I’ve been playing with NASA’s WorldWind for a while. It uses the LandSat images and Radar Topography to give you 3D images of the big features. The information is good, you can switch views with ease, but performance has always been a problem for me. I fail to finish most sessions as server connection usually drops. Now Google has bought out a similar service, using the Keyhole Satellite images. From first appearances, it appears to have less data than the NASA service, but functionality is very similar. Where it wins is with performance and ease of use. The interface for Google Earth is far more friendly, designed for a more massive audience than WorldWind, which definitely has a scientific focus. All I need now is more time to play…whilst waiting for Microsoft’s entry into this space.