The research on QoS assessment and optimization for geospatial service chain

User experience and satisfaction of Web services and service chain are majorly determined by the quality of services (QoS), which is critical to services selection. Geo-data services and processing services are two fundamental services types of geo-services, where geo-data services provide geo-data, and processing services process and produce data. Therefore, the data quality of geo-data provided by geo-data services and the capabilities of geo-data processing to processing services are inherent characteristics and key quality factors of those geoservices. In this paper, the output quality factors are introduced to cope with above-mentioned characteristics of geo-services. Coupling with process quality factors (common measurement quality factors of Web services), a preliminary QoS assessment model for geo-services is proposed. The dynamic feature and the aggregation functions of QoS factors are discussed. Finally, a services instances´ optimization selection algorithm based on linear programming is designed.