| Keyhole Markup Language | |
| Extension: | .kml, .kmz |
| Mime: | application/vnd.google-earth.kml+xml, application/vnd.google-earth.kmz |
| Owner: | |
| Genre: | Geographic Information System |
| Extended From: | XML |
The KML file specifies a set of features (placemarks, images, polygons, 3D models, textual descriptions, etc.) for display in Google Earth, Maps and Mobile, or any other 3D earth browser (geobrowser) implementing the KML encoding. Each place always has a longitude and a latitude. Other data can make the view more specific, such as tilt, heading, altitude, which together define a "camera view". KML shares some of the same structural grammar as GMLhttp://geoweb.blog.com/313918/. Some KML information cannot be viewed in Google Maps or Mobile http://maps.google.com/support/bin/answer.py?answer=41136&topic=1475.
KML files are very often distributed as KMZ files, which are zipped KML files with a .kmz extension. When a KMZ file is unzipped, a single "doc.kml" is found along with any overlay and icon images referenced in the KML.
Example KML document:
<?xml version="1.0" encoding="UTF-8"?> <kml xmlns="http://earth.google.com/kml/2.0"> <Placemark> <description>New York City</description> <name>New York City</name> <Point> <coordinates>-74.006393,40.714172,0</coordinates> </Point> </Placemark> </kml>
The MIME type associated to KML is application/vnd.google-earth.kml+xml.
The MIME type associated to KMZ is application/vnd.google-earth.kmz .
For its reference system, KML uses geographic coordinates (latitude and longitude) in the World Geodetic System of 1984 (WGS84). However it does not support the general idea of the geodetic reference system, in which there are multiple coordinate systems of the Earth for which geographic coordinates could be defined. It therefore can not be used for professional purposes in Geomatics or Geodesy.
The KML 2.2 specification has been submitted to the Open Geospatial Consortium to assure its status as an open standard for all geobrowsers. As of November 2007, the OGC has a new KML 2.2 Standards Working Group. Comments were sought on the proposed standard until January 4 2008.[1]