File Extension KML
File extension KML is most commonly used to refer to a Keyhole Markup Language file. KML files are primarily used to store geographical information in a standard XML format which is used by Google Earth. The KML file extension is also used to store emulator keyboard configuration information for a number of HP calculators, though these are fairly uncommon.
Keyhole Markup Language was originally created by a software company called Keyhole Inc for use with Keyhole Earth Viewer, which later became Google Earth following Google's acquisition of Keyhole Inc in 2004. The KML file format was developed specifically to store geographical information and annotations which could be overlaid on maps. KML files contain a longitude and latitude as well as place markers, polygon shapes, images and text which can be used to illustrate or label a specific place or area on a map. Additional information, such as camera angle and altitude as well as linked textured 3D objects can also be stored for use with 3D earth browsing software. KML files allow developers to create customised layers of information which can be overlaid on existing maps for illustration or abstraction purposes.
The KML format has been accepted by the Open Geospatial Consortium as an open standard for use in geographical browsers, and is currently used by a number of websites and applications including Google Earth, Google Maps, Microsoft Virtual Earth, EarthSpector GIS and Geomedia amongst others.
KML files are used by several applications, though are often associated with Google Earth or Keyhole PRO, both of which are available on both Windows and Mac platforms. 3D modelling software such as Blender, an open source suite of 3D creation tools, and Google Sketchup are also capable of exporting models in KML format with the appropriate plug-ins for use with 3D geobrowsers such as Google Earth.