Subway map model explains metadata

A team of students and faculty from the University of Montreal developed this handy visual representation of metadata called the MetaMap. According to the site, the MetaMap is
\”a pedagogical graphic which takes the form of a subway map. Its aim is to help the information science community to understand metadata….\” You\’ll need to download something called an SVG Viewer plugin to view the map.

Could someone kindly tell me which Topic I should have put this under, besides news? Is metadata a subset of information architecture? Or is it its own thing?