Interoperability requires full exchange of data between the systems' heterogeneous data models. For an exchange to take place, a consistent set of interpretations must be provided for the information. Thus, interoperability relies heavily upon communication of information between organizations, application programs, and databases wherein formal language and model representations of complex geographic information have been resolved. Efforts to create standards for the interchange of geographic information over the past 10 to 15 years have produced a number of national and international standards documents. Much effort has been directed at formalizing general aspects of storing and retrieving geographic properties and entities, notably cartographic entities.
Metadata comprise a key component for any interoperability scheme.
Metadata have received attention but are generally viewed as headers on the data. As the format of metadata evolves towards a machine readable form, improved reliability and consistency in the interchange of geographic information will occur. Further work is needed in storing and representing metadata, specifying metadata requirements for geographic domains, and building tools that are able to find commonalties between interchanged data from different agencies. Such interpretation necessitates a considerable amount of research into the development of approaches for formally representing geographic phenomena in terms of their structure, semantics, and behavior. The issues and theories that emerge from research on interoperability may well serve the long-term goal of improving semantic representation and developing language standards for communicating geographic information.