Are Wikipedia contributors running out of topics to write about? Recently, much has been made of the fact that the growth in the number of new Wikipedia articles has been gradually slowing and the number of volunteers apparently falling. But Wikipedia still has much to do: the map above suggests there are still whole continents that remain a virtual "terra incognita" and the next explosive growth in the online encyclopedia will come from places that have not previously been represented.

The map represents the roughly half million geotagged Wikipedia articles that fall within the boundaries of any one country. These geotagged articles are either about distinct places (such as cities, buildings, forests) or about events that occurred in distinct places.

There is clearly a highly uneven geography of information in Wikipedia. The United States has the most articles about places or events (almost 100,000), while some smaller countries such as Tonga have fewer than 10.

Stranger than fiction

But it's not just size that is correlated with extremely low levels of wiki representation. Almost the entire continent of Africa is geographically poorly represented in Wikipedia. Remarkably, there are more Wikipedia articles written about Antarctica than all but one of the 53 countries in Africa (or perhaps more amazingly, there are more Wikipedia articles written about the fictional places of Middle Earth and Discworld than about many countries in Africa, Asia, and the Americas).

There are some countries that are crammed with a dense amount of floating virtual information, such as Germany (with an average of one article tagged for every 65 square km), while others remain as virtual deserts, such as Chad (with an average of one tagged article every 17,000 square km).

Sharp divides between the Global North and the Global South can likewise be seen when looking at the number of geotagged articles per person. Austria, Iceland and Switzerland all have around one geotagged article for every 1,000 people, while in China or Guinea there is just over one article for every 500,000 people.

It needs to be pointed out that only a relatively small number of Wikipedia articles are geotagged. The main reason for this is that a lot of information simply isn't geotaggable: It wouldn't make sense to assign co-ordinates to the vast majority of articles on topics such as apples or Teenage Ninja Mutant Turtles.

Some explicitly spatial articles do remain untagged. The reason that Burkina Faso has more geotagged articles (1071) than South Africa (945), Kenya (217) and the rest of Africa is probably down to diligent editing rather than more actual content in Burkina Faso.

However, in all cases, these numbers pale in comparison to the huge number of articles in places such as the US (89,549) and Germany (54,634). So, I'd argue that: (1) the geographic biases in tagged v untagged articles are relatively small; and (2) because those biases exist we should pay more attention to the general patterns of geographic inequalities in content (ie the fact that there is much more content in the Global North than the Global South) than to the relatively minor differences between places.

Every day, countless decisions are made and countless opinions formed based on information available in Wikipedia. If this weren't the case, the articles on Israel, Kashmir and Taiwan would not host such hotly contested edit wars. Representations within the online encyclopaedia therefore undoubtedly have cultural, economic and political effects.

Unexplored territory

But what of the places that aren't even represented? We often hear claims that peer-produced information is broader in scope and more accurate than traditional methods of content creation. This is certainly true, particularly for topics that generate a lot of interest such as "Paris" or "New York". However, as we increasingly rely on (and trust) web 2.0 sources such as Wikipedia, what will be the effects of this new "terra incognita" in our shared map of knowledge?

It may be that when broadband reaches more parts of Africa – helped by the landfall of superfast cables in August – that more people there will start discovering Wikipedia, and that the site will see a second explosion of new editors and articles about places that have so far been ignored. Or it may be that by then Wikipedia will be passed by in favour of something new.

The answers are unclear, but we should nonetheless acknowledge the significant geographic gaps in an encyclopaedia that is described as having reached its limits. It is conceivable that it will only be a matter of time until a new generation of wannabe Wikipedia editors in Zambia, in Indonesia, and in much of the rest of the world begin to fill in the blank spots and construct dense layers of virtual representation.

But it is equally conceivable that as peer-produced projects such as Wikipedia become our primary sources of knowledge, we could begin to see permanent information inequalities between different parts of the world. In any case, it is clear that we are far from running out of topics to write about.

Mark Graham is a Research Fellow at the Oxford Internet Institute and blogs at zerogeography.blogspot.com