Keyhole Markup Language (KML) is an XML-based markup language for annotating maps and other two- and three-dimensional geographic representations.
Keyhole Markup Language was developed by Keyhole Inc. for Google Maps and has also been used in other geowebs. The KML markup language became an open standard of the Open Geospatial Consortium in 2008.
Keyhole Markup Language works with vector elements: points, lines, circles and polygons. The representations can be displayed in two and three dimensions and can be changed in the viewing angle. KML files contain the functions for multidimensional representation in Google Maps and other online map services. The range of functions includes text notes, images, photos as well as the possibility to provide the positions with global coordinates. The grammar for the geographic documents is based on the Geographic Markup Language( GML).