The concept of mind maps is raised pretty often when talking about learning and acquiring understanding of a concept, but it always bothered me.

I feel like it's simply an esthetic take on a flat tree structure, with pictures. There is no loss of information when going from one form to another, just a different use of the space.

In particular, mind maps usually offer no way of connecting sibling branches together (diamond shape), so it's actually pretty limited compared to a graph of nodes.

https://cdn.fosstodon.org/media_attachments/files/111/193/431/255/027/638/original/4e381b84aa94e160.jpg 

 Vym can do both node links and multiple roots.  You need to add the modifiers mode toolbar to get the node links.  Vym generates decently consistent XML, so you can even translate to full-on semantic modeling -> RDF, etc. Along those lines, check out full-on dynamic graph tools like Magnus Jacobsson's d3-graphviz.  He has some demos that work at the speed of a mindmapping brainstorm session.  Whiteboards are great and all, and accessible, but why do double data entry? Keep your models. Reuse.

https://cdn.fosstodon.org/media_attachments/files/111/194/503/346/188/009/original/4cbb5f13d1fe1c18.png