Infographics that incorporate maps are more popular than ever. Case in point: a few weeks ago, Nik Freeman put an interesting project online called "Nobody Lives Here." Simply summed up, it's a map (shown above) that puts together 2010 census data (which details how many people live in each vensus block) and shows all the places where nobody lives in the United States. It turns out that for a variety of reasons — more on that below — nobody inhabits 47 percent of the United States land area.

Freeman's map has gotten tons of attention, both online and from traditional media sources. As a map nerd (some call us "mapheads" à la the bestselling book), I was instantly fascinated and spent quite some time going over both the map that Freeman put together and his notes, which detail his technique and some interesting findings. (Be sure to check out the zoomable map if you want to delve into the specific empty spaces.)

Why look at where we aren't? As he wrote on the page, "Human geographers spend so much time thinking about where people are. I thought I might bring some new insight by showing where they are not, adding contrast and context to the typical displays of the country’s population geography." Wanting to know even more about the project and its findings, I sent Freeman all the questions that came to mind when I was poring over the map, and he was kind enough to take the time to answer. See our conversation below.

MNN: What's your background and interest in this topic?

Nik Freeman: I have a degree in communications and a degree in geography. Learning geography helped me understand the world, and my communications background helps me express that understanding. I enjoy making maps.

This particular map, and the concept of "unpopulation geography," was an accidental discovery. I was working on a different map involving U.S. population counts when I noticed the census blocks with zero population. Since it was a large data set, I thought I would save some space in my database by deleting them. But when I saw how many blocks I'd be removing, I decided to put them on a map and see what they looked like first.

I was blown away by the initial results. I knew the west was more sparsely populated than the east, but the extent was quite surprising. I didn't expect so much of it to be "empty." So I delved further into what the map was showing and decided that if I found it fascinating, others might as well.

There has been tons of public interest in this map project. Why do you think that is?

The reach of the map has certainly been much wider than I expected. I knew the map was cool and thought it might spark some discussions in a few geography and mapping circles. I did not expect it to blow up over the larger social web. It's been quite the learning experience in becoming "internet famous," if only briefly.

The novelty of the map — its flipping of expectations — probably has a lot to do with its popularity. It's an unexpected and unique view of the U.S. that I'm sure most of its viewers had never considered. It was something I never thought about until I stumbled upon it.

It's a very open-ended map too, subject to varying interpretations. People are free to read into it differing conclusions based on their own points of view. The most recurring theme in the comments I've seen so far have revolved around wanting to visit or move to the unpopulated places on the map. The desire to "get away" is apparently strong for a large swath of people, and I think the map resonated in that regard.

Other commentary has cited the map as an argument against the concept of over-population. Seeing all that "open space" convinced some people that there's still plenty of room to grow. That may be true by some measures, but most of the unpopulated places in the country are that way for a reason: much of it is harsh terrain where people would have a difficult and expensive time trying to live, even if they wanted to.

Also, the map was made without a political agenda, but that hasn't stopped some people from assigning their own views to it.

Finally, it seems the extent of the unpopulated places came as a shock to many. It certainly surprised me. Most Americans live in urbanized areas. When there are people and developed land seemingly everywhere (with more being developed and populated all the time), it can be hard to believe that nearly half the U.S. doesn't have anyone calling it home.

After a seemingly long decline, maps seem to be picking up as popular ways to think about data in the internet era. Any theories as to why they seem so relevant again?

The resurgence of maps in our culture, especially the kind that circulate on the internet, is, I think, largely the result of a broader focus on thematic data visualization. These maps are not the kind used to find where in the world Singapore or Karachi are located, or to figure out which route is the best one to the beach. Instead, they tell stories or describe a phenomenon or answer a question. In the past, these kinds of maps were locked up in textbooks and atlases. Many were out-of-date before they were even printed. But today, thanks to the internet, they are easily accessible on any webpage.

The storytelling aspect makes thematic maps incredibly appealing to the public. People want to understand the world, and that creates a demand for maps that explain what's going on or why things work the way they do.

At the same time, the past five to 10 years has seen a democratization of the geospatial tools and techniques of the trade. Free or cheap software that didn't exist a decade ago is now sophisticated enough to compete with programs that cost hundreds or thousands of dollars per year. Mapping and data enthusiasts no longer have to work for a large organization to get access to expensive tools. There's still a learning curve to creating great maps (they're not easy), but the tools to make them are easy to access. They're just a download away.

So, just as more people got into photography when they could pick up a cheap digital camera, the cost of learning has fallen to the point where anyone who has the interest can be making their own maps in a relatively short time. As a result, more maps are being made. And thanks to the internet, they're being shared easily.

In addition, the amount of data that is available to be mapped is tremendously vast. From free government data to data collected on smartphones, there are so many things to be mapped these days we can hardly keep up with them all.

All these trends have come together to create an environment where maps have taken a higher prominence in our culture.

As a lover of places where people are scarce, I was wondering if you had any additional data on places where, say under 10 (or 20) people live. Any idea how much more area, percentage-wise, this might make up, if 47 percent is totally uninhabited?

I must caution about reading the 47 percent figure too broadly. It includes places like airports, office parks, factories, shopping centers and so on. These aren't places that people call "home," but they likely have someone on-site 24 hours a day. If we filtered those areas, the 47 percent figure would shrink.

That said, your specific question is a little tricky to answer. Because census blocks vary in size and some can be quite small, it's possible (and likely) that many urban and suburban blocks contain fewer than 10 (or 20) people. Raw count by itself is not a very good indicator for sparseness.

If we look at density though, we can get closer to a meaningful answer. The area of the U.S populated by 10 people or fewer per square kilometer is 69 percent of its total area.

Are there future plans to include additional data on this map (super-low density areas maybe, like my question above) or something else?

No concrete plans. I may make some metro or state extracts to highlight the patterns that exist in developed environments. There's also potential for some change analysis to measure the change of sprawl based on blocks from the 1990 or 2000 census.

It's interesting that commercial districts and shopping malls are in the same category as national parks and near-uninhabitable areas. Did this surprise you when you did the research? I bet that hadn't occurred to many people.

This was the most fascinating part of the map to me. I expect harsh environments to have little-to-no population. But being able to trace the shape of a river or see the path of a highway just based on its lack of inhabitants was a revelation.

Likewise, being able to make out commercial districts, et al, raises some notions about land usage and settlement patterns in an urban landscape. It raises the questions of why a given tract of land is unpopulated. Maybe no one lives in those places for legitimate reasons (they're green space, noisy or polluted, for example). Or maybe it’s a sign of inefficient land management policies.

Do you think that uninhabited places are ignored by cartographers and social scientists in the obsession with all things urban?

The "social" in social science is people, so in that regard, it makes sense that scientists tend to focus on where people are. And in terms of abandoned places, there is active research on the topic in academia. So there is some attention being paid to uninhabited places.

I don't really know the state of research to comment with confidence, but there probably is room to investigate in a more quantitative fashion the forces that push people away from places (alongside the studies of which forces compel people to stay).

Can you provide some of the more interesting/weird/unique responses people have given to your question: "What trends and patterns do you see?"

I've yet to see any good academic dissections of the map. I'm sure those kinds of articles take time to write, so hopefully we'll be seeing them soon.

CBS Chicago posted a story highlighting some of the geography of that city, mentioning that O'Hare and many factory areas, as well as Fermilab, could be identified easily.

Some comments pointed out that a lot of the uninhabited western lands are owned and managed by the federal government. People are prohibited from inhabiting those lands permanently, even if they wanted to. The Homestead Acts were on the books for more than 110 years, so there's a reasonable argument that if those lands were worth living on, they likely would have been settled before the acts were repealed.

Other commenters found it interesting to be able to make out state borders amongst all the blocks in a lot of cases. Blocks are designed to not cross administrative boundaries, so all it takes is people living on one side of the border, with no one on the other, for state outlines to become visible.

As in my original discussion of the map, a lot of people brought up how Maine stands out. One commenter pointed out that it's the least inhabited portion of the Appalachian Trail and that hikers are advised to go in with at least 10 days worth of supplies. I've learned that much of the uninhabited land there is now owned by logging companies, but I'm still curious how that region went 400-plus years without being settled.

Are you working on any other projects now? More maps? Something else?

I've got plenty of maps in me. As I mentioned above, I have plans for some state and metro extracts to provide more detailed views of a few places. I've started basic work on a derived map highlighting which counties in the U.S. have the highest percentage of unpopulated areas. I'll eventually finish the map that I was originally working on when I discovered the unpopulated blocks.

I also have ideas for a few Texas-centric maps (where I currently live) as well as one based on a large dataset of UFO sightings. As long as I keep finding interesting data, I'll keep making maps.

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.

What is 'unpopulation geography'?
This map project looks at where human beings aren't — and brings some interesting data to light.