AbstractThis article concerns the identification of the expertise that GI scientists have in common. Rather than attempt to be exhaustive, the approach is to identify a minimal set of expert topics shared across GI science. In this article, a set of five expert topics is proposed for this purpose: structure, uncertainty, dynamism, language and cognition, and design with geographic information. The article then examines the extent to which the literature lends support for these five topics, using two analyses: first, a qualitative analysis of the papers found in the 2006 Classics from IJGIS; and second a citation analysis investigating the occurrences of keywords related to the proposed expert topics. The results suggest that these five areas of expertise do indeed tend to distinguish research in GI science from that in other fields, and in particular where the expert topics occur in combination. The establishment of an acknowledged core of shared expertise should assist in interdisciplinary research and teaching collaboration, usually founded on a shared understanding of what expertise different partners can contribute.