Google Earth KML files seemlessly integrate with the desktop-based Google Earth software, allowing users to view locations of all platforms and learn about the observations made at each. Google Earth software is a free download. For more information visit the Google Earth website.

Geography Markup Language (GML) is the XML grammar defined by the Open Geospatial Consortium (OGC) to express geographical features. GML serves as a modeling language for geographic systems as well as an open interchange format for geographic transactions on the Internet. Note that the concept of feature in GML is a very general one and includes not only conventional "vector" or discrete objects, but also coverages and sensor data. The ability to integrate all forms of geographic information is key to the utility of GML *. For more information visit the OGC website.

(* GML definition above from Wikipedia website)