Google Earth is a powerful but relatively simple geospatial "browser" used to access and visualize geospatial data overlaid onto real world, high resolution satellite imagery that you can navigate in 3D. This is a program you install directly on your computer to use unlike Google Maps which is Google's 2D mapping application that you access through your web browser. In most cases Google Earth and Google Maps will support the same imagery. Google Earth started life as Keyhole, a small 3D imaging and mapping company that Google acquired and then released Google Earth in the summer of 2005.

Additionally, Google Earth makes it very easy to create placemarks of locations and put these in folders that you can organize. You can also save out files, email files and easily annotate placemarks you create or others create in Google Earth. This is all possible through Keyhole Markup Language, commonly known as KML. KML is modeled on the widely used data structuring format known as XML (extensible markup-language). KML is a subset of XML specifically developed to describe the geospatial data that Google Earth displays. Google is gradually incorporating KML into its Google Maps application so this data can be shared between Google Earth and Google Maps.

The ease of sharing Google Earth files also makes Google Earth a power collaboration tool. In the past year and a half over 200 million unique downloads of Google Earth have occurred and now there are literally millions of placemarks and other creative uses of geospatial data accessible through Google Earth.

For more information visit the Google Earth website here.