With a little help from a well described article from ArcGIS, let's learn the differences and similarities between KML files and KMZ files and what you can do with them on Google Earth and ArcGIS Online.

What is KML?

Keyhole Markup Language (KML) is an XML-based language provided by Google™ for defining the graphic display of spatial data in applications such as Google Earth™ and Google Maps™. KML enables these applications to support the open integration of custom data layers from many GIS users.

Each KML file is composed of a collection of graphic elements, images, and settings. KML is used to:

• Symbolize and display GIS data as elements within Google Earth™ and Google Maps™ using symbols, color, images, and balloon-style information popups.
• Provide access to attribute information about geographic features -- for example, by presenting attribute information when you click on a feature's placemark.
• Define the user's interaction with those features -- for example, to control fly-to and camera location settings in Google Earth™.

KML files have either a .kml file extension or a .kmz file extension (for compressed and zipped KML files).

In addition, map services published using ArcGIS Server can be served using KML. The KML content is retrieved each time the map service is accessed from ArcGIS Server. This enables KML content to be served dynamically using ArcGIS Server.


Google Earth(TM) and Google Maps(TM) support in ArcGIS
Many ArcGIS users want to leverage Google Earth™ and Google Maps™ in their daily work. These web applications provide digital basemaps onto which you can layer your operational GIS information and tasks. Many users want to publish their GIS contents and services to a larger set of users through Google Earth™ and Google Maps™ clients; for example, to provide citizen access to government information services published from their GIS.

KML can be used to display and work with georeferenced HTML. This enables GIS users to publish rich content about their geographic features through the formatted web pages and hyperlink capabilities provided by HTML.

KML can be accessed in ArcMap via the Data Interoperability extension. KML can also be accessed in ArcGlobe via its KML toolbar.

KML data can also be served dynamically on the Web using KML network links. ArcGIS Server can provide dynamic KML content through this mechanism.

Learn more about Using ArcGIS Server to dynamically serve KML

Continue reading the following topics to learn more about Authoring KML using ArcGIS Desktop

Common KML tasks in ArcGIS
Below is a list of some common KML tasks in ArcGIS and links to topics in this help system that you can click for more information.

Common KML tasks in ArcGIS