This part of ISO 19144 establishes the structure of a geographic information classification system, together with the mechanism for defining and registering the classifiers for such a system. It specifies the use of discrete coverages to represent the result of applying the classification system to a particular area and defines the technical structure of a register of classifiers in accordance with ISO 19135. The structure can be used to develop specific classification systems that address particular application areas, specified in other parts of ISO 19144.