Data visualisation typically focuses on the data itself, but in some cases the metadata is interesting in its own right. Lately I’ve been thinking a bit about how to visualise the structure of metadata. Ultimately this could be combined with a data visualisation to make something that coherently shows both the data and its structure.
Harmonised trade is particularly fascinating. It classifies products into a bewildering array of categories. I can’t imagine the effort required to create and maintain this system. As an experiment I made a visualisation of the New Zealand flavour of harmonised trade. Above is a static picture — each circle represents a category and shows its sub-categories. An interactive version is here, where you can click a category and see what it is.