By Aaron Schiff 04/11/2015


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.

A couple of interesting examples are the harmonised trade system, and ANZSIC. Both of these are hierarchical classification systems, for international trade and industries respectively.

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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.

The code is here. I also experimented with an HCL colour space interpolation in D3, for the outer circles.