Keyhole Markup Language (KML) is a file format used to display geographic data in an earth browser, such as Google Earth, Google Maps, and Google Maps for mobile. It is an Open Geospatial Consortium (OGC) standard and is supported by major geospatial programs and applications. It contains the combination of points, lines, images and polygons to represent the world as seen on a map.

KML files are easy to create and can be accessed via URLs, making them popular for sharing geographic data online. More complex applications include features such as navigation, time-lapse sequences and 3D visualizations.

What is KML?

KML is a type of data file format used to express geographic annotation and visualization within two-dimensional maps and three-dimensional Earth browsers. Developed initially for use in Google Earth, KML uses a tag-based structure with nested elements and attributes, and is based on the XML standard.

KML enables users to develop, share, and consume spatial information with the capacity to annotate and overlay visualizations on top of map or Earth imagery. This allows for a large variety of visual representation in terms of point markers, 3D models, polygons, lines, and image overlays. KML also supports temporal or time-dependent information making it possible to include time control in geospatial data.


What is the difference between KML and KMZ?

The main difference lies in their level of compression. KML is an uncompressed file format while KMZ (Keyhole Markup Language Zipped) is the compressed version of a KML file. A KMZ file can be larger in size and can include additional resources like images that are utilized by the KML file.

How do you create a KML file?

KML files are typically created within a GIS software. They can be created manually by coding in a text editor or automatically through geoprocessing tools within software such as ArcGIS or QGIS. Google Earth also provides an intuitive interface for creating KML files with geographic data.

Which software supports KML files?

Many GIS software packages support KML files due to its open standard specification. Some examples include ArcGIS, QGIS, Google Earth, and Google Maps. Even various non-GIS software like Adobe Photoshop and Illustrator offer limited support for KML.

What type of data can be stored in KML files?

KML files can store a variety of geographic data types including points, lines, polygons, images, 3D models, and complex overlays. Additionally, the files can store attributes for each element and support the inclusion of timestamps or time spans for temporal data visualizations.

Ready to level up your map-making process?