Abstract: Recently, there arc some problems in integrating application model into GIS system, such as redundancy, difficulty to reuse the model and so on. We proposed a method to solve these problems. At first, the GIS application model was decomposed into sulrmodels, and the sulrmodcls and GIS functions were defined as services which arc provided to users. Then it defined the QoS (quality of service) of the GIS services. At last, the paper proposed a service composition method based on modified adaptive genetic algorithm (MAGA). The method can achieve the goal of global optimization of GIS services composition.

Key words: GIS services, QoS(Quality of Service) , Modified adaptive genetic algorithm(MAGA)