Geographic information becomes common object of digital data exchange. Several terabytes of data are sent between integrated software systems. They include a diversity of geographic information like datasets, geographic objects, cartographic representation as well as the geographic services declaration. However, every data exchange requires common agreement between all parts of the process as well as standardized rules and the format of data encoding. The Technical Committee ISO/TC 211 Geographic information/Geomatics of International Committee for Standardization faced those needs and launched a new work item on the standard for platform and independent software encoding of geographic information (ISO 19118 Geographic information - Encoding). In the meantime OpenGIS Consortium developed GML (Geography Markup Language). GML is the language for modelling, transfer storage of geographic information. In general, it provides the terms to formal description of real world phenomena and their spatial properties e.g. geographic objects, geometric and topological elements, spatial and temporal coordinate reference systems, as well as other aspects of geographic data like positional accuracy or measure units. In 2002 the OGC submitted the GML 2.0 as a new work item proposal to ISO/TC 211 in the field of geographic information encoding. It has been critisized by TC members mainly for the lack of topology and threedimensional geometry, but the general concept of standardized GML has been approved by TC 211. The current version 3.0 of the language seems to resolve great majority of problems found in the previous one, and ISO/TC 211 proposed it as the standardized GML (ISO/CD 19136: Geographic information - Geography Markup Language). What is more, the Technical Committee CEN/TC 287 of European Committee for Standardization (Poland is a full member of TC 287) proposed to participate in the work on international language for data transfer and storage. This cooperation of ISO and CEN is to result in 2005 in an international standard of geographic information encoding. This paper presents the general concept of GML 3.0 and the results of its analysis against the requirements it should satisfy as the international standard of data encoding. Because of the publisher is restrictions concerning the length of the paper the notation details, the content of predefined GML schemas as well as the rules of application schema definition were not included in this paper. Instead, the GML document example is given that, hopefully, brings closer the rules of GML data encoding and invites the reader to individual studies on GML language.