A few years ago I came up with the idea of FatFonts, a special kind of digits that encode quantity both in the shape of the digit (as in regular numbers) and in the amount of ink or black pixels (the area of the glyph is proportional to the number it represents). I then worked with Uta Hinrichs and Sheelagh Carpendale to develop the idea and publish a paper.
Although a quirky idea, FatFonts seem to have a bunch of usages… for example, they are convenient when you want to provide a table of numbers that is also a graphical representation. This allows the viewer (or the reader) to very quickly capture the overal distribution, but also to go in and read the specific number, which they can then use to compare to other numbers (in the FatFonts table or in their heads).
FatFonts are great in maps, and that is why Uta and I set out to create a poster that would give a picture of one of the most pressing issues of our time: world population. Thanks to SICSA (and our wonderful helpers Carson, Jed, and Michael), we got the time, money and support to develop the idea. The result is a poster that represents the population of the world using FatFonts.
The poster is made using an equal area projection of the world, and it represents data collected by CIESIN and others. Each grid in the main map, which represents an area equivalent to 200 by 200 km has a 2-level digit FatFont digit in it. That way we can know, with a precision of 100,000 people, how many humans live there. Naturally, the precision is as good as the data (and these are projections using 2005 data, the newest available), but it gives you a really good idea of where people really are. In fact, the map is so mesmerising that I have learnt a lot from it by just spending a lot of time looking at it. It is not only the distribution, but also the numbers. Obviously I am biased, but I strongly believe that seeing the numbers gives you a lot more than just representing density with colours, in part because colour scales are very arbitrary.
Since the number of dark pixels of a FatFont digit is proportional to the number that we are representing, we can calculate how many people each black pixel represents. For an A1 poster in the main area of the map at 600 pixels per inch, each pixel represents approximately 1880 people! FatFonts with the orange background are up by an order of magnitude, so there the ink of a pixel represents approx 18,000 people.

The South Eastern Mediterranean population is concentrated in the Nile delta (Egypt) and Palestine and Israel.
We partnered with Axis maps, who make wonderful typographic maps of cities, and we are selling them here. All the profits will be reinvested in research (e.g., helping pay research internships for students). We think that they are a wonderful present and that they are really fun to look at and discuss.
To give you a better feeling of the map, and because we like to try our new stuff, we have taken some Lytro images of the poster that you can explore in this gallery.