GTM is a graphical notation used to define ontologies (level 1) and represent Topic Maps instance data (level 0). Formally, GTM is specified in ISO 13250-7, that is, part 7 of the Topic Maps standard. The acronym GTM stands for Graphical Topic Maps notation.
GTM is currently in the earliest stages of development. There is no working draft yet. We do have some presentations, however:
The current editors are Lars Marius Garshol and professor Jaeho Lee. Feedback can be sent to them or to the topicmapmail mailing list.