This part of ISO 19144 specifies a Land Cover Meta Language (LCML) expressed as a UML metamodel that allows different land coverclassification systems to be described based on the physiognomic aspects. This part of ISO 19144 also specifies the detailed structure of a register for the extension of LCML but does not specify the maintenance of the register. This part of ISO 19144 recognizes that there exist a number of land coverclassification systems. It provides a common reference structure for the comparison and integration of data for any generic land coverclassification system, but does not intend to replace those classification systems.