Left: A Map of Vesuvius (1832) by John Auldjo. Right: Hurricane Katrina Flooding Estimated Depths and Extent (2005) University of Otago, NOAA

An interview with John Hessler, a cartography expert at the Library of Congress and one of the people behind the new book, Map: Exploring The World.

Few people in the world know their way around a map like John Hessler does. The Library of Congress’s “Specialist in Modern Cartography and Geographic Information Science” can look at a Renaissance, bit matrix, or Minecraft map and explain what each signifies and how they all relate.

Hessler and a team of contributors have put together a stunning cartographic encyclopedia titled, Map: Exploring The World ($59.95, Phaidon). In it, 300 maps tell the story of 5,000 years of human history, just not in chronological order. Map’s layout draws connections between eras, places, and themes with each turn of the page.


One minute, you’re comparing a hand-drawn map that charts lava flow from Mount Vesuvius between 1631 and 1831 with color-coded satellite imagery of flooding from Hurricane Katrina. Pages later, you’re comparing an 1875 “Porcineograph” of the United States with a 2013 “Tacografia” of Mexico.

The connections made in Map feel especially useful as digital tools proliferate and it becomes easier to chart what we want to see: Wind as it blows, disease outbreaks as they spread, even geographic fantasies as they pop into our minds. The technologies change, but the needs aren’t that different. “Generally, you’re still abstracting from the complexity of the world to make some sort of point and you’re doing it visually,” says Hessler. “I think the visual aspect of it is still its power.”

CityLab recently caught up with Hessler at his office at the Library of Congress to talk about Map, his own work, and what about cartography excites him today:

How did this book come about?

When Phaidon approached me about a book on the evolution of cartography, we started talking about the definition of a map, what a map was, and what we could include, so there were a lot of these philosophical back-and-forth discussions on the nature of the word “map.”

My Lost Gloves from Mapping Manhattan, 2013, Becky Cooper. (Courtesy: Patricia Marx)

The question of how to present the material came up. It didn’t seem to me, nor did it seem to them, that a chronological presentation would make any sense because that type of structure had been used so many times before. What we tried to do was compare and contrast two maps over two pages. I think that’s the strength of the book: it shows you these thematic ways that [maps] have been done over time. There’s a map of lava flows on Mount Vesuvius on one page and on the other side there’s the flooding in the Upper Ninth Ward from Katrina. They’re separated by two and a half centuries but you’re seeing mapping of natural disasters using the best technologies that were available at the time.

How long did it take to put together?

Phaidon was extremely efficient. It really wasn’t even a year. It’s a beautiful book and hopefully it has more than your normal “great maps of history” kind of thing. I hope we pulled out stuff people have never seen before.

Human Mobility and the Spread of Ebola in West Africa, 2014, Flowminder Foundation. (Courtesy: Flowminder Foundation and WorldPop project)

What are you working on currently?

A lot of things. I’m the library’s modern cartography expert and that requires both acquisitions in the digital databases and keeping up on the current trends in technology. Also, doing my own research on subjects in the collection or out there somewhere that seem interesting and might be applicable to a library setting at some point.

Right now my main area of research is the topological foundation of GIS, very theoretical stuff in geographic information sciences. And I’m also running [a project], “The History of Computer Cartography Programs,” which involves collecting all of the papers and manuscripts and algorithms from some of the people who basically began computer cartography back in the 1960s and ‘70s, hence the IBM360 tapes sitting in the middle of the floor.

What have you been finding in these IBM tapes?

Computer cartography created a real revolution in map making. In the 15th and 16th centuries, people started printing maps on paper. Printing technology increased, it got better, surveying techniques got better, but for the most part during that entire period a map was printed on paper. There was some visual play and some rhetorical things that you could do but for the most part you were kind of limited by that framework.

But in the 1960s and ‘70s, with the advent of computers, it just exploded. So now you can add dynamics, the third dimension, we can do all sorts of things that make cartography come alive. We’re mapping things that no longer have any terrestrial or celestial foundations: Internet searches and people’s cellphone motions and social media connections, stuff like that.

During the time that a lot of this stuff [early computer mapping] was really being kind of hashed out, there was a lot of free thinking, there’s a lot of experimentation going on—especially in places like the Harvard Lab for Computer Graphics which really put GIS on the map. I’m really just looking at their thoughts, the philosophy behind it, some of their dead ends. There are lots of pure mathematical papers that have absolutely almost nothing to do with cartography but they thought maybe there would be an algorithm or something really deep inside this stuff. All that kind of experimentation when a field is about to go through a revolution is really interesting.

Are any of those maps in this book?

There’s not much early [computer] stuff in the book. The computer cartography that ends up appearing in there is the really good stuff that’s happening now. That’s mostly because of the visuals. If you look at some of the earliest computer-era maps, they’re not exactly the most visually appealing. They’re dot-matrix printed, among some of the first actual printed computer cartography.

There was a computer program called SYMAP that was developed at Harvard in the 1960s and they had this correspondence course where you learned how to [use it] and they sent you the piece of the program. The D.C. police department was among the first in the country to begin using it to chart crime statistics. It’s kind of interesting because they correlated it to things like income and housing prices. It’s kind of amazing. It was fairly sophisticated for 1968 or 1970.

How big of a role did the internet play in the sophistication of computer cartography?

It’s a big part of not only being extra visual but also the capacity for a lot of people to participate. Crisis mapping and things like the Ebola maps—crowdsourcing stuff really did have an effect on that.

But really it was just the computational power that has changed everything. The line is blurred now between what is cartography what is data visualization. There are all sorts of aesthetics coming into cartographic presentation that were never there before. It’s an exploding field. I’m teaching a course this semester at Johns Hopkins on brain mapping, so it’s even including what’s inside our heads.

Mapping the Brain, 2014, Human Connectome Project. Courtesy: Laboratory of Neuro Imaging and Martinos Center for Biomedical Imaging
Are there eras or cartographers you’re especially fascinated by?

Early in my career I wrote on Renaissance cartography but now I’m really interested in breaking down the design of cartography today and how it’s being appropriated by lots of different things, like Minecraft, for instance.

And then there’s the crowdsourced stuff, the crisis mapping and things like that, they’re just amazing. If you look at the Facebook map in the book, you’re seeing the geography of the world being produced by friend connections. When you start looking at it you say, ‘Oh, it looks like the world,’ but then you look closely and you see there’s no China and no Russia and you’re immediately seeing something about the world just by the social connections that people are randomly making.

We’ve mapped the globe with GPS and satellites as precisely as we’re going to map it, but the real growth is in how we can present the spatial data and understand what it’s telling us.

I’m also fascinated with artists’ use of cartography, like Ai Weiwei’s maps and what he’s trying to say with them. One of my favorite [maps in the book] is the untitled map [by Guillermo Kuitca], the one that’s drawn on mattresses.

Daylight Map, 2005, Olafur Eliasson. (Courtesy: The artist, neugerriemschneider, and Tanya Bonakdar Gallery)

Does the Library of Congress collect art maps?

We don’t deal necessarily with the pure artist map. We do have all sorts of literary and artistic maps, but for the most part they tend to fit into the more traditional mold.

Does the Library have a hard time keeping up with and categorizing new digital maps?

We do. We’re getting a much better handle on it now but as with anything in the collecting or library world, you’re always a step behind the people who are producing the materials.

It was easy when they were being produced on CD and your databases were coming in on CD but now stuff is coming directly through servers and embedded in websites. National mapping surveys, high-scale maps that Congress and the State Department would use—which used to be the bread and butter of what was collected here—are not being produced on paper anymore.

It’s a matter of keeping track of and collecting that kind of material, making sure it’s on servers and that you have the metadata associated with it so you’re sure you know what it is.

Flight Patterns, 2005, Aaron Koblin. (Courtesy: Aaron Koblin)

Are there mapping principles that have carried over from traditional, geography-rooted maps to today’s data maps?

Now, people can be a lot more creative, a lot more complicated. People used to have to worry about distances and metrics and scales but with the mapping of networks and things like that, you’re only worried about connection. You’re not worried about how far things are. Some of the principles in the newer maps are even more abstract than the ones that people were making just a few years ago. But the underlying principles still involve a visual 2-D projection of some complex thing going on in the world that you want to make a point with.

What kind of impact has Google Earth had on the kind of maps you’re coming across these days?

When the big Blue Marble photograph was first seen, there was this idea that it was going to change people’s view of ecology and everyone was going to become an environmentalist because of it. It was a big deal to see that image and now it’s just become so commonplace that no one even thinks about how incredible it is to look down on Earth from that perspective or just the technology it takes to create that image.

Tweetping, 2013, Franck Ernewein. (Courtesy: Tweetping.net)

In the space of 40 years, we’ve come from this very primitive satellite that was taking photographs and scanning the pictures one line at a time, which took hours, to being able to just go online. It’s changed people’s perspective on space. People don’t think about distance anymore. It’s almost as if the geographic distance has evaporated.

It puts space in front of us as thing that we operate in but no longer think about. I think that’s why people get so frustrated in their cars when they want to get someplace quickly, because they’re so used to thinking distance doesn’t exist.  We’ve become spatial animals, we’ve become people that really track ourselves everywhere we go. When you go for a run, you’ve got your little Nike thing hooked to your cell phone. When you’re on Twitter you can use its place location wherever you’re tweeting from.

What are the most unique maps you’re coming across right now?

Cartography has expanded to the point where it used to be just about one world and now it’s about infinite worlds. It’s not just wayfinding—it’s world-making.

It’s still about mapping what’s here and what’s there, but cartography is also becoming an experimental field. One can make experimental maps that say, ‘This is how people would behave in [this space], and here’s how the shadows would appear, and this is where transportation would go through.’ We’re building simulated worlds.

Those are the things for me that are the most exciting right now. The Wind Map, for example, is just a perfectly designed map. It’s mesmerizing. It’s so simple but so much data is being used to generate that.

This interview has been edited and condensed.

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