Open source relationship mapping/visualization APIs?

A local group is mapping the relationships between board members and various organizations around my town. I am trying开发者_运维百科 to help them get some visualizations together.

The visualizations focus on relationships between people and organizations eg who is on which boards and will be drawn dynamically. I am assuming I will be generating XML via PHP or Perl in order to feed the map drawing engine.

I am hoping to find a mapping API/library like the one for

http://www.theyrule.net/ > Popular Maps > Amazon.com

Anyone seen anything like this?

---

http://polygeek.com/4613_actionscript3_mapping-api-adobe-flash-platform

---

This looks promising!

http://code.google.com/p/canviz/

demo of CanVis: http://www.ryandesign.com/canviz/

and CanViz or similar is under the HTML 5 hood of

http://wordvis.com/