Hello Raphael, I would be curious to collaborate to your greeeat project. I'm graphic designer, and I like to code, so I would be interested into working on the user-interaction part. Can I give a try ? I already worked on map projects (http://atlas-sensible.net/, http://archipels.org/, http://zoneadanser.org/), so I have some parts that can be recycled and some tips. I already clone the project, but I think I need a database to make it work, isn't it ?