Hello,
I found out that data from satellite navigation technologies on boats can also be used to create charts of the seabed: http://www.youtube.com/watch?v=BjFh-cWR20A.
It looks like it is possible to obtain accurate maps by aggregating a lot of data packages provided by a multitude of small boats.
Did any of you participate in similar activities? What do you think about it?
Matteo
