Investigating metrics of geospatial web services: The case of a CEOS federated catalog service for earth observation data

Geospatial Web Services (GWS) make geospatial information and computing resources discoverable and accessible over the Web. Among them, Open Geospatial Consortium (OGC) standards-compliant data, catalog and processing services are most popular, and have been widely adopted and leveraged in geospatial research and applications. The GWS metrics, such as visit count, average processing time, and user distribution, are important to evaluate their overall performance and impacts. However, these metrics, especially of federated catalog service, have not been systematically evaluated and reported to relevant stakeholders from the point of view of service providers. Taking an integrated catalog service for earth observation data as an example, this paper describes metrics information retrieval, organization, and representation of a catalog service federation. An extensible and efficient log file analyzer is implemented to retrieve a variety of service metrics from the log file and store analysis results in an easily programmable format. An Ajax powered Web portal is built to provide stakeholders, sponsors, developers, partners, and other types of users with specific and relevant insights into metrics information in an interactive and informative form. The deployed system has provided useful information for periodical reports, service delivery, and decision support. The proposed measurement strategy and analytics framework can be a guidance to help GWS providers evaluate their services.