File extension

.kml

KML (Keyhole Markup Language)

.kml files are Keyhole Markup Language documents: an XML format for describing geographic placemarks, paths, polygons, overlays, and styling for display in earth browsers and mapping software.

Known meanings

Formats and reference material for .kml

KML (Keyhole Markup Language)

XML-based geographic annotation and visualization format, an OGC standard

  • gis-formats data-format
  • Google / Open Geospatial Consortium
Open link

KML reference

Google reference documentation for KML elements

  • gis-formats
  • Google
Open link

Details

Format notes

KML (Keyhole Markup Language)

KML is an XML-based language for expressing geographic data and how it should be presented. It was developed for Keyhole’s EarthViewer, which became Google Earth, and was adopted as an Open Geospatial Consortium (OGC) standard in 2008. A KML file describes features such as placemarks, lines, polygons, and 3D models, along with styles, descriptions, ground and screen overlays, camera views, and time information.

Technical Notes

A KML file is UTF-8 XML whose root element is <kml> in the OGC KML namespace, typically containing a Document or Folder of Placemark elements. Coordinates are written as longitude, latitude, and optional altitude. Features can reference remote resources through NetworkLink, which lets a file load or refresh content from a server. When a KML file needs to travel together with images or models it references, it is packaged as a .kmz archive.

Adoption

KML is supported by Google Earth, Google Maps and My Maps, and many GIS programs, GPS tools, and web mapping libraries. It is focused on visualization, so for analysis and exchange of attribute-rich data, formats such as GeoJSON, GeoPackage, or Shapefile are often preferred.

Preservation And Security Notes

Because KML is open, textual XML, it is easy to inspect and convert. Linked overlays, icons, and network links may not be reachable in the future, so embed or archive referenced resources (for example, by using KMZ). Treat files from untrusted sources carefully: network links can trigger outbound requests, and XML parsers should disable external entity processing.

Further Reading

  • OGC KML standard: https://www.ogc.org/standards/kml/
  • KML Reference (Google): https://developers.google.com/kml/documentation/kmlreference