Drawing (visualizing) a graph (or maybe Net Work) dataset. See Graph Theory.
http://www.compendiumdev.co.uk/alttools/modeltools.htm
Open Office-Draw
- has connectors that work (follow moved node)
export as SVG! (but not a native format, and can't import it!)
doesn't appear to auto-word-wrap text within nodes, and SVG rendering is pretty bad
Many (but not all) use GML as a data format.
good to have SVG view?
Mind Mapping is a subset.
Piddle is is a Py Thon module for creating two-dimensional graphics in a manner that is both cross-platform and cross-media; that is, it can support screen graphics (e.g. Quick Draw, Windows, Tk) as well as file output (Post Script, PDF, GIF, etc.).
Mathemat Ica and its clones
Network X Py Thon library https://networkx.lanl.gov/wiki
Cor Da free version http://www.corda.com/products/freeware/
Pre Fuse Ja Va - http://prefuse.sourceforge.net/
example of force-directed graph of pages on a Wiki Space.
Gliff Y Web App (!?) http://www.gliffy.com
looks like a Flash app, but does have export of JPEG/PNG/SVG
- hey, it actually does connecting vectors that move with either end! (Unfortunately they're right-angled, not pretty curves.)
Touch Graph: for rendering, not editing
LGL/Large Graph Layout http://lgl.sourceforge.net/
Ubi Graph http://www.ubietylab.net/ubigraph/index.html
AJAX/Java Script libraries?
http://www.smashingmagazine.com/2007/10/18/charts-and-graphs-modern-solutions/