMBC*, 24 Feb 2020.

Saturday Morning Breakfast Cereal’s take on the Mercator projection is … not what you’d expect. The punch line is similar to Christopher Rowe’s short story, “Another Word for Map Is Faith”: if you can’t make the map conform to the territory, make the territory conform to the map. Since we’re dealing with the Mercator projection, this requires some … escalation.