Reusability is the most important non-functional requirement and it is achieved trough Ginis
application framework. A design of the framework relies on use of explicit semantic descriptions for
building concrete systems (Stoimenov and Djordjević-Kajan, 2005). A semantic description of an
application domain consists of specification of a layer structure trough which geoinformation is
organized and services for geodata accessing and manipulation. For encoding of these descriptions we
defined XML language named Ginis Application Definition Language (GADL). The framework, on
the other hand, produces configurable application components that use GADL encoded semantics and
realize concrete applications and services of an overall WebGIS. A relationship between Ginis
framework and GADL is tight because both of them rely on a same model of a geoinformation system
that will be described in next section.