I make charts for our charting software directly from Google Earth. You see exactly what things look like, as well as exactly their positions, and you can overlay it on the marine charts with varying transparency so you can see depth info and laugh at how ludicrously inaccurate the most up-to-date marine charts are for most of the world.

It is probably only a matter of time before Google Earth becomes real-time and you can watch your boat navigate around on it - just like those old-fashioned chart plotters used to do.

Mark