The importance of geotagging has significantly increased in the last years. Nowadays it is necessary to be able to georeference not only maps, airborne images or remotely sensed data, but also private pictures, news related to locations etc.

The growing demand for such locational information resulted in different data formats and encoding standards which allow transfer, distribution and (for some of them) also representation of geographic features and geo-related events on the web.

This paper describes and evaluates the main geotagging formats available today.

These are XML-based standards, like: GeoRSS, GML, KML and others like: GeoJSON and WKT.

They are evaluated with respect to their complexity, availability of predefined geometries, extensibility and integration of spatial reference systems and the definition of the latter.

In addition, an overview of major applications using those formats and providing interfaces or parsers is provided.