Google Earth is a flexible mapping and display tool that is installed on a local computer, and accesses on-line data sources provided by Google. These data sources include aerial imagery at a variety of scales and additional data hosted by Google. The user needs to have internet access to view the data provided by Google. Once Google Earth is installed it allows the user to "zoom in" and view satellite and photographic images on any place in the world. The user can also change the perspective of their view to panoramic, and they can "fly" from one area of the globe to others as if in an airplane. It includes 3-D representations of topography and, of buildings (for selected areas), and provides street view photography for some locations. It includes links to a large number of external services that provide additional information, such as photos of points of interest. Time-controls allow you to select imagery from a number of different years for analyses of landscape change.
If you download or are given a file in KML or KMZ format, you can set your local computer preferences to automatically start Google Earth when the file is "clicked".
In addition to its display capabilities, Google Earth can also be used to create data through on-screen digitizing. It produces KML/KMZ files that can then be used with other GIS products such as Google Maps, ArcGlobe and ArcMap.
A limited version of Google Earth is available for mobile devices such as cell phones.
Google Earth is free, but professional versions that include additional capabilities are available for purchase.
Users can convert GIS to KML/KMZ through tools available within standard GIS software projects.