Wikis, such as Wikipedia, have become increasingly popular in recent years. They allow anyone to easily contribute to collaboratively written content. To better organize content, users in Wikipedia assign categories to articles, or create new categories if needed. The resulting semantic coverage of a wiki's articles over its categories is worth studying but not easy to obtain. To provide a better understanding, we created an approach to visualize an entire wiki by creating a graphical representation that is similar to a geographical map. This enables even untrained users, as well as people outside the field of computer science, to obtain an easily understandable overview of a wiki. © 2011 IEEE.