Geovisualization based upon KML

The extension kml refers to a human readable file format that is based on a markup language deriving from XML and became rather popular mainly due to Google Earth. This type of files uses not only the classical geometric data, but coordinates of longitude and latitude (in case of 3D system also coordinate of altitude) to visualize the different geographically referenced objects, phenomena and processes. Nowadays more than 10 millions of kml files can be accessed via the internet, and this number is still increasing. However, knowledge of the standard features of kml is not always sufficient, because the circumstances of its application influence its usage. The functionality of the APIs for the web-embeddable Google Maps and Google Earth programs is determinative concerning this issue. The elements of the standard KML cannot be always used without any change, but the clever usage of the API can result effective tools of dynamism. My aim is to review how wide the range of kml files application is, to describe their differences and to share some personal experiences.