ABSTRACT
The objective addressed in this thesis is a discussion of methods to define and implement such contracts or protocols between interoperating parties, trying to find a better compromise between the two poles and going beyond traditional approaches based on, for example, file format standardization. The analysis of the interoperability requirements and impediments has identified semantical heterogeneities as a core problem in the context of geoprocessing. These heterogeneities need to be overcome when sharing and exchanging data and services2, that is, the contract defined needs to address these heterogeneities and provide means to cope with or overcome them. The approach proposed here is called Virtual Data Set and addresses heterogeneities by adopting an object-oriented model. An object-oriented model allows a compromise which increases both the degree of specification and the flexibility:
• Object-oriented models are much more expressive than, for instance, static data descriptions as it is possible to define methods to model the object’s behavior.
